RCA AR-88.LF Instructions Manual

Montreal. Canada

Figure 2.—General Purpose Communications Receiver—Loudspeaker. 121

Page 1. General � 4 2. Technical Details � 4 3. Performance � 6 4. Installation � 7 5. Operation � 8 6. Maintenance. � 9 7. Vibrator Power Supply Unit (MI.22215) � 15 TABLES Table No. I---Performance Data � 6 Table No. II--Valve Socket Voltages � 9 Table No. III (a) � I.F. Alignment Connections � 10 III (b)—I.F. Alignment Adjustments � 10 Table No. IV (a) � R.F. Alignment Connections � 12 IV (b)--R.F. Alignment Adjustments � 13 Table No. V--Parts List, General Purpose Communications Receiver � 17 Table No. VI--Parts List, Vibrator Power Supply Unit � 21 ILLUSTRATIONS Figure 1 � General Purpose Communications Receiver----Front View � 2 2— CC � C6 � 44 � 46 �- -Loudspeaker .. � 2 3— 46 � 46 � CC � LC � Rear Apron ....... � . � 7 4— QC � 44 � CC � C6 � Alignment Layout . � 12 5— -Vibrator Power Supply Unit � MI-^2215 Schematic Diagram � 16 6--General Purpose Communications Receiver � Rear View . � 23 7— � 44 � ‘6 � 46 � 4, Top View � 23 8 � „ � Top View � Covers Removed � 25 * � 9-- � 6' � Bottom View � Covers Removed . 27 * � 10 � 44 � ---R.F. Unit . � ...... . .. � 29 * � 11 � 4, � ,, �- -ScheMade Diagram � 31 12— , � CC � 44 �--Selectivity Characteristics �33 13— " � " �" � Fidelity Characteristics � 34 14 � „ � 66 � Overload A.V.C. Characteristics � 35 *These illustrations are folded in. ERRATA Page 6 Paragraph 2.14 MI should read 22215. Page 7 paragraph 4.2 MI should read 22215. Page 12 Figure 4 C-96.0-97.C-98 Electrolytic condenser should read Oil Filled. Page 18 Table No. V C-96.0-97.C-98 Dry Electrolytic should read Oil Filled. {3}

INSTRUCTIONS 1. GENERAL 1.1 This receiver has been designed for general pur- pose communication. It is designed to withstand severe climatic and line voltage variations without appreciable impairment in performance. following features have been incorporated the design of this unit. Mechanical Band Spread, with Single Con- trol for ease of tuning a previously logged station. Automatic Noise Limiter which automa- tically limits interference to a percentage of modulation. Noise Limiter Switch for switching Noise Limiter on or off. Continuously variable High Frequency Tone Control. Panel Antenna Trimmer for circuit align- ment. Variable selectivity, with expansion of the normal selectivity characteristic for stand- by, and a crystal filter for ultra sharp selec- tivity when required. The crystal filter circuit is adjusted at the factory to give selectivity characteristics as shown in Figure 12. Temperature compensated oscillator circuits on all bands. Regulation of the anode voltage of the oscillator, giving good oscillator stability through normal' variations in line voltage. Four-ganged Condenser giving high image ratio, and very low oscillator radiation on all bands. Special screening devices have been built around the gang condenser, the master oscil- 2. TECHNICAL lator section, and the r.f. amplifier section in order to minimize oscillator radiation on all bands. (k) Tuning lock for service under extreme con- ditions of vibration. Frequency Range:— Band 1 � 73 to 205 KC Band 2 � 195 to 550 KC Band 3 � 1480 to 4400 KC Band 4 � 4250 to 12150 KC Band 5 � 11900 to 19500 KC Band 6 � 19000 to 30500 KC Sensitivity: � Better than 15 microvolts for 20 db signal to noise ratio, for MCW (A•2) reception and better than 5 microvolts for CW (A-1) reception (see table No. 1). Radiation:—Less than 40 micro-microwatts of power radiated, as dissipated in resistance con• nected from Antenna input terminal to ground. Value of resistance is such as to cause maximum power to be radiated (see Section 3 below). Output Power:—(Maximum undistorted) � 2.5 Watts when loudspeaker used. When low im- pedance headphones are used, maximum output fed to the phones is 100 milliwatts approximate- ly. Power Supply Requirements: � 115 or 230 volts, 25/60 cycle, 100 Watts or 6 volts D.C., 12 amps when external power supply MI.22215 is used. (Note—external power supply MI.22215 is only supplied when specially ordered.) Output Load:— This receiver has provision in the output circuit to take loads of 2.5 ohms, 20 ohms, and also low impedance headphones. Mechanical Specifications:—Overall Dimensions —191 inches wide x 11 inches high x 194 inches deep. Weight -- 100 Pounds (unpacked). DETAILS (see Section 4.4) with a conventional lead-in wire. The first tuned circuit is provided with a trimmer condenser adjustable from the front panel. This insures the proper tuning of this circuit with any antenna system. For all bands, conventional antenna and ground connections may also be used. The antenna terminal board is provided with three terminals (see Figures 3 and 7), two of which may be joined together with a link. When a single wire antenna is used, the link should he closed and the antenna connected to "A". If a ground is used, it should be connected to "G". 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.1 Circuit Details and Features:—The schematic diagram of this receiver is shown in Figure 11. It consists of two stages of R.F. amplification, first detector, first heterodyne oscillator; three of I.F. amplification, second detector and A.V.C., noise limiter, second heterodyne oscil- lator; A.F. amplifier stage, output power stage, and power supply system. 2.2 Input Coupling:—The antenna coupling system is designed to provide optimum coupling from a 200 ohm transmission line, but equivalent per- formance is realized with a straight line antenna [41

