Keithley 165 Instruction Manual

INSTRUCTION MANUAL MODEL I65 DIGITAL MULTIMETER 0 COPYRIGHT 1975 KEITHLEY INSTRUMENTS, INC. PRINTED JANUARY, 1977, CLEVELAND, OHIO U. S. A.

. . Specifications . . . . . 1. General DeSCriprion 1-l. Introduction . . l-2. warranty Information 1-3. Change sotice. . . 1-4. Features . . . 3. circuit Descripeion 3-1. General. . . . . . . 3-2. *c-"o1cs Preamplifier. . 3-3. DC-vo1rs PraamplFfLer. . 3-4. OhrnP circuitry . . . . . 3-5. 1-d currene source. . 3-b. DC-r\mps Preamplifier . 3-7. *c-Amps Preamplifier . . 3-8. hipolar Amplifier . . 3-9. AD ConverCer . . . . 3-m. Clock. . . . . . . . 3-11. Logic. . . . . . . . . 3-12. Display. . . . . . . . . 1-13. Power supply . . . . . . 4 5 5 5 5 6 7 . 8 . 9 9 10 . 10 . 10 . 11 11 . 11 . 11 . 11 . 12 . 13 . 13 . 13 . 13 4. Accessories 4-1. General. . 4-2. operating Instructions . 4-3. Model 1651 50-Ampere S~UOL 4-4. Model 1653 Rack Mounting K~L 5. Maintenance 5-1. General. . . . 5-2. Recommended Tesr Equipment 5-3. Performance YerificaLia" . 5-4. Calibration. . 5-5. companenr an* Calibration Layouts . . . 5-b. some Semiconductor case ouc1ines and Pin Identificarions . 5-7. Tra"bleshoati.ng. . 6. Replaceable P,,CS b-l. General. . . . . b-2. Electrical Schematics and Diagrams. . . . . . . b-3. How to "se the Parts list. . b-4. How LO Order Parts . . 6-5. Chassis Pares List . b-6. Electrical Parts List. . . 6-7. Mechanical Parts IAt. b-8. Code-to-Name List, . . . 7. scbmatic Diagrams 7-l. 253950 Block DFagram. . . . . 7-2. 2539ZE AC & DC Preampltiier SwiCchtig . . . . . . 7-3. 253930 "*ipolar Amplifier 61 A-D canverrer . . . 7-4. 255080 Clack & Switching Logic. 7-5. 25511D Re y b Drivers. . . 7-6. 25394E Readout and logic. 7-7. 25391c Power supply . . . 15 15 15 15 16 16 16 20 27 29 31 34 34 34 34 35 35 49 50 52 53 54 55 56 57 58

CAL CONTROLS ANALOG CAL POWER LINE LINE FLiSE OUTPUTS CONTROL INPUT SWITCH SWITCH F301 P304 5303 s302

a= ,unctions of Ed0 dissimilar metals are thermoelectric noises, more commn1y called thermal mm. These potencia1s may be significant when making millivolt or mic=o- volt mea*uremencs. TO minimize ehermal nOiS* --- which may appear as a drift --- caused by thermal FXYO, use PUT* capper circuirry emi tswinaricms thrau*iw*t the source an* in a11 connectians to ehe 165. The KeicNey accessory Model 1483 Low Thermal Connection Kit contains all necessa=y ma- cerias for making very law-thermal copper connec- tions for minimir*n* tharmal mm.. 2. AC Power Line Noise. The presence of electric fields generated by power lines o= other power .9O"TceB can haYe an effect 0" inaaur,ent operarim. Also ac vok?.ges presenr in Ehe BOUrCe which are very large vith reapact. to the full-scale range sensitivity of the Model 165 could drive the analog amplifier into sa~uracio". producing an e==OneO"a digiral display. a). Shielding. Proper shielding of the sowxe or cabling can minimize noise pickup when the instrument is in tile presence of large ac fields or when very seneirive me*e"rements are being rude. ‘ornoiae shielded cable, such as Keith+, SC-9 cable, should do a sufficient job of shield- ing rhe inpur signal. Metal shields may be re- quired LO be installed arD""d the BOUIICB. me shields of the inpur cable and source should be connected together co ground at ooe point only, typically at the input of the Model 165. This one-point-ground method ia a frtree'f configuracio", which minimi=es ground L,ape in the measured cir- cuiery. Ground loops are a secondary source of interfering noise Which may also be considered in larle"el meee"reme"ts. OPERATION b). AC Ke,ecrim. The Model 165 provides artenuation of line frequency noise superimpose* on a dc input signal. The ac re,ection Of the 165 is specified as follows: NOWL MODE kE.lECTION RATIO (NMI(Io: Greater than 60 dB above one digit for a voltage of line frequency o= twice line frequency with at leas= 10% of full-range dc applied. COMmN MODE REJECTION RATlO (cxea): 120 dB on the 10 mv, 100 mv. and 1" ranges; 80 da 0" the 10" range; 70 da on the 100" range; and 60 dB an the 1000" range; far a dc, 50 HZ, o= 60 Hz voltage with at least 10% of full-range dc applkd. 3. Magnetic-fFeld Noise. The presence of strong magnetic fields can be a possible so"=ce of obJec- eionable ac noise. The Model 165 has been suffi- ciently sbialded from typical magnetic incerfarence; however, additional shielding may be required at the eo"rce or in the cabling to the 165. Magnetic flux lines which cue a conductor --- like an input cable --- can produce large ac noise, especially at power line frequencies. me voltage induced due to nag- neric flux is proportional to the area enclosed by the Circuit *s well as the rate of change of mag- netic flux. POC example, the motion of a ,-inch *iemeeer loop in the earth'. magnetic field will induce a signal of several tenths of a microvolt. The ac rejecrion characteristics of ebe Model 165 vi.11 help minimize specific effects of magnetio fields. Magnetic pickup may be furthe= minimized, by arranging all so"=ce and input-cable wiring so L&E the loop area enclosed 18 BB small as possible (such as by rwisring input leads). "sing conetic (magnetic) shielding in cables and around cirwia-j may further help in seve=e cases. b. Effective Shielding. Here are general shielding rules fo consider far measurements in the three func- tion categories of the 165. Be sure that shielding is even needed before proceeding. 1. Yolemeeer maaurements. Consider shielding input leads when sou=ce resistances a=e g=eaCe= than 100 kilc,hm o= when long input cables are used. Avoid even slight movements of input cabling a= Ct\e oource when making high s.au=ce resistance measurements. 2. C"rrenC Mea8"reme"C*, on the mA and ii.4 current ranges, generally no ape&a1 shielding precautions need ba taken. However, consider shielded input leads for me~~"=ements an the lowese ranges. 3. Reeiscance *easuremenc*. Shielding Of the input cabling and sou=‘ce may be necessary far meas- "remente on the 10 megohm and 100 megohm ranges. 4 1073 .~. P .

the factory applications deparcmenr or your local Keithley rrpresenrarive for instructions. d. Turn ox power Switch 5301. 2-3. CONNECTIONS. (refer ta Figures 2 and 3). a. Innut. Three binding posts are provided an the frO"C piln.21 LOT input connections. The cermina1s are color-coded a* follows: red = input high (HI) 5401, black = input low (LO) ,402, and green = power- line ground (Clm) ,403. These terminals mace Wifh individual "ban*"*" plugs similar LO Keichley Parr NO. c-5, The from pane1 terminals are spaced with ,/Ii-inch bewee" centers to mate wit,, a standard dual "banana" plug such as Keitbley Part No. Lx-,. Banana-plug-co-alligator-clip cables (available through my local electronics supply house), such as two Keithley Part No. 181620 cables, are ideal for fast connections to the 165 input. The shorting link provided at the input should be connected between LO and cm for grounded operacian. IC is preferable, to minimize rhe pas5ible effects of ground loops (small mrrents flowing in the ground system), that there be only one ground point in the measuring syseem. If possible, connect all grounds together at one poinr, ideally ac the CND input terminal of the 165. 'Tire input ShorrFng link should be removed for floaLi"g OpcrdLiO".

The Model 165 provide5 five and one-half decades (six ranees, of ac vo1caee T .

ac voltage ranges is I megohm 110% shunted by less rhan 75 picafarads of capacirance. 3. Accuracy. The Model 165 detects the average value Of a" applied input ac waveform. The display of the 165 is calibcnted LO indicate the n,,s value of an applied sinewave. The accuracy (error Limit) calculations given in Paragraph Z-ha, ah.0 apply far ac measurements, except cilai 20 HE and ZOlcHZ, the specified accuracy is asymmetica1. Reference the specified ac-volts accuracy ranges a~ 20 Hz, lkkiz, an* 20w*. Typical aCCUraCy bands at non- specified frequencies ace shown in Figure 6. 5. rlaximum Allowable Input. Ihe maximum contin- uous or i"termifLe"t input voltage which calI be safely applied 0" manually selected l-volt and lower ranges is 250 "0lt.S rms. when aperacing manually on the 10 volt to 500 volt mls ranges or in the auroranging mode on a11 ranges, the maximum con- cinuous or inrermiCce*t inpur voltage which can be safely applied is 1200 volts peak ac + dc. on the 5O&volc rms range (1000 volt range pasitio") in either ranging mode, the 165 display will flash when the inpui exceeds 499 volts rms, although a reading beyond this level is displayed. 2-7. OPERATION AS AN AXXETER. The Xodel 165 can be used to measure C"rre"L from 21 nanoamp to t2 amps dc and 100 nanoamps to 2 amps C"S ac. 3. Accuracy. The dc-current accuracy Of the 165 is t(o.3% of reading + 0.3% Of range). The error limit of a given measurement can b< Cal- culated using this specifiearia" (see Paragraph Z-6=3) and the voltage burden (see Paragraph Z;i,l,

which cause excessive heating or vaporization of pc-board tapes. 1. Measuremenr Procedure. Selecr ehe AC AMPS function using the FUNCTION switch, set the RANGE switch. and make input connections to the front- pane1 cermina1s. The digital display indicates the decimal point locaeion and engineering units Of a reading. The polarity Lag” “ill not light when AC amps is eeleceed. If the display exceeds 1999 on the 100 milliamp or lower raoges, the three right-hand digits will blank and ehe overrange "1" digit will remain lit. See Paragraph 2-?a5 far details af the maximum allowable Fnpur. 2. Input Resistance. See Paragraph 2-7a2. 3. Accuracy. The aC-C"rre"f accuracy apecifi- cation of the 165 is used co calculate the error limit of a Specific mea*ureme"t (see Paragraph 2-6a3). except at 20 Hz and 2OkHz where specified accuracy is asymmtri~al. Reference the specified ac-amps accuracy ranges a~ 20 "z, lkI+z, and 2O&. Typical accuracy bands af non-specified frequencies are shown in Figure 6, alrhough rhe 10-1000 mA ran8e has somewhar flatter responsa at 2Ok"z than char shawn. Voltage burden (see Paragraph 2-7b2) can also produce error, depending on the level of rhe source "alcage. 4. Half-dIgit I"terpo1ari.o". see Paragraph 2-74. 5. Marimum Allowable Input. See Paragraph 2-7a5. 2-8. OPERATION AS AN OHMMETER. The Model 165 can be used CO measure resistance from 0.1 ohm co 200 meg- ohms. The Model 165 ~ravides se"en full-range decades of resisrance fram 100 ahms LO 100 megohms. Range seleccio" can be accomplished either manually x autamarically. w selection is accomplished by setting the RANGE switch S401B LO any ""e of seven positions, g including the secand position from full clockwise. i"his wsicion may be used but it just duplicates the operarion of the 100 megohm runs, which is the third position from full clock- * NODEt 165 wise. As the RANGE switch is rotated counterclock- wise. the 165 resistance sensitivity is increased. Automatic selection of range is accomplished by rotating the RANGE switch to rhe extreme clockwise position marked AUTO. a. Measurement Procedure. Select the OHMS func- tion "siw, the FUNCTION switch. set the RANGE switch. and make input c""necrio"s t" ;he front-pa"el ter- minals. The digital d$splay indicates decimal 1 location and engineering units of a reading. ': POlEdry sign "ill not light when ohms is selec:~ If the display exceeds 1999 "n any range, the three right-band digits will blank and the overrange "1" *igir Will remain Iit. 1" the AUTO mode or manually on the oueside IOO-megobm position, a" open-circuit input ca"~es a flashing 01.7 W display. With an open in~ue, the inside IN,-megohm range, the third p"si~ion from full clockwise, may flash or blank de- pending a" whether it was entered from the outside lOO-megobm renge or the lo-megohm range. Also, if the RANGE switch is rotated rapidly while in the AUTO made, the display may blank. Neither candician just discussed represents a problem or malfunction. aa shown in Table 2-4. The HI input t&inal 5401 is. negative with respect to the LO input terminal 3402. The rermina1 voltage is 100 mulLvolts at full ranz>. (200 millivolta at maximum overrange reading). maximum open-circuit voltage is less than 1 volt. TABLE 2-4. Ohm Test C”rrenr Full Pull-Range Teat Range Terminal VAtaga Current 100 n 100 In" 1 k0 100 02" 1~0 k" I"0 rn" lm.4 ,. 100 "A 10 p.4 100 kn 100 I"" 1 UA 1 I% 100 r&Y 100 "A 10 MO 100 mv 10 "A 100 ML-z 100 mv 1”A C. *muracY. The accuracy far all abms ranges is as specified. This apecificario" applies far envi- ronmental conditions of 35'C at up to 10% relative humidify. Accuracy on the l-megohm and higher ranges is typically two-times better than specifications. The error limit of a given mea*urement can be cal- culatcd using the specified accuracies as described in Paragraph 2-6~~3. d. Half-digit Interwlation. When the m"st right- hand digit of the 165 display is flashing berwee" two adjacen; numbers, the percentage of time spent on each is a half-digit intarpalario" of zhe incoming signal level. POT example, 1.000 kilOhmS flashing in near- equal intervals LO 1.001 kilobms would indicate a reading of 1.0005 kilobma. e. Maximum Allowable Input. The maximum Yolrage which can be applied to the input Fn the OHMS func- tion ia 250 va1ts rms on any range. This voltage may be applied continuously or ineermictenely with- out damage or degradation af ~pecificati""s. 1073 7,.