the link should be opened and the line con- nected to terminal "A" and the center terminal. Protection against damage due to high voltages across the antenna coil primaries is provided by a gas gap protector (Type 991 Valve). This protector will break down with an applied potential of approximately 50 Volts R.M.S. 2.3 R.F. Amplifier:--The R-F Amplifier is designed to provide ample selectivity ahead of the first detector for minimizing cross modulation and blocking effects from strong interfering signals and for obtaining a high degree of image signal suppression. The amplification is adjusted to provide optimum signal-to-noise ratio by making noise contributions of circuits following the first valve negligible in comparison with the noise contributed by the first R-F grid circuit; that is, each tuned circuit in the receiver contributes some noise voltage, but by making the gain of the first valve as high _as practicable, the noise contributed by succeeding circuits is unimportant. 2.4 Band Spread:--The mechanical band spread with single control knob enables the operator to tune quickly to a previously logged station. The log scale on the main dial and the separate ver- nier dial provide for exact logging and tuning. 2.5 First Heterodyne Oscillator: � The first hetero- dyne oscillator is aligned to track with the R-F Amplifier at 735 kc higher than the signal fre- quency, thus producing a 735 kc intermediate frequency in the first detector plate circuit which is amplified further in the I-F stages. The oscillator voltage is regulated by the Type VR- 150 regulator valve to provide maximum fre- quency stability under conditions of variations in power supply voltage. 2.6 Intermediate Frequency Crystal Filter: � The first detector plate circuit is tuned to the intermediate frequency and a balanced link circuit is used to couple the first detector plate and first I-F grid circuits. A 735 kc crystal is connected in one arm of the link circuit by the selectivity switch and a neutralizing capacitor is connected in the other. The impendance of the coils in the link circuit are designed so that the crystal selectivity characteristic is not impractically sharp. The band width at two times resonant input may be ad- justed to 550 cycles, 2000 cycles, 4,000 cycles, 8000 cycles, or 16,000 cycles. For this adjustment see "Operation". 2.7 Intermediate Frequency Amplifier: — Three stages of I-F amplification are used; Type 6SG7 valves are used in all stages and a Type 6H6 valve is used for AVC and second detector. The first I-F transformer has its primary and secondary tuned, and is coupled through the crystal filter link. The second and third I-F transformers are composed of four tuned cir- cuits each. These circuits are varied in coupling by the selectivity switch. The fourth I-F Trans- former has two tuned circuits. The third I-F stage is not connected to the AVC nor to the manual volume control so that a good AVC characteristic with little overload distortion is obtained. This also permits the CW oscillator to be coupled to the grid circuit of this stage, 2.8 Second Heterodyne Oscillator: — The second heterodyne (CW) oscillator is a triode Type 6J5 valve which is electrostatically coupled to the final I-F stage. A panel control is provided by means of which the frequency of the hetero- dyne oscillator and resultant audio beat note may be varied. Particular care has been taken in the design of harmonics. 2.9 � Automatic Volume Control:- -The AVC voltage is obtained from the second detector, a Type 6H6 valve. A variable delay is obtained depend- ing on the setting of the R-F gain control. The second heterodyne (CW) oscillator ex- citation voltage is just lower than the AVC diode bias voltage so that it does not decrease the sensitivity of the receiver. 2.10 Manual Volume Control:—Two manual vol- ume controls are provided: an audio gain con- trol which is employed when the AVC is in use, to obtain the desired output level, and an R-F gain control. 2.11 Noise Limiter:—The noise limiter circuit utilizes a Type 6H6 valve and limits the noise inter- ference to 100% modulation and to continuously lower percentages down to any modulation whatsoever, determined by the setting of the noise limiter control. A noise limiter switch in conjunction with AVC provides for use of the noise limiter on CW or on modulated reception when interference is present. 2.12 Output Valve: — The Type 6V6GT/G output valve is resistance coupled from the A-F ampli- fier, a Type 6SJ7 valve, and operates into an output transformer which has taps for matching into a 2.5 ohm load, or headphones. Terminals are provided on the rear apron for each of these load impedances. The output from the 2.5 ohm tap is fed directly to the 2.5 ohm output ter- minal, while the output from the 20 ohm tap is fed to the 20 ohm output terminal and also to a jack mounted on the panel. With the phone plug inserted into the jack, the phones are across the 20 ohm output and a load resistor, R-56, provides correct matching for the valve and reduces output supplied to the headphones. the circuit � minimize oscillator constants to [51

2.5 0,.„.„.5 0 ® 01/74/./7 Az e a 4 ® G (1400 Az) � O ; • / 99/ 7B. / \ ANT- GNO TER/1 BD. 3.3 Oscillator Stability:— (a) Oscillator frequency stable within 0.001% for line voltage variation of ± 5%. (b) Oscillator frequency stable within 0.003% for temperature change of 1°C. (c) Oscillator frequency stable within 0.001% for total variation of both the audio and R.F. gain controls. (d) Resetting of range switch from either direc- tion does not vary the frequency of the oscillator on any band more than 1 kc. 3.4 Dial Resetability � better than 2 kc. when the dial is reset from either direction, at any frequency. 3.5 Dial Calibration:—Calibration of the dial is accu- rate to within 0.5%. 3.6 AVC Characteristics: � The AVC circuit holds the audio output level to 15 db when the MCW (A-2) input is varied between 10 and 100,000 microvolts at any frequency, with any modula- tion percentage from 10 to 90, and with any modulation frequency from 300 to 4000 cycles. (See Figure 14.) 4. INSTALLATION 4.1 Power Supply:—The power supply circuit is integral with the receiver. Determine line volt- age and frequency and check with the rating of the receiver. The power transformer primary may be connected for either 115 or 230 volts 25/60 cycle by means of the toggle switch on the rear apron. This toggle switch is protected by a protector plate. To alter the connection of the primary, remove the protector plate, throw the switch, and replace the protector plate, with the reverse face out. 4.2 For Battery or Other Supply Operation:—For connections see Schematic Diagram Figure 11. It is only necessary to remove the plug from the socket on the rear of the receiver, and connect the batteries to the proper terminals as indi- cated by the schematic diagram. A battery cable terminating in an octal male plug is neces- sary for this purpose. If the Vibrator Power Unit MI.22216 is used, remove the plug from the socket on the rear of the receiver, and plug in the cable from the Vi- brator Power Unit. Connect the 6 volts D.C. input to the power unit with heavy, low resist- ance leads. See Section 7. for more detailed information concerning the Power Unit. 4.3 Valves:—Inspect the chassis before applying L./NE VOLTAGE ADJUSTMENT 51V/TCN TB 4 $ power to see that all valves are firmly seated in their respective sockets. 4.4 Antenna:—The input impedance at the antenna terminals is designed to match a 100 to 200 ohm transmission line or a straight wire capacity type antenna. For general use it is recommended that a straight wire antenna between 25 and 50 feet long be used for bands 3 to 6 inclusive, and a wire of 200 feet or more for bands 1 and 2. 4.5 Speaker:—Terminals for connection of a loud- speaker are indicated in Figures 3 and 7. The output transformer is designed to match a p.m. dynamic speaker having 2.5 ohms impedance. 4.6 Headphones:—A jack is provided on the left of the front panel for plugging in a pair of head- phones. If additional phones are required, they may be connected to the 20 ohm output ter- minals on the rear apron of the receiver. Phones having an impedance in the range of 100 to 600 ohms should be used. 4.7 Mounting:—The instrument may be placed on a table or mounted on a rack. For rack mount- ing loosen the panel mounting screws and re- move the front panel and chassis complete from the cabinet. Then mount on rack by means of the slots at the sides of the panel. ANTENNA CO/L /NOUCTANCE R CA- 1/00-97 ADJUSTMENTS Poe ALL. BANOS GA5 GAP PROTEr TOE - grosec) z-z(goec) 13 L -/t 0 (/0 9, 500 KC) WAVE TRAP [-a ria oder) 57 �0 - 8 � G//./.e CORO ,BELAY FOR BATTERY OPERAT /ON ETC. REMOVE PLUG,/` CONNECT BATTERY TO soct-Er(-/) Figure 3.—General Purpose Communications Receiver—Rear Apron [ 7 1 D/UE.eS/TY