pushbutton aCti”*fes * cLIrre*t source of +1 mA *10x. The current 18 internally injected into the HI input terminal 5401. voltage compliance is cypica11y *rearer than 4 vo1r.s. a. Reeiarance Measurements. If the DC VOLTS func- tion is selected while usinp. the 1 mA current BOUXCB, the Model 165 becomes a dir&-reading autora”ginS z manual ranging ohmmeter having 100% overran&g on ranges from 10.00 ohs co 1.000 kilohms full-scale (corresponding respectively co 10.00 millivolr through 1.000 volt dc ***ges). Useful measurements are available to 4.00 kilohms (corresponding LO 4.00 volts on the 10.00 volt dc range). I” any c**e. the Yoltage compliance limif is also the 1iraiL of resistance measurements using the 1mA C”rre”t source. Note that rhe engineerI.“* uni~a on the display will scFll indicate volts, which is the voltage compliance at which maaauremenrs are being made. Af the 8-a time, the displayed numbers in the reading indicate the value of the resistance being measured. For example, * reading of 100.0 milli- volts dc indicates the meaeured resistance is 100.0 ohms and a reading of 1.999 volts dc indicates 1.999 kildlm. 1. Measuremanr Procedure. The ImA current source feature of rhe Model 165 may be used to measure low resistances or to check continuity. A” open cir- C”it or resisrsnce grearer aaLl the range limit is indicated by a display of the full compliance volt- age. This voltage ia eaefly determined by open- cFccuiting in the input terminals of the 165 and depressing the lmA pushburro” “bile operating in the DC YOLTS~funcfio” eithsr manvally on the IO- volt range or in the AUTO range mode. 2. Compensaring for Lead Resistance. A precise value of the ImA current source (I) can be obtained by open-circuiting the input terminals, eelecting the DC AMPS function, and depressing rbe ImA push- button; The resistance of the test leads and in- ternal connections (P& CB” be directly measured by shorting the teat leads’while in the DC VOLTS function and depressing the 1mA pushbucto”. The” the measured resistance (R) cm be more arrnrately defermined as follows: where ” is the observed voltage during the actual measurement of R. b. Semiconductor Testi”~. In the DC YOLTS function and AUTO range mode, the ImA current source may be used to determine polarity of a semiconductor junc- tion. The forward voltage drop of this juncria” at lti is displayed a” the Model 165 if Lhe junction is connecred between the input terminals in the foward polarity. Note thaf the lmA c”rre”f *.a”rce is inter- nally injected into the HI input terminal 5401. I” the m palartty position, Lhe display will ,.“- dicafe the compliance voltage limit of the current source> which can be measured as described in Para- graph Z-gal. 1073 OPERATION DO NOT DEFRESS THE 1mA POS”B”TTON WHEN MTWJAL VOLTAGE IS APPLIED TO THE INPUT TERMINALS. Z-10. OPERATIONS SUMMARY. Condensed operating in- structions are found on rhe botton cover of the Model 165. They are repeated here with a little more detail. For complete details of operation. see 2-l Lbrou$h 2-9. e. Power. Set Lhe rear-psoel line witches 5302 and S303 to the proper line voltage ~etti”Ss. Check the fuse F301 for proper rating. Connecr the line cord CD-7 to 50 or 60 Hz power. Set the power switch S301 to ON. b. Co*“aCfio”.9. connacr to the fro”=-pane1 “I tied) 5401 and LO (black) J402 binding poet Fnput Cemlinals . Connect the ground link between CND (sreen) 5403 and LO (black) for grounded operation. discon”ecting rbe link for floating operation. Haximum allowed voltage becvaen CND and “I or LO is l200” peak. C. Function Selection. Set the outer dial to the desired function: DC VOLTS, AC VOLTS, DC ANPS, AC Ams, or OHMS. The digital LED display automatically indicates decimal point, polarity, and-e”$ineering U”5LS. Lack of polericy on the display on YOLTS or AMPS functions Fndicatas ac readLngs. d. Range Selection. 2. Automatic. Set the inner dial to the fully- clockwise position (AUTO). In this position. the 165 automatically “prangea at 2000 digits and _ dawnranges at 179 digirs. e. lmA current source. If the front-panel In.4 wabbutto” is depressed. arwroximatelv +ImA is in- jected into the i,I input t&minal at ;p to appror- imarely 4 volts compliance. Set the RANGE switch co DC VOLTS. For semiconductor tests. forward voltage at ImA is read direcrly. For continuity or resisLance measurements, resistance is read in ohms using millivolt dc ranges in kilohmn using volts dc ranges (limited to compliance voltage level). With an open-circuited input actual compliance and current can be meaaurad on DC VOLTS and DC AMPS respectively. NOTE DO NOT DEPRESS THE 1mA P"SHB"TTON WHEN MTERNAl VOLTAGE IS APPLLm TO THE INPUT TERMINALS. f. Zero. The DC ZERO potentiometer R431 on the rear panel may be adjusted for a +O display with the Fnput shorted on the 10 millivolt dc range or with B” open input on cbe 1 microamp dc range. 9 T \

diagram of the Model 165 is shown in Scbemaric 25395D. The eiS"*l applied to the input rerminals first goes rhrough en input switchinS network and then ie applied to'* dc or ac preamplifier. A ""ipolar amplifier co""er‘c8 the signal to a positive dc signal which ie the" applied to *" a-d converter. The s-d control and display logic ie contained in the LSI cirx"iZ. snd on the display printed circuit boards. The numerical information corresponding to the input signal is displayed a" LED digits. The logic properly positions the decimal point and indicates engineering ""its. The inpur swircbitq network is cootrolled from the logic in the AUTO range mode or from the front panel manual range switch. 3-2. AC-VOLTS PWLIFIKR.. (see Schprmaric 2539%). The signal applied *c ebe Fnput tenninela is coupled through cepaci~or C401 CO a" *c-compensated ae~enuator consisting of RN403 and C402 through C405. TN* ie shunted by en input resietence consisting of R401 and R437, and switchi"* is accomollshed bv meene of PUNC- TION awitch S4Ol.A Deck No. 2: Table i-1 show* the attenuation end gain factors ee well *a relay aate* for each *c-volt* range. TABLE 3-1. AC Volts: Gains and Relay St*ce* RN403 AMP. ;F.ANGE ATTENUATION K401 K402 K403 GAIN Q406 9407 Q40R lO@lV I:1 ON OFF OFF xl00 OFF OFF ON 1Oh" 1:1 ON OFF OFF x 10 OFF ON OFF 1” 1:1 ON OFF OFF x 1 ON OFF OFF 10 V 100 : 1 OFF ON OFF x 10 OFF ON OFF 100 " 1000 : 1 OFF OFF ON x 10 OFF ow OFF 500 " 1000 : 1 OFF OFF ON x 1ON OFF OFF CIRCUIT DESCRIPTIdN MODEL SECTION 3. CIRCUIT DESCRIPTION a. On the 1 Volt Range. On the 1 volt range, K401 16 closed, K402 and K403 *re open, end the siSn*l is applied through resistors R405 end K406 to the input of s Xl amplifier QA403. The input to this amplifier is limited to the power supply level* by D419 end D420. Overload voltages applied *c the input are dissipated in R40S and R406. SwitchinS ie accomplished throuSh S4OLA Deck No. 6. On the 1 volt range Q406 is on, 9407 and Q4OS *re off. The output is coupled fo the unipolar amplifier through c422 end swirching ie accomplished through S401.4 Deck Nos. 7 and 8. b. On the 100 Millivolt R*n*e. On the 100 milli- "olL ran8e. the ouLp"t of QA403 is applied co a *LO amplifier Q.4404. Q407 as on, Q406 and 9408 are off. therefore the input siS"a1 ie amplified by * facror of 10 before being applied to the unipolar amplifier aSsin through C422. C. 0" the 10 Millivolt Range. 0" the 10 mini- volt ran@, a second x 10 amplifier 9.4405 further amplifies the signal and it 16 applied tbrouSh 4408 co the unipolar amplifier. d. 0" the 10 Volt Se"*e. On rhe 10 vole **"Se, K401 *"d K403.are off, K402 is on. Thus, RN403 attenuates the siSn*l by a factor of 100. The eigr ie then applied to the emplifier chain QA403 and QA404, "ith Q407 on, selectinS the xlO,S*i" for cb, chain. Thus, the signal ia attenuered by 100 and amplified by 10 for e "et atreauatio" of a factor of 10 bafore going to the unipolar smplifier. e. 0" the 100 Volt Range. 0" the 100 volt **age K403 is on, K402 and K401 *re off, end the input signal is attetuated by a factor of 1000 before being applied to the x10 amplifier chain. Q407 remains on and the *et *cte"u*cio" ie a factor of 100. f. 0" the 500 Volt P.ewSe. On the 500 Volt range: K403 remains on, and 9406 is on selectinn the xl gain for the amplifier chain. Thus, the-net ecte"- uafio" LB a factor of 1000. C402 and C403 *re ad- justed to *c-compensate the *ttenu*tor KN403. 3-3. DC-"OLTS PREAMPLLFISR. (see SCbemaLiC 25392E) The inpur signal is applied to the sttenuetor RN403 e8ein t,,rooSh ewiccb S4Ol.A Deck No. 2. The outp"t c the attenustor, e.8 selected by K401 through K403, ie applied tbroqh S4OlA Deck No. 4 and limiting resie- tars R420 and R421 to the input of * dc amplifier *L S401A Deck No. 5, “‘DC INPUT”. a. DC Amolifier. The dc amplifier consists of a FET modulator Q4OLA end QLIOlB, protected by D410 through 0413, e" ac empltiier QA403 through QA405 whose bW.n is controlled as in Paregraphs 3-2, e demodulator 9409, and a final dc ampIFfier coosis- ring of QA406. The output of this mep1if1er "DC PREAMP OUTPUT” is fed back to the input by resistanct elements in RN403, selected by K404 and K405. These relays select Paine of 1, 10, or 100. Table 3-2 shows the attenuario" gain fsctors ** well a* relay states for each dc-volts **"Se. TABLE 3-2 DC volts: Gains and Relay Stetee RN403 AMP. UNGE ATTENIIATION K401 K402 K403 GAIN K404 K40 1hnV 1:1 ON OFF OFF x100 OFF OFF 1oomv 1:1 ON OFP OFF Y 10 ON OFF 1" 1:l ON OFF OFF x 1 OFF ON 10 v 100 : 1 OFF ON OFF 1 10 ON OFP 100 ” 1000 : 1 OFF OFF ON xl0 ON OFF 1000 v 1000 : 1 OFF OFF ON x 1 OFF ON b. Modulator and Demodulator. The modulator and demodulator are operated at e frequency of 220 Kz. This is developed at the "t44" output of the LSI chip *"d appears in the middle of Schematic 25392E "ear the bottom. S4OU Deck No. 1 disable8 the sig- nal on ec functions. On dc functions, fwo phase8 10

They sre coupled to the modulator gates by c417 and C418, and to the demodulator by c409. 0421 an* 0422 clamp the gate *rives co a reference level equal to the feed- back "olrsge. developed by QA409, a Xl amplifier whose input is connected to the feedback point. c. Input Zeroing. Input seroing is accomplished by R431 which determines rhe current throunh R428 and R429. The voltage ,vzneraced by this c”rr&t across R428 is added to the feedback “olLaSe developed across the lo-kilohm element ,,f RN403 between pins 6 and 7. “se a pure copper wire end a dual banana plug for a shorting plug. CIRCUIT DESCRIPTION The reference resistance consists of F.409. and R414 rbrouSh R419. .The specific value of the resistance is determined by the state of relays K409 through K415. The rota1 resisfsnce is equal to the full- ran8e resistance. Note that this circuit applies a ne$sti”e reference currant through the unknown resi*Lance. 3-5. le. CURRENT SO”RCE. bee Schemetic 25392E). The lmA current is developed by 9404, R411 through R413 and D405. It is applied LO the HI renninal by mean8 of rile fronr pane1 BWitCh S402. R410 ad D406 protect 9404 if S402 is eccidantally depressed while the voltage is applied to the HI terminal. d. Input Offset Current. Input offset current is comwnsated for b” ad,usrinp. R424 “hich develow a “o&e referenceh to-the f;edback point at the o”t- put of QA409. This voltage generates a compensafing current through R423 which is applied to the common node of the FET modulators, Q4OU and Q4OlB. e. Offset “olra*es. Offset “oltaSes within the dc amplifier loop are compensated for by R434 which ap- plies a volrage to the positi”e input terminal of QA406, the final dc amplifier. The controlling time constant within the loop is determined by C413 and R427 in the negative feedback loop of Q.4406. 3-4. OHMS CIRC"ITRY. (sea Schematic 25392E). on a11 ahms ranges, K404 and 9407 are on, firing the dc “alt- age preamplifier at 100 millivolts full range. D416 near QA406 limits the output of this amplifier such that no more than 1 volt appears at the ioput under open-circuit conditions. The ohms circuit in the lower left corner of Schematic 25392E generates a reference current at the input terminals. This ref- erence c”rre”f is generated by a “oleage at “0 OUT” G4OU Deck No. 3) divided by a reference resistance selected by K409 through K415. 8. Reference Voltage. The reference voltage is the sunnnacion of 0.1 times the “DC PRW OUTPUT”, and a fixed lOO-millivolt reference. QA402 performs this summafion. R462 and R463 provide an output of 0.08 times “DC PW OUTPUT” BL their iunction. This voltage is applied to rhe positive-input terminal of QA402 which has a non-in”errinS gain of 1.25 de- termined by R407 and R461. 9405 is on in normal OperaLion. The lOO-milli”alt reference is developed from an aftenuaeor scros~ the g-volt reference diode D408 consisrin~ of R458. R402, and R465. The “olt- age at R465 is about -1.6 volts. This is amplified by -0.25 using QA401, and by another -0.25 with QA402. b. Overload Conditions. Under negati”e overloads, D418 blocks current flow to 9405 or QA402 output, and 0415 limits the input “oILage at the naSafi”e terminal of QA402 to the supply “olfaSe. Under positive o”er- loads, D414 limits the neSari”a input of QA402 to the positive voltage. This drives the output of QA402 negative until it is limited by D426. AC that level, the c”rrenf flow in the emitter of Q405 is determined by voltage across D426, rhe base-emitter drop in 4405, R454. and R408. These elements limit the collector current in 9405 LO abo”f 1.2 milliamps. This current is essentially independent of the voltage appaariwj at the collector of Q405, which ie determined by the po~itive voltage at the HI terminal and the voltage drop of the 1.2 milllamps in the reference resistance. 1073 3-6. DC-AMPS PREAMPLIFIER. (see Schematic 25392E). The Fnput c”rre”t passes rbro”Sh S4OlA Deck No. 2 to a reference resistance selected by K406 throush K411. The voltage across chin reference resistance is sensed by the dc amplifier in B 4-terminal method between terminal 1 of RN401 (at circuit LO) and junc- Cio” of K411 end R415, which is applied to the inpur of the amplifier through S401A Deck No. 4, R420, and R421. 0” the I-microamp through 1OO-milliamp ranges. the dc preamplifier is set to a gain of 100, COP respondinS co a full-range voltage of 10 millivolts. On these radges, K406 through K411 select the refer- ence resistance which covers s span from 0.1 ohm (in RN401) through 9 kilohms u(415). On rha IOOO- mflliamp range, K406 selects the 0.1 ohm resistance in RN401, and the gain of the dc preamplifier is changed to 10. correspondinS LO 100 millivolts full ran$a, as indicated in ParaSraphs 3-3. D401 rhrouSh D404 protects rhe relays and the sensing resistances from overcurrent. 3-7. AC-Am3 PRWLHPLIFIRR. (see Schematic 25392E). As in the case of dc amps. the BC input current is passed tbraugh S4OU Deck No. 2 to a sensing resis- tance selected by relays. In this cE.se, only re1#ys K406 thrc.“Sh K409 are used. The output voltage is , sensed at S4Ol.A Deck No. 3 and coupled through C401, S4OU Deck No. 2, and R455 to the AC Preamplifier, chain. The ac preamplifier is set to a gain of 100 corresponding to IO millivolts full range on the 100 microamp rhrouSh 100 milliamp ranges. a Sain of 10 corresponding to 100 milli”olLs full range on rhe 1000 rsilliamp ac amps range, selected as in Paragraphs 3-2. As in the case of dc amps, D401 throuSh D404 protect the relays and sensing resista”ce from a”erc”rreoL. Note that since the capacitor-couplin8 through C401 OCC”rs I.” the circuit folloving the sensing resis- tances, dc or ac ~“ercurrents .3 A may hsve danaSing affects on either DC AEIPS or AC AMPS functions. 3-8. “NIPOLAR AMPLIFIER. bee Schematic 25393D). This circuit, consistinS of QUO2 and QA203. is shown in the left-half of Schematic 253930. The preampli- fier output is applied to 3201. an analog outp”t at the rear panel, and fo X213. R213 and R404 (on Sehemstie 25392E. near S401A Deck No. 8) attenuate dc signals to the 0.91-volt level corresponding Co 1 “Ok full range. Note chat the positive terminals of QA202 and QA203 are essentially at LO. thus the feedback loops around each op-amp rend LO constrain the neSsri”e inputs also to the LO level. Since terminals 3 and 16 of RN.01 are connected to these ne&ati”e inputs, we may consider the IO-kilobm ele- ments connected co terminal 2 88 a siwle 5-kilOInn element to LO. The 5 kilohm element from Le”r.i~Ul 11 l .

5 kilohm equivalent element farm a divider such that rhe volta*e at terminal 2 of RN201 is half the voltage af. ceminal 1. For positive si&nals, the o"fpu~ of QA202 will *o negative. DZOl will be on, Q201 will be off. So if we define "2.~2 Z the outpur of QA202. "2 E rhe "olcage SC terminal 2 Of RmOl, "203 E the ourpur of QAZO,, "1 z rhe volra*e af terminal 1 of RN201 and also the preamplifier ourput; v203 = -2 W202) -2v2 where V202 = -2V2, therefore "203 - +4v2 -2Y2 - +2v2 - "1 For negative si&nals, the outwt of 98202 will *o positive. 1,201 will be off. Q201 will be on. In this case, the voltage at the o"tp"t of QA203 is -2 times the volCa&e at terminal 2 of RN201. Thus, From this. the ""ipolar OUtpUt at J202 pravides a positive signal equal in m*nitude to the value of the preamplifier output 5201. regardless of sign. For SC si&nals, Q&.202 acts as a full-wave rectifier, and QA203 as a filter "sin* C203. The avera*e value of the ac waveform appears at 5202 as 8 positi"e dc signal. Nate that Q201 is off for eosirive signals, on for negative signals. Thus the "polarity" line is HI for negative sipnals, LO for positive signals. This information is passed throu*h ewe tramisfms of QA201 and R207, and presenred to the logic on the Fl line on the right side of Schemaric 25393D. 3-9. A-D CONVERTER. (see Schematic 25393D). The unipo1ar output J202 creates a non-negative current in the 1-kilohm resistors between terminals 1 and 8 of RN202. This current is always applied to the ne*- aLive input terminal of i"Le*raLor Q.4204. If the diode between terminals 1 and 3 of QUO1 is off. this si*nal currenf. is Lhe only current applied to the integrator. If this diode is an, there is also a reference current at the Lnput node of the integrator. This reference c"rrent is determined from the -9 volt reference, the emitter-follower between terminals 6 and 7 of QA201, the 9-kilohm resistance between fer- minds 5 and 3 of RN202. and the setting of R205. The stare of the diode between terminals 1 to 3 of QA201 1s de~emined by the state of rhe CS-line corni"& from the LSI logic. If CS is high, terminal 3 of QA201 will be high, and the diode from terminals 1 to 3 will be off. Figure 7 shows ehe pertinent logic Fnternal to the LSI chip along with the cir- cufrry shown on Schemaric 253930 for the a-d converter. Note that LS will change state an rhe next clock pulse after TH has changed state. The state of TH is deter- mined by a zero-crossin* detector QA205 which follows the intekrator Q&204. For small inputs, the signal current makes rhe InLegraCor slowly ramp negative, un- til the integrator oucpuc CIOSS~S zero (see Figure 8). During this time, the reference current is off (CS 1s HI) .3"d 'TH is 81. When the integrator OUrpUt cr0**e* zero, 'IH Bees LO, and on the next clock p1use CS Will alSo go LO. This vi11 turn on the negative reference current Which Will cause the integrator LO ramp posi- tin? SC a much ‘aster rate (see Figure 9). 12 , v, - inregrstor output voltage. VA - threshold level of threshold detecror. FIGURE 8. Integrator Characteristics for Small Input Signals. If the input si*nal is very small. TH will *o HI im- mediaLely after the reference current is turned on, and at the next clock pluse, the reference current will he turned off. For large signals approaching end scale (2000 counts), when the reference current is off, the si*nal current will cause the inte*raror to ramp SC a faster rate in the negative direction bee Figure 10). when the reference c"IrenZ t"r"S on after sero crossing and a clock pluse, the dif- ference between the positive signal current and neg- arive reference current will be very emall since the

0"Cp"C voltage. v, - threshold level of threshold detector. PICURE 9. lncesrecor Characteristics for Full-Ran&a lnpuc s*gna1*. “0 “*.D” _---- __-- P 2.000CO”NTS -1 “0 - ince*racor c."CP"C "olca*e. "d - Chreshold level of threshold detector. FIGURE 10. lnCe&raCor Characrerisrics for End- Scale (2000 Co"ncs) Input Signals. reference cu==enC is set to be ,ust greater Ghan 2000 co""Cs. Thus. the inCe*=aCo= will slowly r‘amp in the posiCive direction. In Chin case, the reference CUT- rent is on most of Che Cime; TH and CS are LO most of the Cime. Near full range, Che reference current is on for 1 clock pluse and off for 1 clock pluse. 3-10. CLOCK. (see SchemaCic 255080). The clack con- sists of QA503, QA602, RSOZ Cbmugh X,505, and C503, at Che left edge of Schematic 255080. This *ene=aCes a low-duty-cycle 9.680 Hz clock for Che tSI lo*ic QA501. 3-11. LOGIC. (see Schemaric 25508D). QA501 contains all logic for the a-d conve=Ce= and auCoran*in* ci=- cuitry. Ran&e lines Rl, RZ, and R4 a=e conrralled eiChe= by the a"Ca=an*in* circuitry on QA5Ol o= by the range swirch S401B Deck No. 10. On manual ran&es, the MR line is connected CO LO which inhibifs the out- puts to Rl, R2, and R4 in the LSI cup, The *uncricm is selected by S4OI.A Deck No. 1. Table 3-3 indicaes the complete Crurh table for all functions and ran&es of the Model 165. Q&502 decodes Chis logic into con- trol lines far various relays and analog switches shown on Schmsti~ 255110. Also see SchemaCic 25392E. 1073 3-12. DISPLAY. (see Schematic 25394E). Q&501 &e”erates four m"lCiplexin* lines, T-O CO T-3, and each is hi&h for an 800 microsecond CLme interval. Durink T-O the, the funcrion is indicsred by DSlOl Chrou*h.OS107, and the polarity and most si*nificanC 1 are displayed by LED DN103. During T-l, T-2, and T-3, DN104, DN105, and DN106 =especCively display the numericaL digifs with decimal p"inCs. 3-13. POWER SUPPLY. (sea Schemaric 2539X). 5302 end 5303 select the appropriate primary combinations for the line volCa*es indicated. The outpur of ~301 and C301 is a + 10 volt unre&uleced su,qaly used fo= the display md for the +6 volt supply QA410 (see Schematic 25392E). Q&301 &e."erac~s a regulated +5 volt supply. This powers TTL. LSI, end some analog circuitry. 9.002 re&ulatos Che ""Cp,,C of D301 and D302 CO -12 volts. 5301 provides a mes"8 of dis- connecCin& Che power supplies so ChaC Chey may be tested independently from the logic and analog ci=- cuicry.