information contained in this section should he thoroughly understood by the operator. The symbols on panel used to designate the various controls as shown in Figure 1, should be learned with respect to function, as described herein. 5.2 The Antenna Trimmer:-The center knob on the left is the Antenna Trimmer. Before tuning on any frequency range, it should be adjusted for maximum performance on the band. This control may be adjusted by tuning for maximum background noise. Occasionally it is desired to test a signal that seems out of place, to see whether or not it is a fundamental signal or an "image". When doing this, if the maximum signal point coincides with the point of maximum background noise, the signal is a fundamental. If the control does not affect the signal strength, or if it is a maximum at some other point, it is an "image". 5.3 The Main Tuning Dial is on the left and con- sists of a disc with seven scales, one for each of the six hands and a log scale. The two low fre- quency bands are calibrated in kilocycles and the other four bands in megacycles. 5.4 The Vernier Tuning Dial is in the center and has a scale with arbitrary calibrations for exact tuning and log records of particular communica- tion stations. It is used in conjunction with the log scale on the main tuning dial to give addi- tional figures for logging. 5.5 Power-Transmit-Receiver Switch: - This is a four-position switch. Starting from fully coun- terclockwise these positions are: 1. Power off. 2. Transmit position which gives energized tube filaments, open plate circuits, and shorted terminals (for transmitter relay) on the speaker terminal board on the back of the chassis. (3. & 4. on T.B.-2.). Connect relay to these two terminals for transmitter operation. (See Figure 3.) 3. Normal reception. 4. CW reception -- Beat frequency oscillator switched on. 5.6 Selectivity Switch: - This is a five-position switch and the band widths and control of selectivity are illustrated in the curves of Figure 12. The five positions are: 1. I-F band width for High Fidelity, modu- lated reception, - for "Stand-by" use. 2. I-F band width for normal modulated reception. 3. Crystal Filter in -- for CW telegraph or sharp modulated signal reception. 4. Crystal Filter in -- for sharper CW tele- graph reception. 5. Crystal Filter in -- for sharpest CW tele- graph reception. 5.7 Noise Limiter-AVC Switch: � This is a four- position switch and starting from the fully counterclockwise position these are: 1. AVC and NL out - Manual gain only -- for CW � no interference. 2. NL on, AVC out - Manual gain � for CW with interference. 3. NL and AVC on - for Modulated Recep- tion with interference. 4. AVC on, NL out -- for Modulated Recep- tion � no interference. 5.8 R-F Gain Control:-This continuously variable sensitivity control is for use in conjunction with the audio gain (Volume) control for all manual gain operation. With AVC on, it should as a rule he set to its fully clockwise position or may be turned to eliminate interference. For recep- tion of strong CW signals, it must he retarded somewhat. 5.9 Noise Limiter Control:-This control sets the instrument for operation at the required per- centage value of Noise Limitation. The fully clockwise position limits the noise interference to 10070 modulation. As the knob is turned counterclockwise, the noise interference is lim- ited to continuously lower percentages of modu- lation so that in the fully counterclockwise posi- tion the Noise Limiter is operative on any modulation whatsoever. Normally, the fully clockwise position will be used, but under ex- treme conditions of interference a balance point should be found for maximum intelligibility of signal with best modulation and least noise. 5.10 Tone Control:-This is a continuously variable control for reducing HF response. In the fully clockwise position the full tone is obtained and as turned counterclockwise, high tones are lessened. Set it to suit the particular tonal con- ditions for the signal being received. 5.11 Beat Frequency Oscillator Control: � This con- trol is normally used for CW code signals. It should be adjusted to give the desired audio pitch after the signal has been accurately tuned. 5.12 Tuning: � For functions of controls see the foregoing paragraphs. 1. Turn receiver on and set the Power- Transmit-Receive Switch for the required type of operation. 2. Set Range Switch for band required. 3. Set Antenna Trimmer for maximum back- ground noise. rs)

operating conditions — See Selectivity Curves � Figure 12. 5. Set Noise Limiter � AVC Switch for the required operating conditions. 6. Set R-F Gain Control fully clockwise. 7. Set Audio Gain Control about halfway. 8. Tune in the station. 9. Reset Audio Gain Control to give desired volume. 10. Reset Selectivity and Sensitivity (R-F Gain) Controls and Noise Limiter Control in accordance with requirements due to in- terference, station transmission, and other conditions. 11. Set Tone Control for preferred tone. 12. On CW (A-1) operation set Power-Trans- mit-Receive Switch to "Rec. CW" (position 4) and set BFO Control to give desired pitch. When a strong CW signal is being received, it is necessary to retard the R.F. Gain Control to reduce the volume. 13. If the receiver is subject to vibration, the tuning may be locked by turning clockwise the knurled screw directly beneath the tun- ing knob. Turning the screw moderately tight will lock the tuning. 5.13 Diversity Reception: — Provision is made to operate two or three of these receivers together for "diversity" reception. For this type of recep- tion the A.V.C. circuits of the receivers are tied together. The receivers are operated on separate antennas, and the receiver receiving the strongest signal, thus generating the greatest A.V.C. volt- age, dominates the other receivers. If the separ- ate antennas are faced to .the incoming signal at different angles, the good reception with mini- mum fading results. Refer to Figure 3: Connect together the ter- minals, marked "Diversity" of the receivers, and equip each receiver with a separate antenna. Tune each receiver to the same station as ex- plained in Section 5.12 above. 6. MAINTENANCE 6.1 This receiver should maintain its correct fac- tory adjustments over a reasonably long period of time. Causes of trouble and the probable sequency of their development arc outlined in the following paragraphs: 6.2 Valves:--A noticeable decrease in the sensitivity of the receiver usually indicates worn out valves. If the sensitivity is low, remove and check the valves in a reliable valve tester or substitute new valves one at a time. See Schematic Diagram, Figure 11. Valve socket voltages are given in Table II. TABLE No. II VALVE SOCKET VOLTAGES Valve � Symbol Type 6SG7 Plate Volt. Screen Volt. Cathode Volt. 1st R-F Amplifier 1 235 150 0 Type 6SG7 2nd R-F Amplifier 2 235 150 0 Type 6J5 Oscillator 3 110 0 Type 6SA7 1st Detector 4 235 50 Type 6SG7 1st I-F Amplifier 5 235 150 7 Type 6SG7 2nd I-F Amplifier 6 235 150 1.3 Type 6SG7 3rd I-F Amplifier 7 235 150 3.1 Plate Screen Cathode Valve � Symbol Volt. Volt. Volt. Type 6H6 2nd Det. & AVC. � 8 Type 6H6 Noise Limiter � 9 Type 6SJ7 1st Audio Amplifier 10 83 34 0 Type 6V6GT/G Power output � 11 256 240 0 Type 6J5 B.F.O. � 12 40 0 Type VR-150 Voltage Regulator 13 150 0 Type 5Y3GT/G Rectifier �14 300 NOTE � These voltages all measured to chassis. Measured with a 1000 ohm per volt meter. Variations of ± 20% may be expected due to resistance tolerances, etc. [91

tively on certain positions after long periods of inoperation. Usually rotating the switch back and forth several times will clean the contacts and operation will become normal. A bad range-switch contact is likely to cause a change in the sensitivity of the receiver, or the frequency of a received signal, as the switch is moved back and forth slightly in a certain fre- quency band position. A further check is to turn the switch off and on at one particular fre- quency band several times and note the apparent sensitivity of the receiver each time the switch comes into position. The sensitivity should be the same each time and may be adequaely judged for this test by listening to the receiver back- ground noise. 6.4 Circuit Alignment: WARNING:—The Circuit Alignment of this receiver has been done very carefully at the factory. and re- alignment should not be attempted unless it has been definitely ascer- tained that the Circuits are out of alignment. It should be attempted only by skilled personnel. It must be performed in a test laboratory where proper test equipment is available. All adjustments must be done very carefully and the exact procedure as outlined below must be followed. 6.4-1 Alignment Tools:—Special tools for align- ment of R-F and I-F circuits are provided. They are mounted in fuse clips on either side of the gang condenser cover, and are available after removing the large R-F unit cover. The shorter one of the two is for adjustment of all R-F and I-F coils, and the longer one is for adjustment of the plunger type trimmers. One end of this tool is for turning the lock nut on the trimmers and the other end has a hook for engaging in the hole in the end of the plungers. After adjustment, the lock nut should be securely tightened. 6.4-2 I-F Alignment:—The intermediate fre- quency is 735 kc. The only satisfactory method of I-F alignment is by means of a sweep oscillator and cathode ray oscillo- graph. The I.F. circuits must be aligned at exactly 735 kc, and the frequency of the sweep oscillator carrier must be checked against a 73.5 kc. crystal oscillator. Make connections as in Table III (a), and follow the sequence as in Table III (b). TABLE No. III (a) I.F. ALIGNMENT CONNECTIONS Vertical "HI" to Terminal C on last I-F Transformer (L-47, L-48), Vertical "LO" to chassis. Insert in series with generator output, 0.01 mfd. See Chart below. To Chassis. Band No. 1 Position 3 (Rec. Mod.) Fully clockwise. Position 2. Position 4 (AVC). Oscillograph Connections Dummy Antenna Connection of Generator Output Lead Connection of Generator Ground Lead Position of Range Switch Position of Power-Transmit-Receive Switch Position of R-F Gain Control Position of Selectivity Switch Position of Noise Limiter and AVC Switch TABLE No. III (b) I.F. ALIGNMENT ADJUSTMENTS (Alignment Frequency is 735 Kc) Steps Generator Connections Slug Adjustments (See Fig. 4) Trimmer Function 1 6SG7 • 3rd I-F Grid L-47, L-48 4th I-F Transformer 2 6SG7 • 2nd I-F Grid L-41, L-42, L-43, L-44 3rd I-F Transformer 3 6SG7 • 1st I-F Grid L-35, L-36, L-37, L-38 2nd I-F Transformer 4 6SA7 - 1st Det. Grid L-32, L-33 1st I-F Transformer 6.4-3 Align each transformer to give a symme- trical flat-topped curve on the oscillograph. Before performing step 4 above, set crystal phasing control C-75 at approximately one- half of its maximum capacity. This is ap- proximately its final setting and changing it appreciably will slightly detune the first I-F transformer. With Selectivity Switch in Position 2 the I-F band width is normal without over- [10]

tivity Switch in Position 1, the second and third I-F Transformers are expanded and over-coupled. It is well in going through tht alignment steps outlined above to check the I-F curves on the oscillograph screen with switch in Position 1 to see that the curves expand symmetrically. 6.4-4 Adjustment of Crystal Phasing Contrekh— This adjustment is best made by means of a signal generator and a high resistance sensitive DC voltmeter. Place Selectivity Switch in Position 3. Connect the gener- ator to the grid of the 6SA7 first det., and the Voltmeter to Terminal C on last I-F transformer (L-47, L-48). Tune the gen- erator to about 7 k.c. off I-F resonance and adjust the crystal phasing control C-75 for minimum response. If C-75 is adjusted much from its position as in Section 6.4-3, check alignment of first I.F. transformer. 6.4-5 Adjustment of Crystal Load Circuit:— Make connections as listed in Table III (a). (a) Place Selectivity switch in Position 3. Rock the signal generator frequency back and forth across the I-F resonant frequency and adjust the crystal load circuit trimmer L-34 or symme- trical round-top curve. (b) Place the Selectivity switch in Posi- tion 4, Rock the signal generator frequency and adjust trimmer C-81 for symmetrical curve. (c) Place the Selectivity switch in Posi- tion 5. Adjust trimmer C-SO rocking the signal generator as for (a) and (b) above. The above three adjustments are very critical and must be made carefully to ob- tain symmetrical curves. 6.4-6 Adjustment of Wave Trap: � A wave trap is connected across the No. 3 band, first R.F. primary to increase the rejection of I-F signal frequencies. With the range switch on Position 3, apply a modulated I-F signal to the antenna and ground terminals. Adjust the wave trap trimmer L-57 (See Fig. 3) for minimum output. The wave trap should be adjusted before the final R-F alignment on No. 3 band, or the R.F. coil alignment may be affected. 6.4-7 R-F Alignment:— A signal generator cov- ering a range from 70 to 550 kc and 1.5 to 30 megacycles, and an output volt- meter, are required. It is desirable to con- nect a speaker across the output terminals. The output voltmeter should then be con- nected across the speaker voice coil. The output impedance is 2.5 ohms. Remove the cover from over the R-F unit by loosening the four knurled screws and lifting off. Refer to Figures 3 and 4. Make connections as per Table IV (a). Align the R.F. circuits carefully, following the procedure as in- dicated in Table IV (b). Always align for maximum output. A correctly aligned re- ceiver should have performance equivalent to that described in Section 3. Replace cover after alignment is completed. 6.4-8 Adjustment of Beat Frequency Oscil- lator: � Tune in a signal either R-F or I-F to exact resonance with Power-Transmit- Receive Switch at "Rec. Mod" (Fig. 1.). Turn on beat frequency oscillator by turn- ing switch to "Rec. CW". If zero beat does not fall within the range of the BFO con- trol, adjust BFO Trimmer L-22 (see Fig. 4) until zero beat occurs at the mid-point setting of the BFO control. 6.5 Mechanical Construction:- 6.5-1 The receiver has been designed to be very rugged so that it will stand up under severe conditions of use, and yet have all parts available for easy replacement. All component parts such as transformers, chokes, filter and by-pass capacitors, etc., are mounted with screws and nuts rather than with rivets. All wiring other than that involving high frequency circuits is made up in the form of a laced cable so that no loose leads are left floating which might cause damage or change capacity to various portions of the circuit. The tuning condenser is mounted so as to be rigid with respect to the tuning unit, and yet is flexible with respect to the chassis. This prevents distortion of the chassis from having any appreciable effect on the sta- bility of the oscillator. 6.5-2 The R-F unit which consists of the tun- ing condenser, tuning unit, range switch, and all of the R-F and oscillator coils and trimmers, is mounted on a separate base which bolts to the main base. The various coils and trimmers on this base may he easily replaced by means of a single nut which screws on the individual mounting bushings. However if a major repair is to (Continued on page 14)