SWlll SW13/ SW14/ SW151 'unctian F4 F2 Fl U"W R4 K2 Kl K401 K402 K403 Q408 K404 K405 K406 K407 K408 K409 K410 K411 K413 K414 K415 - +ocv 0 0 0 lots" 0 0 0 1 0 0 1 0 0 __ _- -- -- -- -- -- -_ -- -DC" 0 0 1 107s" 0 0 1 1 0 0 0 1 0 __ _- -- -_ _- __ -- __ -_ AC" 0 1 0 lam" 0 1 0 1 0 0 0 1 0 __ -_ _- -_ -- -_ -- __ -- loom" 0 1 I 1 0 8-J 0 1 0 __ __ _- __ __ -_ __ __ -_ 1" 10 0 1 0 0 0 0 1 __ __ _- -- - -- -- __ -_ 10" 1 0 1 0 1 0 0 1 0 -- _- _- -- - _- -- - -- 100 Y 1 1 0 0 0 1 0 1 0 __ __ __ -_ __ -_ _- __ _- lKv111 0 0 1 0 0 1 -_ -_ __ _- __ -- _- -_ __ ACA 0 1 1 1OOUA 0 0 0 - 0 0 0 10 0 0 0 1 0 0 0 0 0 lOO"A 0 0 1 -- 0 0 1 0 0 o,o 0 1 0 0 0 0 0 100"A 0 1 0 -- 0 0 10 0 0 0 0 1 0 0 0 0 0 1OOllA 0 1 1 -- 0 0 1 0 0 0 0 0 1 0 0 0 0 0 ImA 1 0 0 -- 0 0 10 0 0 0 1 0 0 0 0 0 0 lOmA 1 0 1 -- 0 0 10 0 0 1 0 0 0 0 0 0 0 look4 1 1 0 -- 0 0 10 0 1 0 0 0 0 0 0 0 0 1.4 1 1 1 -- 0 0 0 1 0 1 0 0 0 0 0 0 0 0 +DCA 1 0 0 1LlA 0 0 0 -- 0 0 0 10 0 0 0 0 0 1 0 0 0 -DCA 1 0 1 lll.4 0 0 1 -- 0 0 0 10 0 0 0 0 0 1 0 0 0 lOUA 0 10 -- 0 0 1 0 0 0 0 0 0 1 0 0 0 0 1OO"A 0 1 1 -- 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1mA 10 0 - 0 0 10 0 0 0 1 0 0 0 0 0 0 1omA 1 0 1 -- 0 0 10 0 0 1 0 0 0 0 0 0 0 lOOm.4 1 1 0 -- 0 01 0 0 1 0 0 0 0 0 0 0 0 1A 11 1 - 0 0 0 10 1 0 0 0 0 0 0 0 0 omfs 1 1 0100n000 - 0 0 10 0 0 o-o 10 0 0 0 0 1m 0 0 1 -- 0 0 0 1 0 0 0 0 0 1 0 0 0 0 1oK.n 0 1 0 -- 0 0 0 1 0 0 0 0 0 0 1 0 0 0 1OOKn 0 1 1 - 0 0 0 1 0 0 0 0 0 0 0 1 0 0 M 1 0 0 -- 0 0 0 1 0 0 0 0 0 0 0 0 1 0 1Om I. 0 1 -- 0 0 0 10 0 0 0 0 0 0 0 0 1 lOoK 1 1 0 -- 0 0 0 1 0 0 0 0 0 0 0 0 0 0 1oOm 1 1 1 -- 0 0 0 10 0 0 0 0 0 0 0 0 0

Keithley accessories can be used with the Model 165 co provide additional convenience and Versatility. 4-3. MODEL 1651 SO-AMPERE SHUNT. The Model 1651 pic- tured in *igure 11 is an opLiona1 acceesory chat ex- pands the ac and dc current measuring capability of the 165 from 2 amps to 50 amps. The 1651 is a 4-ter- minal 0.001 ohm flX shunt that is connected externally to the 165 input terminals. The 165 is operated in the ac or dc volts mode manually on the 10 m,.Ui"olc and 100 millivolt ranges or in the AUTO mode for the convenience of automaric ranging. The voltage drop y:"'" the 165 inpuf, "sing the 1651 shunt is very - only 10 mLllivolce at 10 amps. The Model 1651 18 approximately 6 inches long, l-114 inches deep, and l-3/8 inches high. and may be m&nred t., a hard surface using the 15/64-inch diameter mounting hole an,either end of rhe shunt. A cable is provided to ~omect the input terminals of the Model 165 to the inner voltage-sensing terminals of the shunt. TNa cable is ap,mximaCely 58 inches long. The outer current-sensing terminals of the shunt should be used to connect to the c"rrenf source. FIGURE 11. Model 1651 SO-Ampere Shunt. 4-4. MODEL 1653 RACK NOUNTINS KIT. The Model 1653 picfured in Figure 12 is a single rack mounting kit which converts the Model 165 from bench maunt.ing to standard 3-112 inch x 19 inch reck mounting, with 15 inches (300 mm) depzh behind the front panel. a. Parts List. see Table 4-1. TABLE 4-1. Model 1653 Parts List 1 ItaCk Mo"nfi.ng Panel 2 2532gB 2 Bottom cover Bracket 1 25543B 3 Side Bracket 2 25330B 4 #6-32 x l/4 LG PHIL PAN km SCREW 2 __ 5 1110-32 x 3/g LG PHIL HD SCFlEW 4 __ / b. Insrallarion. Rack Mounting Panels and Side Brackers used in the 1653 are inrerchangeable. Using the four 1110-32 screws provided, mount one Rack Mount- ing Panel to each Side Bracket as shown in Figure 12. "sing the two 116-32 screws provided. mount the Boffom Cover Bracker berween the LWO Side Brackets. Place the Node1 165 inside the assembled rack kit, spreading the Side Brackers.co fit around the instrument. The curved and cusNoned back end of each Side Bracket fits around and into the rear-panel edges of the 165. The 1073 inside edges of the Rack Mounting Panels fit around the front-panel ednea of the 165. Now mo"llL the entire sss&bly of-the 1653 and 165 in a 19-inch. tidth rack. I FIGURE 12. Model 1653 Single Rack Mounting iat. 15

Recommerded test equipment for verifyin* performance end calibrating the Model 165 is given in Tables 5-l and 5-8 reepec- tlvely. Teat equipant other than that recommended may be substituted if the specification,, in the equip- ment tables are equalled or exceeded. These spscifi- cations are the minimum requireme"ts. 5-3. PERFORMANCE VERIFICATION. The purpose of this procedure is CO verify that the instrument is witbin specifications at the time end environmental condi- tiorls under which tile procedure is executed. If veri- fication is performed at a temperature other than the calibration temperature of 20 to 30°C, the specified temperature coefficient (correction factor) multiplied by the tem9erature difference must be added to the reading tolerance 88 indicated in Tables 5-2 through 5-7. Relative humidity should be less than 60%. If it is desired to insure that the Hadel 165 will stay within specifications for a period of six months, it is reconmended that the calibration procedure of Para- graphs 5-4 be used. a. Readinn Tolerance end Interpolation. (see Tables 5-2 through 5-7). A soecified reading tolerance with a" intege; number of digits allows a display reading with a steady indication or a" occasional + and - one digit. For example, a K? digit tolerance on a display reading of 1.000 allows a steady reading of 1.002 (or 0.998) z a 1.002 with 8" occasional display of 1.001 and 1.003 (or 0.998 with a" occasional display of 0.997 and 0.999). A specified reading tolerance with half digits allows a d-play reading with flashing between t"o ad,acent digits. For example, a Q.5 digit to1- erance on a display reading of 1.000 sllows a display chat is flashing between 1.002 a"d 1.003 (or 0.997 and 0.998). b. Preliminarv Setup. 1. Set the rear panel line switches for the pro- per yawer line (mains) volta*e that is available. Connect the power cord (CO-7) to the line. 2. Check the fuse on the rear ,,anel for proper rating: 9D-110,105-125 "AC: 1/4A, SLC-*LO, 3AG, Keithley W-38 195-235.210-250 "AC: l/g& SLC-BLO, 3AG, Keithley N-20 3. Connect the shorting link an the front panel berween the LO and GM) terminals. For maximum apera- tar safety, make certain that the front end rear panels and internal chassis shield are connected to '. earth *round by way of the third-conductor on the .: power cord or by way of a separate clip lead from the GND terminal'to earth ground. MAINTENANCE 4. get the front-panel power switch to ON and allow the Modal 165 to stabilize at ambient tern- perature for at least two hours. C. Zero Verification. Table 5-2 shows the allow ccl tolerance of zero oo- all ranges. Manually select function arid range on the 165 as indicated in the table. d. DC Volts Vsrificstion. (see Table 5-3). The - DC "oltege Source CA) is used directly for the 1 volt CO 1000 Volt ranges. For the 1oOmv and 1Omv ranges, 1 volt from the DC Voltage Source (A) is divided by B ratio of lo:]. and 1OO:l respectively using the Volt. age Divider (*), For cm"eaieace, it is tecommendad that the tasts of Table 5-3 be done in the eutorsng- in* mode. They may also be done in tba manual range mode. Verification should be made far both 90siti"e and negative iuputs. Table 5-3 indicates the allowed rending tolerance. equivalent settings, B"d tempera- ture coefficient. 8. AC Volts Verification. (sea Table 5-4). In I this procedure, the AC "olta*e Source (C) is used for: the 10 millivolt through 500 volts ranges of the 165.# Required so"rce accuracy is given in Table 5-4. ZOHS! "erificatioa is indicated only far the 1 volt range. This may be done on other ran*es if desired, but it \ is "ot necessary in that the same circuit components : are used on all ranges. Use the autaraa*in* mode ( for convenience or use the manual range mode. i f. DC Am!as Verification. (see Table 5-S): The DC Current Source (D) is used for the 100 microamp through 100 milliamp ranges. The 1000 milliamp range may be verified at the 100 millismp level, since both the 100 and 1000 milliamp ranges use the same sensing resistance. For the 1 and 10 microamp ranges, DC Volta*e Source (A) and DC Current kesietors (E) are used to develop the appropriate test currents. Set- tings for the DC Voltage Source (A) and the resistsnc box called DC Current Resistors (E) are. give0 in Tab15 5-5. Bath positive and negative currents should be verified. A"toran*in* is sug*ested for convenienca, except an the 1000 milliamp range where it is neces- ssr‘y to use the manual range mode. The manual mode my be used on all range tests if desired. . g. AC Amps Verificstion. (sea Table 5-6). It is not necessary co verify all ac amps ranges at a11 i frequenciee, since the same sensing resistors are also, used on dc amps, and the frequency response has been i already verified in Paragraph S-38. It is suggested , that AC Current Resistots (F) be 0.1%tolerance metal-: film resistors. used with AC Voltage Source (C) to develop the required ac currents. Tba resistors 1 should be located right e,t the front-panel input t terminals to the Model 165 so that cable capacity i does not contribute to ac current errore. Ideally, i the lo-kilobm and 1OPkilohm resistance values should also be shielded. Depending upon the en"ironmant in which the test is made, this may not be necessary. 16