R.F. ALIGNMENT CONNECTIONS Output Meter Connections � Across speaker voice coil Dummy Antenna � See Table IV (b) below Generator Modulation � 30% at 400 cycles Position of Tone Control � Fully clockwise Position of Antenna Trimmer � See Table IV (b) below Position of Power-Transmit-Receive Switch � Position 3 (Rec. Mod.) Position of Range Switch � See Table IV (b) below Position of R-F Gain Control � Retard to reduce noise Position of Audio Gain Control � Fully clockwise Position of Noise Limiter and AVC Switch � Position 1 (Manual) Position of Selectivity Switch � Position 2 . ,. � „. � ., . - A ,,,,...,-, L-43 � L-42 �C-/9 42 6NNO � L -se ...3 BANG � C-25 . '4 BANG 1^ c,,,,-.-. - -c � Z-S4 � 4 4 6/94,0 (2- 44 BOTTOM �(2-4/ 847-50,7) � sso .ec /...9S-e ..., /e., -4 ./..ro KC 4 2 SO KC ,... � Z - SS � 4,5- N94.0 /4 900 KC C-47 g''S BAND L-29 ( ON ro.<) I � 1 3R0/F. /9, SOO KC Z-9.9 411) 3Ro /,e 79R0 / © C-/(5- � 4/ 6:94,0 ( L- 47 807-70,9) , � -, Or,v /F ,TRANS, \, TRAW.S., C, � Cil 20S KC 4-97 (L -3B 8057-0,,,) TRANS. Z-S6" 4C 6:94.0 /9, 000 KC • / � 0 , 0 00C a Z-96 (4 -3.0 BOTTOM) TRANS GI CO 4 1 110 Z-57 � "''/ 8,9,4,2, 79 KC C-00 � KC SO � 0 6:94/0 Lift, 242 /F 61.*-------------_____C-22 49 BANG 4000 KC S C- 32 ..6- fig/1W 90 SO 0 KC Z -.9 3 r L.- 3 2 BOTTOM) L-24 It L-26 2.0 OFT "Arc /2.ro./ s_ TRANS, r2N0 /FN TRANS ‘,. 63/97 Z-S9 49 NANO ,,,.g ea KC 0 C- 6B 44 6:940 80, 000 KC 42 BANG 805 KC NO/SE /ST .0S-7: 7-9/ � . 'cs- er:wo /9, 400 KC L-29 1 469 Z/A7/72-A. '-/S7 - A FN C9 C-64 43 8946e, 4,2SO KC 0....______-------- 0 C-S9 4/ 694/0 43 BRNO 1600 ..re /..5-r //7 r.e.4,vs to Z-27 yE. Z--28 /..9-1- A."C 4-49 0, Z-6/ tial /sr .4,7 6-S67 449,940 4 400KC z-escs,z-24, ......784,40 � 6-00 ""C VW CeYS c-62 .'48,9,yo 4900 KC 4/ BRNO BO KC --------------'eRfS'.-,• 8.c/ve, ''''' '--... L- eo � . s 8,4,4,20 . 4-94 CON 7-0,4,) 0e/7/04, LOAD 0 c_8/ J '44' � rOt .. , � 4 2S0 KC 0:, /2, /SO KC C.00 0 � , C-7S 5-/7 se L-A9 C-CC 4S 6:94/0 0-98 ."e BANG sac, ..--c Am' ...00.111P' 0 � fo .....„,,,, 446.9NO 4400KC .... C-9 4 89440 .9 01 � * / 9 000 KC L - SO fa //, 900 KC C-97 � 4/ 8,9,v0 r9_,- KC c- 7.5- CRYSTAL FYI TER /sr ,er- AN4S/416 CONTROL c,vo,e4- -2/ /9, SOO A." C Z-/S i z-.46 N 6 4 2 BRNO 80S KC 7= / C-4S � 8,9444 30,000 KC POIVE:E" 7-4,47 VS. cwaA-s VOLT 'PEG- S- Y3 � I/2 ST � /SO EL EC reaerr/c CONOEWSZe C-96 � C- 97 � C-96' 4-20 � ..`..,- 8/7.y2 ./-,, /SO KC Z-/-9 ,e Z-/.0 19 / 8.91/2,0 BO KC C- 49 � '''s- .5,94/S RECT /9, 000 KC Figure 4.—General Purpose Communications Receiver—Alignment Layout.

R.F. ALIGNMENT ADJUSTMENTS Position of Antenna Trimmer indicated. Max. output Untouched over the band. Range Oper- Switch ation Posi- No. � tion 1 � 1 2 � 1 3 � Repeat 1 and 2 4 � 1 5 � 1 6 � Repeat 4 and 5 Dummy Antenna 74 � 700 mmf 200 � 700 mmf until end frequencies are as 195 � 700 mmf 80 � 700 mmf until circuits remain in alignment Trimmer Adjust- ments for Max. Peak Output (See Figures � Trimmer 3 and 4) � Function L-51 � Low end osc. C-16 � High end osc. C-37, C-59 � 1st & 2nd R-F L-2, L-14, L-24 Ant. & 1st and 2nd R/F Po.jtion of Dial, and Generator Frequency 7 � 2 8 � 2 9 � Repeat 10 � 2 11 � 2 12 � Repeat 200 � 700 mmf � — �L-52 545 � 700 mmf � — �C-19 7 and 8 until end frequencies are as indicated. 500 � 700 mmf � Max. output 205 � 700 mmf � Untouched 10 and 11 until circuits remain in alignment over the band Low end osc. High end osc. 1st & 2nd R-F Ant. & 1st and 2nd R-F. C-38, C-60 L-4, L-16, L-26 L-53 C-?2 3 3 Repeat 3 3 Repeat 4 4 Repeat 4 4 Repeat 4,250 � 200 ohms 1,600 � 200 ohms 16 and 17 until circuits remain in alignment Low end osc. High end osc. Max. output C-41, C-64 � 1st & 2nd R-F Untouched � L-6, L-19, L-29 Ant. & 1st and over the band. � 2nd R-F. 13 14 15 16 17 18 19 20 21 22 23 24 1,500 � 200 ohms 4,350 � 200 ohms 13 and 14 until end frequencies are as indicated. 4,300 � 200 ohms � — � L-54 � Low end osc. 12,100 � 200 ohms � — � C-25 � High end osc. 19 and 20 until end frequencies are as indicated. 11,900 � 200 ohms � Max. output C-39, C-62 � 1st & 2nd R-F 4,400 � 200 ohms � Untouched � L-8, L-18, L-28 Ant. & 1st and 22 and 23 until circuits remain in alignment over the band. � 2nd R-F. *25 � 12,000 � 200 ohms 26 � 19,400 � 200 ohms 27 � 25 and 26 until end frequencies are as indicated. 28 � 19,000 � 200 ohms � Max. output 29 � 12,150 � 200 ohms � Untouched 30 � 29 until circuits remain in alignment over the band L-55 � Low-end osc. C-27 � High end osc. C-43, C-66 � 1st & 2nd R-F L-10, L-20, L-30 Ant. & 1st and 2nd R-F. 5 5 Repeat 5 5 Repeat 28 and 200 ohms 200 ohms frequencies are as indicated. 200 ohms � Max. output 200 ohms � Untouched remain in alignment over the ban *31 � 6 � 19,100 32 � 6 � 30,400 33 � Repeat 31 and 32 until end 34 � 6 � 30,000 35 � 6 � 19,500 36 � Repeat 34 and 35 until circuits *NOTE: On all coils, except Nos. 5 and 6 band oscillator coils (L-55, and L-56) turning the core clockwise increases the induct- ance. On the above two mentioned coils, turning the core clockwise de- creases the inductance. C-45, C-68 � 1st & 2nd R-F L-12, L-21, L-31 Ant. & 1st and d. � 2nd R-F. On all bands the oscillator tracks above the sig nal frequency. If more than one peak is obtainable on oscillator use the higher frequency peak. L-56 � Low end osc. C-32 � High end osc.

be made such as replacement of the range switch, it is necessary first to remove the complete R-F unit from the receiver. To do this the following procedure should be observed: (a) Remove the chassis and panel from the cabinet by removing the four panel mounting screws and sliding the chassis forward out of the cabinet. (b) Remove the knobs by means of the small wrench held in the spring clip on the right hand side of the chassis. This wrench fits the set screws in all knobs except the main tuning knob. For this knob use an ordinary small screw driver. (c) Remove the panel by removing the eight nuts with which it is held to the support brackets. (d) Remove the large cover from the top of the R-F unit, by removing the four knurled nuts with which it is sup- ported. (e) Remove the small cover from the tun- ing condenser, by removing the eight knurled nuts with which it is supported. (f) Remove the dial light sockets where they are clipped on to the tuning unit. (g) Remove the antenna trimmer shaft extension by loosening set screw in coupling with same wrench as used above for knobs. (h) Remove support bracket from fly- wheel tuning shaft. (i) Remove main dial, vernier dial, and flywheel by loosening set screws with same wrench as used for knobs. (j) Disconnect the eight leads which con- nect the R-F unit to the main base. These leads are as follows:— (i) Two on the antenna terminal board (blue and black). (ii) One on number 7 pin of the 6V6GT/G output valve (brown). (iii) One on terminal E of the crystal load circuit (yellow). (iv) One on terminal E of the first I-F Transformer (red). (v) One on terminal F of the first I-F Transformer (blue). (vi) One on pin 6 of the second I-F valve (green). (vii) One on pin 7 of the second I-F valve (brown). In addition, the by-pass condenser which grounds to the R-F unit near the second I-F valve must be dis- connected. (k) Remove eleven screws which hold R-F unit to main base. Three of these are on under side of chassis along the front edge. The other eight are re- moved from the top. (I) The R-F unit may now be removed from the bottom by lifting up first the rear of the R-F unit and sliding it hack out of the opening. After the unit has been repaired it may he re- assembled by following the above procedure in reverse order. [14)

MI-22215 (6-Volt Storage-Battery Operation) (Note: This item supplied only when specifically ordered) 7.1 General 7.1-1 The MI.22215 identifies the equipment fur- nished with the power supply unit and consists of the following items: 1—Vibrator Power Supply, complete with vibrator and Type-OZ4A rectifier valve. 1--Power • Cable, approximately 8 feet long, equipped with power switch, fuse holder and fuse, terminals for connect- ing to the vibrator power supply unit, and terminating in a plug for connect- ing to the associated receiver. 7.1-2 Electrical Characteristics:— Output . 300 volts, 90 ma. Battery Voltage ... ... 6 to 8 volts Total current drain (operating AR-88-LF.) receiver 12 amperes Fuse Rating � 20 amperes 7.1-3 Valve Complement � 1 Type OZ4A 7.1-4 Mechanical Specifications:— Dimensions:— Height . � . � ... 61/2 inches Width �5 inches Depth � 51/a inches Weight (net) .. . � . 7 pounds 7.2 Technical Details: � The MI.22215 vibrator power supply unit is primarily designed for the purpose of adapting the General Purpose Com- munication Receiver (Model AR-88LF) to 6-volt battery operation. Four rubber feet are provided for resting the unit on a table or shelf. If pre- ferred, these feet may be removed to expose threaded studs by which the unit may be bolted permanently in position. NOTE--The power supply unit must be mount- ed with the vibrator in an approximately ver- tical position. Direct current at high potential is obtained by means of a non-synchronous vibrator used in conjunction with a step-up transformer. Rectifi- cation is obtained by the use of a Type OZ4A rectifier valve. This power unit has been de- signed and tested to operate under a wide variety of climatic conditions. 7.3 Installation 7.3-1 Connecting the power cable to the vibrator power supply unit. In order to connect the power cable to the vibrator power supply unit, first remove the terminal board cover from the power unit by removing the two self-tapping screws in the cover. About four feet from the end of the cable to which the two large battery clips are at- tached, a group of four wires, each about four inches long and equipped with a spade terminal, extends from the cable. These leads should be connected to the power unit terminal board — the brown lead to the terminal marked "A—HOT", the yellow lead to "B—" and the red lead to "B+." Replace the terminal board cover with the three leads extending from the open end of the cover, connecting the black lead under one of the screws which hold the cover. 7.3-2 Mounting the Switch. Fasten the switch to bracket on the top of the transformer can, or to any place convenient to the Power Supply. 7.3-3 Connecting the Power Cable to the Re- ceiver. Remove the plug from the socket on the rear apron of the receiver. Insert the plug, on the end of the vibrator power supply cable, into this socket. 7.3-4 Adjustments. A four-position rotary switch on the rear of the chassis is used to adjust the vibrator output voltage to compensate for variations in the battery voltage. The positions on this switch are numbered from "1" to "4" inclusive. The position in which the switch rotor is placed is indicated by the direction in which the screw-driver slot in the rotor shaft is pointing. For pro- per selection of the switch position, consult the following table: Switch Position � 'A' Battery Voltage 4 � 6.0 to 6.5 Volts 3 � 6.5 to 7.0 Volts 2 � 7.0 to 7.5 Volts 1 � 7.5 to 8.5 Volts 7.3-5 Connecting the Power Cable to the Storage Battery. Turn the power switch in the power cable to the "OFF" position. These are two battery clips connected to one end of the power cable, each clip serv- ing to terminate a pair of wires. On one clip, both wires are black while on the other clip one wire is green and the second is brown. Connect the clip with the two black wires securely to the negative (—) terminal of the storage battery. Be sure to make good contact at this point. Connect the clip with the green and brown wires