in order to verify et least one point a" every range, and t" mi"it,ize extraneoue error8 in the source current due to the effects mentioned above. A"torangi"* is *"*geeted on all except the 1000 milliamp end 100 mill,.amp rangea. where the msnual range mode must be used. The manual mode may be used on all range tests if desired. h. ohms Verification. (see Table 5-7). The Resis- tance Source (0) is used for all ,,hms ranges of the 165 through the lo-megohm range. A discrete 100-m*- ohm resistor, Resistance Source (H) is used for the loo-megabm r*n*e. On this range, the sensitivity of the 165 is 1 pA per digit. Ideally, the lOO-megchm resistor should be shielded to avoid electrostatic pickup. However. it is possible to verify this range without grounded metal shielding araund the resistor. if care is used not t" rove anything around in the vicinity of the 10~me*obm tesistance, creating small electrostatic c"rre"ts. Again, *"t"r*"gi"g is sug- gested for convenience, although manual ranging may be used throughout. i. 1mA Verification. The lmA eurrem source fea- Cure of the Model 165 my be vertiied "sing the fol- 1aving procedure: 1. open-circuit the input teminals on the front panel; I MAmTENANCE 2. set the functia" switch co DC AWS; 3. Set the range switch to AUTO; 4. depress the ImA pushbutton; the display read- in* should be between +D.9 and +l.l millimp; 5. eet the function switch t" DC VOLTS; 6. depress the ImA pushbutton; the display read- in* should be bet"ee" +3.80 and +5.00 volts. j. Voltage Burden Verification es a" Ammeter. The "olta*e burden for both SC and dc amps may be verified by using the follotig procedure on DC AMeg function: 1. connect the DC Current Source (0) to the input terminals of the 165; 2. set the f""ct*o" switch co DC AMPS; 3. eet the range switch to AUTO; 4. CD""ect the DC Digital Voltmeter (I) to the Model 165,i"put temi"als in parallel with DC Cur- rent source CD); 5. Apply *lo0 millimp dc from the DC Current source CD). The DC Digital Voltmeter (I) should read less than 30 milli"olts. TABLE 5-l. Perf"rma"ce VeriflC*tiO" Test Equipment Ifem Description SpeCific*tiO" Mfr. MOdel A Voltage Source, DC +0.005x Fluke 33308 B Voltage Divider to. 005% ES1 SRlOlO ,~ C Voltage Source, AC (AC Cslibrator/Amplifier) see Table 5-4 Hewlett-Packard 745AI746A D Current Source. DC to.osX Fluke 3330B E current Resistors, DC fO.OlZ General kadio 1433Y F current Re*i.tors. AC lk", t O.lZ, 1/4w lOk0, * O.lZ, 1lSW look*. t 0.1%. 1/m __- mete1 film 0 Resistance source ?O.OlZ General Padi" 1433Y H Resista"ce source 1oowi. * l%, 2w --- --- I Digital Voltmeter, DC loom" f.S. *t f(0.U rd* + 0.1x mg) Keithley 160, 163. or 165 1073 17 t x

MAINTENANCE TABLE 5-2. zero "erifxcation MODEL 161 Input state FunctLon 165 Rang Display Readin* Reading Temperature Tolerance Coefficient shorted DC Volts 10 In" 100 rn" 1" 10 " 100 " 1 k" 0.00 i2 digits 00.0 fl ,000 +1 0.00 fl 00.0 fl 000 21 to.25 di*it/'C AO.1 HI.1 *0.1 *o. 1 *0.1 shorted AC Volts 10 mv 0.00 4 duits kO.1 digit/T 100 rn" 00.0 2.5 *0.1 1" . 000 2 *0.1 10 " 0.00 2 fO.l 100 " 00.0 2 fO.1 500 " 000 2 *0.1 open DC Amps 1 VA * 000 *3 digits to.2 digitl'c 10 VA 0.00 t-3 *0.2 100 PA 00.0 f3 i0.2 1mA . 000 33 *0.2 10 mA 0.00 i3 to.2 100 * 00.0 f3 io.2 1 A 000 *3 to.2 w- AC Amps 100 pA 00.0 4 di*its to.2 digiC/~C lm.4 . 000 4 20.2 10 mA 0.00 4 20.2 100 DlA 00.0 4 ?0.2 1A 000 4 *o.i shorted OhSIS 100 n 00.0 2.5 digits *0.1 dkgiC/'C lkn . 000 1.5 *0.1 10 M 0.00 1.5 to.1 100 kR 00.0 1.5 to.1 1MR . 000 1.5 *0.1 10 nn 0.00 2 *0.1 100 Ma 00.0 2 to.1 TABLE 5-3. DC-Volts "er*ficatio" DC Valta*e "oltage 165 DiSPlSY Rending source (A) Divider (8) Temperature R8"ge Reading Tolerance Coefficient 1" 1" 1" 10 " 100 " 1000 " 100:1 10:1 -_ __ __ -- 10 rn" 10.00 100 rn" 100.0 1" 1.000 10 " 10.00 100 " 100.0 1000 " 1000 to.35 t3 di*its di*itj°C +2 *0.2 12 *0.2 12 to.2 t2 M.2 +3 *c.2 18 1073 T - ,‘

ReSiStOr. (E) Range ReadiD* Tolerance Coefficient 10 MO 1 or* *1.000 *6 digits *0.4 digit/v 1 MO 10 "A tlO.DD *b Lt0.L +100 II* -- 100 &4 *loo. ,O 16 f0.4 *1 mA --- 1mA t1.000 '6 f0.4 *lo IL4 -- 10 mA flO.OO f6 20.4 *loo * -- 100 * *100.0 t6 *0.4 so0 m.A -- 1A *100 i3.5 *0.12 TABLE 5-6. *c-Amps "erific*tio" AC Voltage Source (12) 0"tP"t Prequency AC Current Resistors (F) tinge Display Reading Reading Tolerance Temperscure Coefficient 10.01" 20 Hz 100 k" 100 "A 100.0 *13 digits to.4 digit/-C -29 10.01 1kHZ 10 kG ImA 1.000 *13 to.4 10.01 2okHz 1 lm 10 * 10.00 +13 io.4 -29 10.01 1kHZ 1M 100 r&A 10.0 k4.5 io.22 10.01 1kHZ 1kR 1A 10 *4 fO.2 TABLE 5-7. ohms verification source 165 Display Reading Temperature Resistances (G&H) Range RWding Tolerance Coefficient 1073

in Table 5-8. Test equipment other than thaL recommended mey be substitu- ted if the specifications io the equipment table are equalled or exceeded. These specifications are the minimum requirements. Calibrared using the following procedure, the Model 165 Will stay hachin Bpecifica- tions for a period of 6 months for relative humidities up to 70% at 35’C (see specifications). I” Order to allow for aging B”d humidicy effects, the reading to1- ermce given in Tables 5-9 through 5-14 are the same or less ill** the tolerances given in Secfio” 5-3 Per- farmance Verification. If in verifying a” inetrument per section 5-3, it is found that all readings are WiLbi” the reading tolerances given in Tables 5-9 through 5-14, it is unnecessary to calibrate the in- strument. Calibration should be performed at come temperature from 20 co 3O’C at a relative humidity of less cha” 60%. a. Reading Tolerance and I”tecrx.latio”. (see Tables 5-9 through S-14). A specified reading tolerance with an infeger number of &its allows a display reading with a steady indication or an occasional + and - one digit. For example. a +2 digit r,olerance on a display readin% of 1.000 allows a steady reading of 1.002 (or 0.998) 0~ a 1.002 with an occasional display of 1.001 and 1.003 (or 0.998 with an occasional display of 0.997 and 0.999). A specified reading rolerance with half digits allows a display reading with flashing beewee” two adlacenr digits. For example, a f2.5 digit tol- erance on a display reading of 1.000 allows a display that 1s flashing between 1.002 and 1,003 (or 0.99) and 0.998). b. Preliminary Setup. Calibration should be per- formed at some temperature from 20 to 3O’C at relative humidity of less than 60%. 2. Check Ch@ fuse on the rear pane1 for proper rating: 90-110, 105-125 “AC: Lf4A. SLO-BLO, 3.G. Ketthley Fu-36 195-235, 210-250 “AC: l/8& SLO-BLO, xc, KeiChley FO-20 3. Connect the shorting link on the front panel between the LO B”d GNC rerminals. For maximum operator safety, make certain chat rhe front and rear panels and internal chaesis shield are con- nected to earth ground by way of the third-conductor a” the power card or by way of a separate clip lead from the GND rerminal to earrh ground. 4. Set the front-panel power ewttch to ON and allow the Model 165 LO stabllire at ambient tem- perature for at least two hours. 20 (C) to the HI and LO input terminals of the 165. Adjust Resistance Source (C) for 10 kilohms and y. set the 165 LO OHMS function in the AUTO range ’ mode. t b). Record the 165 display reading from step i a). Cl. Change the secti”& of Resistance Source : (Cl to 10 megohms. , d) . Adjust ealibrario” potentiometer R424 (see: rear panel) so that the 165 display reading is “ithi” one digit of the reading from step b). ; 4. Set the 165 to the DC “OLTS function and manually select the I-voLt range. Remove Ftesis- tsnce Source (C) and connect Shorting Plug (J) to the HI and LO input terminals. f). Adjust calibration potenriometer R434 (*et rear panel) BO that the display reading is 0 and the polarity sign flashes between + and -. z3). Hanually select the 10 millivolt range of the 165. h). Ad,ust calibrario” potentiometer R431 (sea rear panel) so that the display reading is 0 and the polarity sign flashes between + and -, 1). Repeat steps 8). through h). until all display readings are within the required tol- erances . 2. ““ipolar Amplifier and A-D Calloration. a). Connect the DC “ol~ege Source (A) to rhe input of the 165. set the DC “oltege source (A) output to -0.001 volr, wirh the 165 manually.~set to the 1 volt range. Adjust c*libraCio” Pot@“- ticmeter RZll (see rear panel) 8” that the 165 display reading is -0.001 volt without flashiw digits or with flaebtng equally becween -0.000 and -0.002. b). AdJust the DC “drag@ source (A) fO suppl: * -0.011 volt OutpUt. Record this 165 display reading. Reverse the O”ql”f polarity of rile DC Voltage Source (A) and adjust calibration poten- tiometer R204 (see rear panel) such that the positive and “e&ati”e inputs provide the same display reading on the 165, c). AdjusL the DC “oltage Source (A) to -1.911 Volt* output. AdJust calibration pote”tLome+Ar RZ05 (se. rear panel) 80 chat the 165 display reading is within 0.5 digit of rhe input. d. Zero Calibration Verification. Table 5-9 shows the allowed tolerance of zer” on all ranges. Manuall: select function and range 0” the 165 as indica‘ed in the table. If zero cannot be verified, repeat Para- grsphs 5-4Cl. If zero still cannot be verified, 1073

mode. Thy may also be done in the manual range mode. Verification should be made for both positi"@ and negati"e inputs. Table 5-10 indica- tes the allowed readine tolerance, equivalent settiwzs, and temperature caeffiEient. If dc &alrs cannot be - verified, repeat Paragraphs 5-4~. If dc volts still cannot be verified, consult Troubleshooting Section 5-5. f. DC Amps Calibration Verification. (see Table 5-11). The DC Current Source (0) is used for the 100 micraamp through 100 millimp ranges. The 1000 millimp range may be verified at the 100 millimp level. since both the 100 and 1000 milliamp ranges use the same sensing resistance. For the 1 and 10 micraamp ranges, DC Voltage Source (A) and DC Current Resistors (E) are used LO develop the appropriate test currents. Settings for the DC Voltage Source (A) and the resistance box called DC Current Resie- fors (E) are given in Table 5-11. Both wsitive and negative current8 should be verified. Autoranging is suggested for convenience, except on the 1000 milli- amp range where it is necessary to use the manual range mode. The manual mode may be used on all range teets if desired. If dc amps cannot be verified, consult Troubleshooting Section 5-5. of the 165 through the lo-megahm range. A discreet IOO-megohm resistor, Resistance Source 0%) is used for the 100~megohm range. On this range, the sensitivity of the 165 Is 1 p.4 per digit. Ideally, the 10'Smegohm resistor should be shielded to avoid electrostatic pick- . However, if is possible to verify this range with- E:t grounded metal shielding around the resistor, if care 18 used not to move anything around in the "ifin- ity of the 100~megohm resistance, creating small elec- trost*tic currents. Again, autoranging is suggested for convenience, although manual ranging may be used throughour. If ohms cannot be verified, repeat Para- graphs 5-4c. If ohms still cannot be verified, consult Troubleshooting Section 5-5. h. AC Calibration. 2. Set the AC Voltage Source CC) to 100 volts output at ZOkHs. Adjust calibration "ariable- capacitor C402 (sse Figure 13 and the bottom co"er of the 165) so that the 165 displays the same digits as recorded in step 1. Tolerance on this adjustment is to.5 digit. 3. Set the AC Voltage Source CC) to 10 volts ou~pur at ZOkHr and adjust calibration "ariable- capaciror C403 (ewe Figure 13 and the bottom cover 1073 !LU)ITESXKE ranges at all frequencies, since the same sensing re8ist.x. *re also used on dc amps. and the fre- quency response has bee" already verified. IL is suggested chat AC Current Resistors (F) be 0.1:: tolerance metal film resistors, used with AC Volt- age Source CC) to develop the required ac currents. The resistors should be located right at the front- panel input terminala to the Model 165 so chat cable capacity does not contribute LD ac current error*. Ideally, rbe IO-kilohm and IOO-kiiohm resistance values should also be shielded. Depending upon the environment in which the test is nade, cbir may not be necessary. The combination Of current rangee and frequencies given in Table 5-14 is sug- gested in order to verify at least one point on every range, and to minimize extraneous error-5 in the source current due LO the effecrs nenrisned above. Autoranging is suggested on all except the 1000 millimp and 100 millLamp ranges. where the manual range made must be used. The manuai oode may be used 0” all range tests if desired. 21 J .