C-S ./ �SOO /47FOT �MMF "8" # 47A" chltm-e- (=> , C-7 2S"4-DT P/ 0 RE-0 Bt/ ---‘' YELLOW 87. ,- @ ®47L X' Ce A- Li * , ®gee-ew A* ,S1s)/ O Cia-/ C.4.9ch- S//c2/ 1/4/ � COL/A/7-ER CLOCA-W/SE / ROSY 7/0/1/ AND WEIVE0 FROM .17e04/7 OF - (N48S/S. securely to the positive (+) terminal of the battery. The receiver is now ready for operation from the power supply unit. NOTE: Since the power line cord supplied with the receiver is completely out of the circuit when the vibra- tor power supply is used, this cord should be wound up and placed inside of the receiver case in the space between the chassis and the case wall. 7.4 Operation:— The switch on the power cable must be used for turning the receiver on and off, the power switch on the receiver being automa- tically cut out of the circuit when the vibrator power supply unit is used. To prevent impair- ment of normal operation, the following pre- cautionary measures should be observed: (a) Never remove the rectifier valve while the power supply unit is in operation. Serious damage to circuit elements, or even to the vibrator itself, may result under these conditions. (b) Never disconnect any leads on the power cable unless the power switch is turned off. Never tighten any terminal screws unless the power is definitely off. Should it become necessary to tighten any or all of the screws on the vibrator power unit terminal board, always first remove the battery clips from the battery. THIS is extremely important, since failure to follow this rule will invari- ably result in serious damage to the vibrator power unit itself. 7.5 Maintenance: � A schematic diagram of the vi- brator power supply unit is shown in Figure 5. The diagram symbol of each part is repeated in the parts list to facilitate identification by means of cross reference. Service generally consists of replacing the vibrator which may have deterio- rated through prolonged usage. If excessive out- put hum should occur during operation, the cause may be a filter-circuit breakdown, such as leaky or short-circuit filter capacitors. When servicing the power supply unit, disconnect it from its source of voltage supply and, using an ohmmeter, check through for continuity. Capacitors should be tested by first removing one side from the adjacent connections so that the capacitor under test is not connected in the cir- cuit. The power supply unit is protected by a 20- ampere fuse which in the event of failure should be replaced by one of identical rating. Figure 5.-1-ibratur Power Supply -- MI-22215 — Schematic Diagram. [16]

PARTS LIST GENERAL PURPOSE COMMUNICATION RECEIVER Schematic Reference Nomen- clature DESCRIPTION RCA Victor Mfg. No. r. of a Spaval Spares R.C.A.F. Ref. No. A-1 Crystal 735 KC Crystal & Case � MI-19454-2 1 10X/735 C-1 Condenser 4700 mmfd. ± 10%, 500V, (mica) � 102899-507 3 10C/8102 C-2 Condenser 3-25 mmfd., 5 Plate Antenna Trimmer � 253132-2 1 10C/8121 C-3 Condenser 10-410 mmfd. � C-4 Condenser 220 mmfd. ± 10%, 500V, Temp. Coeff. - .00075 mmf./mmf./°C 90581-341 2 10C/8086 C-5 Condenser Same as C-4 � *C-6 Condenser 8-88 mmfd. � C-9 Condenser 10 mmfd. ± 10%. 500V, Temp. Coeff. - .00075 mmf./mmf./°C 90581-309 1 10C/8087 C-11 Condenser Same as C-1 � C-12 Condenser 56 mmfd. ± 10%, 500V, Temp. Coeff. - .00075 mmf./mmf./°C (inc. in L-57) � 90581-327 C-13 Condenser Same as C-4 � C-14 Condenser Same as C-4 � C-15 Condenser 47 mmfd. ± 5%, 500V, Temp. Coeff. - .00015 mmf./mmf./°C 90577-225 1 10C/8093 C-16 Condenser Air trimmer 2-20 mmfd � 95534-502 2 10C/8118 C-17 Condenser 68 mmfd. ± 5%, 500V, (mica) � 720538-39 1 10C/8111 C-18 Condenser 39 mmfd. ± 5%, 500V, Temp. Coeff. - .00012 mmf./mmf./°C 90574-223 1 10C/8092 C-19 Condenser Air trimmer 2-12 mmfd � 95534-503 1 10C/8119 C-20 Condenser 240 mmfd. ± 5%, 500V, (mica) � 720538-32 1 10C/8105 C-21 Condenser 15 mmfd. ± 5%, 500V, Temp. Coeff. - .00047 mmf./mmf./°C 90580-213 1 10C/8094 C-22 Condenser Air Trimmer - Same as C-19 � C-23 Condenser 1000 mmfd. ± 5%, 375V, (mica) � 721133-4 1 10C/8114 C-24 Condenser 2500 mmfd. ± 5%, 500V, (mica) � 721133-24 1 10C/8116 C-25 Condenser Air Trimmer - Same as C-19 � C-26 Condenser Same as C-21 � C-27 Condenser Air Trimmer 2-25 mmfd � 95534-501 2 10C/8120 C-28 Condenser 3000 mmfd. ± 5%, 500V, (mica) � 721133-12 1 10C/8115 C-29 Condenser 30 mmfd. ± 5%, 500V, Temp. Coeff. - .00047 mmf./mmf./°C 90580-220 1 10C/8099 C-30 Condenser 3900 mmfd. ± 5%, 500V, (mica) � 720538-46 1 10C/8112 C-31 Condenser 39 mmfd. ± 5%, 500V, Temp. Coeff. - .00047 mmf./mmf./°C 90580-223 1 10C/8098 C-32 Condenser Air Trimmer - Same as C-27 � C-33 Condenser Same as C-1 � C-34 Condenser Same as C-4 � *C-35 Condenser 10-370 mmfd � C-36 Condenser 1500 mmfd. ± 20%, 600V, (mica) � 98041-1 1 10C/8100 C-37 Condenser Air Trimmer - Same as C-16 � C-38 Condenser Air Trimmer - Same as C-16 � C-39 Condenser Air Trimmer - Same as C-16 � *C-40 Condenser 8-128 mmfd. C-41 Condenser Air Trimmer - Same as C-16 � C-43 Condenser Air Trimmer - Same as C-27 � C-44 Condenser 6.8 mmfd. ± 10%, 500V, Temp. Coeff. - .00075 mmf./mmf./°C 90581-305 1 10C/8088 C-45 Condenser Air Trimmer - Same as C-27 � C-46 Condenser Same as C-21 C-47 Condenser Same as C-1 � C-48 Condenser .05 mfd., 400V, (oil filled) (C-48, C-109, C-110, in one assembly) 98034-1 10C/8083 *C-49 Condenser 8-128 mmfd � *C-50 Condenser 10-370 mmfd. � C-51 Condenser Same as C-1 � C-52 Condenser Same as C-1 � C-53 Condenser Same as C-44 � C-54 Condenser Same as C-1 � C-55 Condenser 390 mmfd. ± 5%, 500V, (mica) (included in T-3) � 86079-505 C-56 Condenser .01 mfd., 400V, (oil filled) (C-56, C-76, C-93, in one assembly) � 98034-4 1 10C/8084 C-57 Condenser Same as C-4 � C-58 Condenser Same as C-36 � C-59 Condenser Air Trimmer - Same as C-16 � C-60 Condenser Air Trimmer - Same as C-16 � C-61 Condenser Same as C-9 � C-62 Condenser Air Trimmer - Same as C-16 � C-63 Condenser Same as C-1 � C-64 Condenser Air Trimmer - Same as C-16 � C-66 Condenser Air Trimmer - Same as C-27 � C-67 Condenser 22 mmfd. ± 10%, 500V, Temp. Coeff. - .00075 mmf./mmf./°C 90581-317 1 10C/8090 C-68 Condenser Air Trimmer - Same as C-27 � C-69 Condenser Same as C-46 � *C-70 Condenser 8-128 mmfd � C-71 Condenser � 0.1 mfd., 400V, (oil filled) � (C-71, C-95, C-102, in one assembly) 98034-2 1 10C/8085 C-72 Condenser � Same as C-55 (included in T-3) � C-73 Condenser � 100 mmfd. ± 5%, 500V, (included in T-4) (mica) � 86034-522 C-75 Condenser 3-15 mmfd. Crystal Phasing Trimmer � . 253132-6 1 10C/8123 C-76 Condenser .01 mfd., 400V, (see C-56) � [17)