-- mata film G Resistance Source ~0.01% General Radio 143x H Resiacance source lOohio. t 1%. 2w - - I Digital Voltmarer, DC 1oOmv f.8. at t(O.lX rdg + 0.1% mg) Keithley 160, 163, or 165 .I Shorting Plug use pure copper solid wire and dual ban*** plug Keithley K-7 (without copper ehort) 1073 23 c .:*

maximum allowed. not both simultaneously. For example. a reading tolerance of -0.00/L HFn. fo +0.00/l Max. indicates that the reading tolerance allowed is -0.00 occasionally flashing -0.01 OT +o.oo occasionally flashing +0.01. 24

100 10 Mn Mll 10.00 100.0 83.011 9.9213 10.07/8 116.9l117.0 TABLE 5-13. AC-Volts Calibratinn "ertiicatinn 10 nl" 1lrHz +0.142x 10 rn" 10.00 9.94 10.06 100 rn" lktk to.052 100 rn" 100.0 99.415 100.5/6 1Y l!dz *0.052 1" 1.000 .994/5 1.00516 10 " l!dZ *0.052 10 " 10.00 9.9415 10.0516 100 v lkH7. io.052 100 " 100.0 99.415 100.5/6 500 v 1kHZ s.032 500 Y 500 49617 50314 10 mv ZOkHZ ?0.052% 10 mv 10.00 9.82 10.07 100 mv ZO!dh io.052 100 mv 100.0 98.1 100.516 1v 2OkHZ *0.052 1" 1.000 ,981 1.005/6 10 Y ZOlcHl *0.052 10 " 10.00 9.81 10.05/6 100 " 20kHZ to.052 100 " 100.0 98.1 100.516 500 " ZOkHZ to.032 500 " 500 486 50314 1" 20 Hz +o. 15% 1" 1.000 ,982 1.005 *Reading tolerance can be minimum z maximum allowed. tmt bath simultaneously. For example. a readhg tolerance of -0.0011 Min. to +0.00/l Max. indicates that the reading tolerance allowed is -0.00 occasionally flashing -0.01 x +o.oo occasionally flashing +0.01. 1073 25 f %

(c) AC currem AC currem PiWLY PiWLY &&in8 T!dW.%W* &&in8 T!dW.%W* O"tD"C O"tD"C Pi-.X"e*CY Pi-.X"e*CY R.?IiBLOT‘B (P) R.?IiBLOT‘B (P) R.¶ttw R.¶ttw Raading Raading Ian. Ian. Max. Max. 10.01" 10.01" 20 Hz 20 Hz 100 k" 100 k" 100 II* 100 PA 100.0 100.0 97.7/E 97.7/E 100.7 100.7 10.01 10.01 lkH2 lkH2 10 kn 10 kn ,I&. ImA 1.000 1.000 .986/7 .986/7 1.01314 I.01314 10.01 10.01 zo!az zo!az I!6 I!6 10 WA 10 WA 10.00 10.00 9.7617 9.7617 10.07/s 10.07/s 10.01 10.01 1kKS 1kKS lkc lkc 100 mA 100 mA 10.0 10.0 9.6 9.6 10.4 10.4 10.01 10.01 1kHZ udiz 1kIl 1kIl 1A 1A 10 10 6 6 14 14 *Reading eolerance can be minimum x marimm allowed, not b0t.b atiltaneously. FOT ernmpla, a read *Reading eolerance can be minimum x marimm allowed, not b0t.b atiltaneously. FOT ernmpla, a readtng of -0.00/l xi,,. to +O.OO,l "ax. indicates that the reading eoLarance allowed Ls -0.00 occasioaally of -0.00/l Min. to +O.OO,l "ax. indicates that the reading .ZoLarance allowed Ls -0.00 oc~asioaally E +o.oo occasionally flashing $01. E +o.oo occasionally flashing $01. 26

I -T----L-- 28 FIGURE 16. Component Layout, Readour Board, PC-319. 0375 1 . .

ancei 20 Hz spec is OK. (h) only one digit is lit and at high brightness. wires near S4OLA Deck NOS. 2-5 have moved and/or RN403 is de- feccive. (1) C402. C403 out of ad,ustment . (2) wires near s4olA Deck NOS. 2-5 have moved and/or RN403 is defective. (i) All digits ha”62 iden- Defective aegmenr tica segments eirher logic. weakly UC or blank. U) one digit only has a Defective display. weakly lit or blank segment. (1) -12v and -6” supplies (1) Shore in -12” are inoperative; +10. SUPPlY. +5. +6” supplies are OK. (2) Defective 9.4302. Cm) +lO, +5. C6V supplies Short in +LO" supply. are inoperative; -12” and -6V supplies are OK. (3) Replace or clean Deck NO. 2 of s4oL4 or replace dama- ged relay(s). See Table 5-16 (c). Calibrate per section 5-4. R204 and RZll are controlling adjustments. (1) Recalibrate per section 5-4. (2) Paeieian wiree per Figure 14. (1) Check for 5X duty cycle 9680 k300 Hz waveform at pin 12, 13 of QA602. If "OC, replace Q.4503 or QA602. (2) 800 mi.crosec. 252 duty cycle pulses should appear on T-0 through T-3 multiplexin* lines. Replace q*501, QAlO4, and/or 9.4103. Check segment line (A through 0) for TTL level change at PLOZ, QA106 and QA107, PlOl. Replace apropriace component. Replace ON103, DN104, DN105, or DUO6 as appropriate. Check for Shorts in supplies; replace line fuse. (1) Look for mechanical short and remove. Wick, p,wer turnec off and 5301 disconnected, check for 3 to 5 kilohms at Pin D of P301. "se lOOmY f.a. ohmmerer Canocher Model 165) wick, circuit ‘0 connected to i.n~ue LO of defective 165. (2) Replace qA302. Look for mechanical ahmt and remove. With ps.,er turned off and 5301 disconnected, check for 100 to 200 kilohm ae Pi" E of P301. "se 1OOm" f.8. ohmmeter (another Model 165) witI3 circuit LO connected to input LO of defective 165. 32 1073 9 .

:c) DC AMPS and AC As5 GrelltCr than 12oov dc or oeak ac. (1) Greater than 12OOV dc. (2) treater than 1200" ac. Greater rha" 3 amps rms TIC. (1) Greater than 2oov rm.¶ ac, A”T0 range mode. (2) creacer than 250" rms or trigh volta.+/ high frequency on lower rang- es; manual range mode. (la) Q401. (lb) R420, R421. (la) c401. (lb) 0419. 0420 R405. R406. (la) PC Board tapes near 0401 through 0404. (lb) RN401. (lc) s4olA. oeck NO. 2. (la, Q405. (lb) QA402. (lc) 0414, 0415. (la) Check waveform ac a node of 0421 and 0422; it should not be il squarewave. check for 0ifficulty (a) in Table 5-15. (lb) Check R420 and R421 for darkening (heat damage) and/or cracking. If either is o?en, there will be no response to an input signal and high offset on the bottom ranges (la) Shorred or open. (lb) Check for response to input. (1~) Check for claq.Fn~ and leakage. (2a) Check R409, R414 through R417 for b.1:: tolerance. (2b) Check operation of K409 through k414. (2~) Cheek Q405, QA402, 0414. and 0415. 1073 33 P %

REPMCF.ABLE PARTS MODEL 165 SECTION 6. REPLACEABLE PARTS TABLE 6-1. Abbreviations and Svmbols Glass enclosed Carbon Llert7. (cps) IdlO (103) milli (m-3) Mefallized Polyester micro (lo-fJ) Metallized Mylar M~S (106) Manufacturer 34

(Reference Figure 18). Table 6-3 Chassis Parts List conrains d comprehensive switches, and details of rhe fronr and rear panels). lisriq of every part of the basic mechanical chassis See Paragraph 6-7 !lechanical parra LISL ior Parts "ot listed here. ILam Part DeScriptFon QU*lltity kitthy Required Parr NO. 1 TOP COVER 2 ASSEMBLY (with screen shield) 1 255348 spacers, Plastic 5 3 25355h Spacers, Rubber 5 4 ST-115 5 BOTTON COVER ASSEMBLY (with screen shield) 1 258808 Tilf Bail 1 6 255208 Feet, Plaseic, Black 4 7 Ball, Rubber 243228 4 8 FE-6 Screw, Slotted, Flat "d., 6-32 x 2" 5 __ 9 FRONT PANEL (less overlay) 1 10 253618 REAR PANEL 1 11 253898 Knob. Range 1 12 Knob, Function 25503~ 1 13 25504h Bushing. Lnsu1aror 1 25399A TO raw"* PC-318 from Bottom ccwer: 14 Screw, Phillips. Pan Rd., 6-32 x 5,16" 2 - TO rsmO"e PC-318 from rear panel: 15 Screw, Phillips, Pan "d., 6-32 x 5/16" 1 __ 16 Kc+ Nut, 6-32 1 - 6-6. ELECTRICAL PARTS LIST. Table 6-4 Circuit Designation Series cancains a list of the basic three-digit numbers of a series identifying la- cation of electrical (and mechanical) parts to a ~areicular printed-circuit assembly or assemblies. Reference is made to the manual pages (re&weable p*rc* liSC1 that contain all parts of a partfcular **k-i**. Followin Table 6-4 is a complete elec- trical parts list for the Model 165. Reference Table 6-2 to identify the sche,naric(s) pertain- Lng to a particular ~ri,,ced-~Lr~uit assembly num- her. 1073 TABLE 6-4. circuit Designation series series 100 200 300 400 500 600 O~SCriptiOtl Assembly No. Lo@ Board PC-313 Readout Board PC-319 "othm Board PC-318 Mother Board PC-318 Mother Board PC-318 Mother Board PC-318 Mother Board PC-318 1 35 -i .

"100" SERIES MISCELlANEO"S Circuit Mfr. Mfr. Kelthley LIesip,. Description Code 0e*ig. mrt NO. Of?. JlOl conwccor, 12 pins 02660 6-380949-Z cs-263 i JlO2 connector, 10 pins 02660 6-380949-O cs-264 2 5103 connector, 10 pins . . 02660 6-380949-O cs-264 2 PlOl Connector Pin, PC Board. 80164 --____ 2424% 29 PI02 Cmnector Pin. 02660 1-380953-O cs-265 20 PI03 Con"ector Pi". 02660 1-380953-O cs-265 20 CAPACITOR Circuit Mfr. nrr. Keirhley oesia. oescription Code Oeri~ Part so. qry. Cl01 100 &IF, ,10x, 15v, ETT 06751 TSD515107A c205-lOO'( I DIODES C‘rcu‘t Mfr. nrr. Keichley DSSi$. oescr‘ptio" Code Denis. Part NC3 c i' DlOl Rectifier. . . . . . . . . . . . . . . 01295 1N645 RF-14 17 0102 Fwctifis-. . . . . . . . . . . . . 0,295 1N645 RF-,4 17 0103 Rectifier. . . . . . . . . . . . . . . . . . . . 01295 IN645 RF-14 17 0104 Rectifier. . . . . . . . . . . . . . . . 01295 lN645 RF-14 17 0105 RecLifi.er. . . . . . . . . . . . . . 01295 IN645 RF-14 17 0106 Rectifier. . . . . . . . . . . . . . . . . . . . . 01295 IN645 RF-14 . 17 0107 Rectifier. . . . . . . . . + . . . . . . . 01295 IN645 w-14 17 DIODE NETVORK Cir‘C”it Mfr. Mfr. Keithley DSSiS:. O~SCriptiOll Code Oesig. Part NO. qiy. ON101 Diode Network, 14-pin DIP. . . . . 0726-S FSA2620M m-1 2 DNlOZ Diode Network, 14-pin DIP. . , . . . 07263 FSA2620" ON-l 2 ON103 Digital Display, PolarltylOverrsnge, 14-pin DIP. H-P HP5082-7732 DD-11* 1 DN104 Digital Display. 14-pin DIP, 7-segment . . . . . H-P HP5082-7730 DD-v* 3 ON105 Digital Display, 14.pin DIP, 7-segment . . . . . H-P HP5082-7730 Do-v* 3 oNlO Digital Display, 14-pin DIP, 7-segmenC . . . H-P "~5082-7730 DD-v* 3 *Selected for Light Intensity, Codes “C”, “I,“, or “E”. H-P = Hewlett-Packard 0375 37 s

“100” SERIES (cont’d) circuit Mfr. Mfr. Keithlay rlssizq. Description Code Desig. Part NO. qty. OS101 Pilot Lamp, 6.3V, T-1-3,4. . 05464 7381~AS25 PI.-59 7 OS102 Pilot Lamp, 6.3", T-1-3,4. . 05464 7381~AS25 m-59 7 OS103 Pilot Lamp, 6.3V, T-1-3,4. . 05464 7381-AS25 x-59 7 DSLO4 Pilot Lamp, 6.3V, T-1-3,4. . . 05464 7381~AS25 a-59 7 OS 105 Pilot Lamp, 6.3". T-1-3,4. , . 05464 73814525 x-59 7 DS106 Pilot ‘amp, 6.3", T-1-314. . 05464 7381-AS25 m-59 7 DSlO7 Pilot ‘amp, 6.3", T-1-3,4. . 05464 73814525 m-59 7 INTEGRATED CIRCUITS CirC”it Mfr. Mfr. Keiehley msig. DeSCfipttOn Code Dais. Part NO. qty. 9ALOL Transistor Array, 14-pin DIP . . . . . . . . . . 07263 FPQ3724 IC-63 I $4102 Transistor Array, 14-pin DIP . . . I . . 07263 PPQ3461 IC-57 2 QA103 Transistor Arr*y, 14-p‘" DIP . . 07263 FPq3467 IC-57 2 QA104 Hex Inverter, 14-pin DIP . . . . . . . 01295 SN7406 IC-62 3 QA105 Hex Inverrer. *4-pin DIP . . . . . 01295 SN7406 K-62 3 QA106 Quad NAND. 14-pin DIP. . . . 04713 "C858P K-22 1 QA107 Hex 1nverter, 14-pin DIP . . . . . 01295 SN7406 K-62 3 CiK”iC Mfr. Mfr. Keithley Keithley oesig:. oescriptio" Code DSSi&. Part NO. Part NO. .9rv. .9rv. RlOl 18 n.x.3w.w ................. 44655 4400-1m 30-1m RVZ-18 RVZ-18 i i RIO2 Not Used ............ : : ............................ _- RL03 680!?, LO%., L/f&l, Camp. ................ 01121 CB-331-10% R76-680 7 RL04 6803, LO%, 1/4W, Camp. ................ 0,121 CB-331s10% R76-680 7 RI05 6800, Lo%, 1/4w, camp. ................ 01121 m-331-10% R76-680 7 RlO6 6800, 10%. 1/4W, Camp. . . . . . . . 0,121 CB-33L-10% R76-680 R107 6800, lO%, 1/4w, camp. 01121 CB-331-10% R76-680 : RL08 man, 10%. 1/4w. Camp. . 01121 CB-331-10% R76-680 7 RLOV 68011, LO%, 1/4W, Camp. Oll2l CB-331-10% R76-680 7 RllO lk0, 10%. 1/4w. COW . . . . 01121 CB-561-10% R76-Ik 1 RESISTOR NETUIORXS Circuit Mfr. Mfr. Keithlay DesiR. Description Code Oesig. Part NO. qtv. RNlOl Thick Film Resistor Network. . , . . . . . . . . . . . 80164 -_---- m-11 1 RN102 NotUsed.............. . . . . . ----- _-__._ - -_-- _-. ..., RN103 Thick Film Resistor Network. . . . . . . . . . . 80164 --__-_ m-9 1 38 0375 i T .f

01121 G&105-10% R76-1M R210 Not Used. ....................................................... ..'. Fall lOK0, 0.75w, carmet .................. 73138 89P-10KR RP89-LOK 4 R212 2.8Kfl, l%, l/&r, MLF. ................. 07716 CEA-TO-Z.mn R88-2.8K 1 R213 6.04KR, 0.1%. l/&I, MtF ................ 91637 MFF-l/8-6.04K R176-6.04K 1

“300” SERIES circuit Desig. P301 P302 P303 3301 5301 S302 5303 F301 . . . . QA301 Qh302 ?,ISCEL~WEO”S Elf*. Mr. oescripeion Code oesip,. connector Pill, PC Board . 80164 war Used. . connector Pin, PC kJa*d 80164 Jumper connector ASSemblY . . . 80164 Switch, Power Toggle. 95146 "ST205N Switch, Slide, D.P.D.T. . 79727 GG35OPCDPDT S.,liLCh, Slide, D.P.O.T. 79727 GC350PCDPDT Transformer . . 80164 Fuse. Sh-*lo 1/4A. 117". . . 75915 313.250s Fuse, Slo-610 l/&4. 234". . . . . . 71400 MDL IntegraLed circuit, Voltage Regulator, w, case m-3. 12040 LM309K Integrated circuit, Voltage Regulator, 12”, case TO-220 0,263 UC”7812393 CAPACITORS CilZC”iC Mfr. Mfr. ^. _. n-34 K-60 c301 2000~F, 15", FAL. . . . C302 200 !JF, 35", EAL. c303 100 pF, 15”, EM.. c304 100 g, 15”, FAL. . c305 0.33uF, 50”, CerF . . . C306 0.1 pF. 16”. cero . c307 0.1 @, 16”, cero C308 0.33”F, 50", cerr . ......... 29309 JCN2000158P ......... 90201 mwOON35PDN ......... 29309 JC6100158P ......... 29309 iC6100158P ............ 72982 8131050651-344M ............ 71590 "K16-104 ............ 71590 "K16-104 ............ 72982 8131050651-334H DIODES circuie Mfr. nfr. Des‘R. OescriDLion Cc& oesig. 0301 Rectifier . . . . . . . . . . . . 01295 IN645 0302 ReCLifier . . . . . 01295 IN645 0303 Recrifier, Four-diode bridge. . . . . . . 83701 PO-10 1073 29 29 1 1 2 1 I 1 1 1 Ljry. c210-100x 2 c*37-,339 6 C238-.L'! 2 C238-.LY 2 C237-.33X 6

...... .8-8.5pF, 750", class. ........ ...... l.O-3OpF. 750", class. ........ ...... 6800PF, 1%. 100". Mica ........ ...... 97419 MZWX-.068M 72982 562-013 72982 568-013 14655 CD19FA68*F03 14655 97419 14752 14752 015FC641P03 MZWR-.0022M 625BlC-153 625BlC-222 CMI-.06&l C232-.8-8.5P C232-1.0-3OP C248-68OOP C249-6OP C181-.OLM C221-.015" C221-.0022M 56289 loss-510 C22-.OLM 6 17554 TSD210 cml-12OM 1 71590 m-330-10x C64-33P 2 29309 JC650158N C241-50M 1 72982 8131050651334M C237-.33M 71590 TCZ-3R3 c77-3.3P 71590 TCZ-3R3 C77-3.3P 72982 *0100ck5F0102K C64-.OOlM 56289 loss-S2O 56289 loss-s20 17554 TSD120125 72982 8131050651105M CISZ-.O22M C152-,022f.f 1 c179-1.2M c237-In 56289 loss-$10 C22-.olM 17554 To4015336-10 CZZB-33M 72982 81210506X-104M C237-1M 72982 8131050651-105M C237-.1M 72982 71590 56289 56289 80164 813105065133411 DD331-10% loss-910 lOSS-?I10 _- C237-.33M C64-33OP C25G.M C258-.LM C73-.0047M C404 C405 C406 C407 C408 60PF, 300", Mica ................... 0.01llF. 1200". .................... O.O15PF, 200", MPCb. ................. O.O022"F, 2OOY, MPCh ................. C409 C410 C411 C412 C413 C414 C415 C416 O.OlYF, 1000”. cero. ......... 120°F. lo", ETT. ........... 33PF, 1000", cero. .......... 50°F. 15", FAL ............. 0.33"F, 50'1, CerF. .......... 3.3pF, 600". CerT. .......... 3.3pF, 600". CerT. .......... .OOluF, 1000". CerD. ......... C417 C418 C419 C420 0.022UF. 1ooov. cerrl . . . O.O22PF, 1000". cero . . l.ZUF, 20", WC. . . . l.O"F, 50". CerF . C421 O.OllJF, lOOOY, cero. . . C422 33°F. 15". Epoxy . . . . C423 l.O,,F, 50". CerF . . . , C424 O.l"F. 50". CerF . . . . C425 C426 C427 C42R c429 0.33!JF, 50", ces. . . 330PF, 1000". ceto . . O.lvF, lOOO", CWD . . . O.liF, lOOO", cero . . 0.0047 F, 4OO", 20%. Mylar ....... ....... ....... ....... ...... ...... ...... ...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1073 'i .-I 42

0402 Reciifier 3.4, 200". . . . 0403 Rectifier 3A, 200". . . D404 Rectifier ,A, 200". . . . D405 D406 D407 D408 Rectifier, 75 mA, 75v Zener, 6". 4OOmW. . . . . NOf Used. . . . . . . zener, 9" . . . . . . D409 0410 D411 0412 D413 0414 D415 D416 D417 0418 0419 D420 0421 D422 D423 0424 D425 0426 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....... ....... ....... ....... . . . . . . . . . . . . . . . . , . . . . . . * . . . . * . . . . . . . . . . . . . . . . . . . ....... ....... ....... ....... ....... ..... : . ....... ....... . . . 9 . . . . . . . . . . . . . . . . . * . . * . . . ....... . . . . . . . . . . . . . ....... 06751 lN703A DZ-42 04713 "R1032B 04713 MK1032B 04713 E(R1032B 04713 km10328 RF-40 RF-40 RF-40 w-40 01295 IN914 12954 DZ701104A . . . . . . . . . . . 06751 18937 RF-28 DZ-47 . . . . . . . DZ-41 . . . . . . . . . . . 12954 lN715 12954 lN715 01295 1133595 . . . . . . DZ-22 m-22 RF-43 01295 lN3595 RF-43 01295 lN914 RF-28 01295 IN914 RF-28 12954 DZ701104A DZ-47 . . . . . . . . . . . . . . . . 04713 lN4006 RF-38 07263 lN3595 w-43 07263 lN3595 RF-43 01295 IN914 01295 lN914 01295 IN914 ..*.. . . . . . . RF-28 RF-28 RF-28 . . . . . 4 4 4 4 * 2 . . . . 1 . . . . 2 2 4 4 8 8 2 . . 1 4 4 8 8 8 . . . . . . 2 Ci*C”it Mfr. Nf*. Des<8 Description Code DSie.. Part NO. otv. K401 Single-Pole, N.O. .................. 70309 RI.-41 1 K402 Single-Pole, N.O. .................. 70309 a-39 4 K403 Single-Pole, N.0 .................... 70309 RI.-39 4 K404 Single-Pole, N.O. .................. 95073 375-670 FL-40 K405 Single-Pale, N.O. .................. 95073 375-670 u-40 K406 Single-Pole, N.O. . . . . ....... 70309 m-39 K407 Single-Pole, N.O. . . . ....... 70390 m-39 K408 Single-Pole, N.O. . . ....... 95073 375-670 m-40 K409 Single-Pole, N.O. . . . . ....... 95073 375-670 RI.-40 K410 Single-Pole, N.O. . . ....... 95073 375-670 RL-40 K411 Single-Pale, N.O. . . K412 NOf Used. . K413 Single-Pole, N.O. . K414 Single-Pole, N.O. . . . . K415 Single-Pole. N.O. . . . . . . . ....... 95073 375-670 RL-40 9 ........................... ....... 95073 375-670 RL-40 9 ....... 95073 375-670 XL-40 9 ....... 95073 375-670 Pa-40 9 0177 43 + .

"400" SERIES (cont'd) TRANSISTORS Q401 P-Channel MOSFET (Dual) . . . . . . . . . . . . . . 72699 955-004 TG-94 1 Q402 PNP, Case TO-106. . . . . . . . . . . . . . . . 07263 285910 TG-13.1 2 Q403 Not Used. . . . . . . . . . . . . . . . . . . . * . . . . . . . . . . . . . . . . . . . . . . . Q404 PNP, Case TO-106. . . . . . . . . . . . . . . . 07263 285139 X-66 1 Q405 NPN, Case 2N3439 K-93 1 Q‘06 P-Channel FET, Case TO-72 . . . . . . . . . . . . . . 72699 575-011 x-95 4 Q407 P-Channel FET. Case TO-72 . . . . . . . . . . . . 72699 575-011 TC-95 4 Q408 P-Channel FET, Case TO-72 . . . . . . . . . . . . 72699 575-011 TG-95 4 9409 P-Channel FET, Case TO-72 . . . . . . . . . . . . 72699 575-011 TG-95 4 9410 PNP, Case TO-106. . . . . . . . . . . . . . . . . . . 07263 2N5910 TG-111 2 QA401 Operational Amplifier, 8-pin DIP. .......... 12040 LM307N X-61 QA402 OFerarianal Amplifier. B-pin DIP. .......... 07263 Special X-76 t QA403 Operational Amplifier, [i-pin, Case TO-99. ...... 12040 LM31OH K-18 2 QA404 Amplifier, B-pin DIP. ................ 12040 IJ4301AN X-24 QA405 Amplifier, 8-p1n DIP. ................ 12040 LM3OLW x-7.4 : QA606 operational hlplifier, B-pin DIP. .......... 07263 Special XC-76 6 9.4‘07 Not Used. .......................................... Q.4408 NOL Used. .......................................... QA409 Operational Amplifier. a-pin, case TO-99. ...... 12040 u431011 X-18 2 QA410 Voltage regulator, 6". Cast 'TO-220. ......... 07263 UGH7806393 K-64 i RESISTORS R601 56OKR. 5X, 1/2W, Camp R402 SKJl, 0.75W, cermet. . . R403 IMn, l%, 1/2w, DCb. . . R404 6410, 0.1%. l/W. . . . R405 12.5Kn. 51, 3W, VW. . . R406 R407 R408 fl409* R410 R411 Ml2 R413 R414 R415 44 12.5w1, 5X, 3W. Ww. . . 30.1m, 0.1x, 3W, WW. . lrn, 1x, l/&J, MCF. . . 99.5n. 0.14, 1/8W . . . 1.2Krl, 10%. 2w. Camp. lli?, 1%. 1/8W, MS. . lrn, 1%. mw. NtP. 3.OlKn, 1%. 1/8W, MTF 9002, 0.1%. 1/8W. . . . 9Kn. O.l%, 1/2W, MU. , *Nominal value . . . . * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . * * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I * . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 01121 EB-56OKfi R19-560K 73138 89P-5m RP89-5K 91637 DCF-l/2-lMn RlZ-1M 91637 MMF-1/8-441n R176-441 15909 DAS3-12.5KR R208-12.5x 15909 DAS3-12.5KR R208-12.5K 15909 DAS3-30.1KR R207-30.X 07716 CEA-TO-1K.G R&9-1K 91637 Mm-l/8-98.7ri R176-99.5 01121 HB-1.2m P+l.ZK 07716 CEA-TO-1w R88-1K 07716 CEA-TO-1KR R88-1K 07716 CEA-TO-U5 Pm-3.0x 91637 NMF-ll8-9oon R176-900 91637 KFF-l/2-9KS R205-9K 2 1 2 1 0375 f b iI

.......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... .......... 4&18OK?i E&330!% CBTYZ-108 89P-1OKn CM-TO-825 CB-471-m): CBTYZ-108 CB-101-10% cw-1ooy*1 CB-39s10% 89P-1OKn CB-106-10): CEA-l.oKI1 89%1OKG CB-47*-10% m-47*-10% EB-560KZ CEA-6.8us CB-225-102 CB-22s10% CB-*72-iox CB-103-10% CL%-ll.0 CB-102-10): MIT-1,8-9W

91637 w-1/8-3oo.zcG R176-300.2K 1 R463 Zb.lKL?, 0.1%. l/W ................. 91637 MMF-l/8-26.1W RI,&26.1K 1 R464 3O.M?, 1x, 1/8W, MC. ............... 91637 MFF-l/8-3O.lW1 RZ06-30.N 1 R465 l.bZK.0, 1%. 1/8W. MU. ............... 91637 MFF-l/8-1.62KQ R206-1.6X 1 R466 lOw2. 10%. 1/4w, camp. ............... 01121 CL+103-101: R76-10K 6 R467 4.7Ki2, 10%. l/4!?, camp ............... OllZl CB-472-10X R76-4.7R 6 R468 b.wHr!, 1x, l/&l, Mm. ............... 07716 CEA-6.98m R88-6.98K 2 R469 4.99wi, I%, lftw, HtF. ............... 07716 cF.A-4.99KQ Km-4.99K 1 R470 lrn, 1x, l/N, MLF ................. 07716 CEA-1KR R88-1K 5 R471 R472 R473 R474 R475 R476 07716 CEA-lp-,, I@*-1K 07716 CEA-1w It**-llK 01121 CB-105-10X R76-1M 01121 CB-10s10% R76-10K 07716 CEA-4.ozm *88-4.0*X 07716 CEA-*KD X88-2K RESISTOR NETWORKS CirC”it Mfr. Mfr. Keirhley Desig. DesCriDtio” Code llesig. *art NO. QLY. RN401 Thick Film Resietors . . . . . . . . 80164 . . . . . . . . . . . R202 1 RN402 Notused...................... . . . . . . . ...‘..... . . . . . . . RN403 Thick Fall Resistors . . . . . . . . . 80164 ..,........ TF-II 1 46 1073 T .

c502 NOC USed ............................................... C503 O.OluF, 22, ZOO", >,ylar. ............... 14752 *1oBlc103-*% c*47-.01?! 1 c504 O.OluF, lOOO", CerD. ................. 56289 loss-SlO c**-.01.Y b c505 Not USed ............................................... C506 0.33-F, lOOO", cem. ................. 56289 lOSS-510 c*37-. 1% 6 C507 0.3,uF. 1000", tea. ................. 56289 loss-s10 c23:-.33!, 6 C508 470 pF, lOOO", cerrl. ................. 71590 m-471 C64-4iOP 1 circuit Mfr. ?(fr. Kefthley &sip. Description Code tIesif.. Part !:'I. it". @A501 Large Scale IC . . . . . 80164 LSI-2 LSI-2 1 QA502 Large Scale IC . . . . . . . . . . 80164 LSi-3 LSI-3 1 QA503 Timing Logic. &pill DIP. . . . 12954 1N709 IC-71 1 RESISTORS circuit Mfr. Mr. Lksig. Description Code Desig. 8501 2.2KO. 10%, 1,4 w, camp. ............... 01121 CB-***-10% 8502 12.7~1, 1%. l/8 W, MtF ................ 07716 CL-12.7KO R503 lKrl, 1%. l/.3 w, MCF ................. 07716 CEA-1K R504 4.7Kr2. 10%. l/4 w, camp. ............... OllZl CB-472-10% R505 4.7Kr2, 104, l/4 w, camp. ............... OllZl CB-472-10): R506 1K n, 10%. l/4 w, camp ................ 01121 CB-lo*-10% FL507 Not Used ................................... R508 47K.Q. 10%. l/4 W, camp ................ 01121 CB-473-102 Keithley Parc so. . Qt”. Rib-Z.?K 1 R88-12.7K 1 R88-lK 1 R76-4.7K 6 R76-4.7K 6 R76-1K 5 R76-47K 1 0177 . 47 7 .

. 71590 m-471 C66-47OP 3 C602 470 PF, 1000 ", CerD . . . . . . . 71590 m-471 C64-47"P 3 '2603 O.OluF, moo 'I, cer* . 56289 mss-SIO c**-.01‘1 6 C604 O.Ol>F, 1000 v, cem . . 56289 loss-810 c**-.01x 6 C605 O.OluF, moo v, cerl3 . . . . 56289 loss-s10 c**-.om 6 DIODES Circuit mr. er. Keirhley Desb?. Description CO& oesig. Part No. ijtv. 0601 Rectifier. . I . . , 01295 1N645 RF- 14 17 0602 Rectifier. . . . . , 01295 lN645 RF-14 17 0603 Rectifier. . . . . . . . . 01295 IN645 RF-14 17 0604 Rectifier. . . . . . . 01295 lN645 RF-14 17 0605 Rectifier. . . . . . . . . . 01295 lN645 RF-14 17 0606 Rectifier. . . . . . . 01295 lN645 RF-14 17 0607 Rectifier. . . . . . . . . . . . . . 01295 IN645 RF-14 17 Db08 Rectifier. . . . . . . . . . . . 01295 IN645 RF-14 17 DIODE NETWORK Circuit HfT. Mfr. Keithley ksir;. D~SC~iptiO" Code Desig. Part NO. Qty. DN6Ol 7-diodes, 14-pin DIP . . . . . . . . . . . ‘ 0726, FSA2620M DN-l 1 I Transistors CilT"iC Mfr. Mfr. Keithley Desis. oescrip~io* CO& Part NO. I oesin. OC". 9601 PNP, Case K-92. . . . . . . . . . . 0471, *mm37 W-61 3 4602 PNP, Case TO-42. . . . . . . I . . 04713 ZN5087 TG-61 3 INTEGRATED CIRC"ITS Circuit Mfr. Mfr. Keithl‘Zy Desig. ikscripcion CO&? Desiq. Part- NO. my. QA601 Hex inverter, 14-pin DIP.. . . . . . . . . . 01295 SW406 K-62 3 9A602 Hex inverter. 14-pin DIP . . 01295 SN7406 IC-62 , WO, Hex invercer. 14-pin DIP . . , . . . . . 01295 SW406 IC-62 3 RESISTORS R601 Not USed ........................................... ~602 22w, IO%, 1/4w. camp. ................ 01121 CB-223-10% R7b-**K R60, 47on, lO%, 1/4w, camp. ................. 01121 CB-471-N% R76-470 ~604 22x1, 10%. 1 /4!J. camp. ................ 01121 CB-223-10x R76-??K R605 li)K!!, 10%. 1/4w, camp. ................ 01121 CB-18510% R76-18K R606 ma, 10%. 1,4w. camp. ................ 01121 C&183-10% R76-18K 48 _. I 107,

1 - Kep N”f, 4-40 1 - Lug. solder 1 I,"-2 connector, Male, Line w.*"s) 1 m-254 Screw, Phillips, Pan Hd., 4-40 x 5/16" 2 __- Fuse Holder, for F301 1 FN-11 Hardware for w-313, Logic Board: Screw, Phillipa, Pan Hd., Self Tap. 2-56 x l/4" 2 _-_ Hardware for K-319, Readout Board: screw, Phillips, Pan Hd., 4-40 x 518" 1 __- "eat Sink, for QA-301 hIregrated CirC"it 1 "S-11 Hole Plugs. Plastic, for Bottom-Cover Ewce8s holes to c402 and c403 2 UP-18 Jumper. hmny Resiscar. for PC-318 1 J-3 Line (Mains) Power Cord SBL 1 co-7 Mounfing Kit. for Q405 *ranaiator 1 IX-6 Mounting NW., for s402 1 PA-59 Plate, Cover. Calibrarion Access 1 2534BA screw, Slotted. Round Hd., 2-56 x l/4" 2 _- *12se. cover @o"-acceas) 1 25388A Screw, Phillips, 4-40 x l/4" 2 --- Kep Nut, 4-40 2 --_ Readour Block, Film overlay 1 25544A Readout Block. Function (leas overlay) 1 25,388 Readout Display, Window. Prom Panel 1 25527.4 sbxcing Link, Input 1 BP-6 Socket, for DNl03, DN104, DN105, DN106 LED readout ~ispal,.s 4 so-70 Socket, 'B-Pin. for QA501. QA502 Integrated Circuits 2 So-69 spacer, Front Panel an* PC-Board 1 25358A Washer, Brass. for 5403 1 WA-S8 Washer. far D401. 0402. D403. D404 Rectifiers 4 WA-2 Washer, for S402 1 WA-65 1073