Schematic Reference Nomen- DESCRIPTION clature RCA Victor Mfg. No. Qty. of Naval Spares R.C.A.F. Ref. No. *C-77 Condenser � 10-370 mmfd � C-78 Condenser Same as C-55 (included in T-5) � C-79 Condenser 0.1 mfd., 400V, (oil filled) (C-79, C-84, C-92, in one assembly) 98034-2 10C/8085 C-80 Condenser Air Trimmer - Same as C-16 � C-81 Condenser Air Trimmer - Same as C-16 � C-82 Condenser 56 mmfd. ± 5%, 500V, (mica) (included in T-10) 86034-517 C-83 Condenser Same as C-1 � C-84 Condenser 0.1 mfd., 400V, (See C-79) � C-85 Condenser 330 mmfd. ± 20%, 500V, (mica) (included in T-10) � 86034-524 C-86 Condenser 3-15 mmfd. B.F.Osc. Panel Trimmer � 253132-7 1 10C/8124 C-87 Condenser 1500 mmfd. ± 10%, 500V, (mica) (included in T-10) � 86034-548 C-88 Condenser Same as C-82 (included in T-10) � C-89 Condenser Same as C-55 (included in T-5) � C-90 Condenser Same as C-55 (included in T-6) � C-91 Condenser Same as C-55 (included in T-6) � C-92 Condenser 0.1 mfd., 400V, (See C-79) � C-93 Condenser 0.1 mfd., 400V, (See C-56) � C-94 Condenser Same as C-55 (included in T-7) � C-95 Condenser 0.1 mfd., 400V, (See C-71) � C-96 Condenser 4 mfd., + 20% - 10%, Dry Electrolytic (C-96,C-97,C-98 in one assembly) � 72026-515 1 10C/8081 C-97 Condenser 4 mfd., � 20% - 10%, Dry Electrolytic (See C-96) � C-98 Condenser 4 mfd., � 20% - 10%, Dry Electrolytic (See C-96) � C-99 Condenser .25 mfd., 400V, (oil filled) (C-99, C-112, C-113, in one assembly) � 98034-3 1 10C/8082 C-100 Condenser Same as C-55 (included in T-7) � C-101 Condenser Same as C-55 (included in T-8) � C-102 Condenser 0.1 mfd., 400V, (See C-71) � C-103 Condenser .05 mfd., 400V, (oil filled) (C-103, C-106, C-107, in one assembly 98034-1 1 10C/8083 C-104 Condenser Same as C-55 (included in T-8) � C-105 Condenser 560 mmfd. ± 10%, 500V, (mica) � 100404-528 1 10C/8101 C-106 Condenser .05 mfd., 400V, (See C-103) � C-107 Condenser .05 mfd., 400V, (See C-103) � C-108 Condenser Same as C-73 (included in T-9) � C-109 Condenser .05 mfd., 400V, (See C-48) � C-110 Condenser .05 mfd., 400V, (See C-48) � C-111 Condenser 2700 mmfd. ±.10%, 500V, (mica) � 102899-508 1 10C/8103 C-112 Condenser .25 mfd., 400V, (See C-99) � C-113 Condenser .25 mfd., 400V, (See C-99) � C-114 Condenser Same as C-73 (included in T-9) � C-115 Condenser 180 mmfd. ± 5%, 500V, (mica) (included in T-9) � 86034-513 C-116 Condenser Same as C-111 � C-117 Condenser Same as C-1 � C-118 Condenser Same as C-i � C-119 Condenser .003 mfd. ± 10%, 1000V, (oil filled) � 251248-3 1 10C/8117 C-121 Condenser Same as C-1 � C-122 Condenser Same as C-1 � C-123 Condenser Same as C-4. � C-124 Condenser 150 mmfd. ± 10%, 500V, Temp. Coeff. - .00075 mmf./mmf./°C 90581-337 1 10C/8091 C-125 Condenser 650 mmfd. ± 10%, 300V, (mica) � 720592-13 1 10C/8113 C-126 Condenser Same as C-125 � C-127 Condenser Same as C-20 � C-128 Condenser 285 mmfd. ± 5%, 500V, (mica) � 720538-31 1 10C/8104 C-129 Condenser � Same as C-9 � C-130 Condenser � Same as C-105 � NOTE: C-3, C-6, C-35, C-40, C-44, C-50, C-70, C-77, all parts of Variable Condenser Assembly 92444-502 10C/8122 F-1 Fuse 1.5 amp. 3 A G. in AC Line � 55544-2 8 5C/1705 ."1-1 Socket Connections for battery operations � 421395-509 2 10H/8168 :1-2 Jack Jack, phone � 98965-3 10H/8185 L-1 Coil Antenna Prim. 73-205 KC (L-1 & L-2 on same coil form) � 253674-506 10C/8142 L-2 Coil Antenna Sec. 73-205 KC (See L-1) � L-3 Coil Antenna Prim. 195-550 KC (L-3 & L-4 on same coil form) � 253674-507 10C/8143 L-4 Coil Antenna Sec. 195-550 KC (See L-3) � L-5 Coil Antenna Prim. 1480-4400 KC (L-5 & L-6 on same coil form) 95521-501 10C/8144 L-6 Coil Antenna Sec. 1480-4400 KC (See L-5) � L-7 Coil Antenna Prim. 4250-12150 KC (L-7 & L-8 on same coil form) � 95521-502 10C/8145 L-8 Coil Antenna Sec. 4250-12150 KC (See L-7) � L-9 Coil Antenna Prim. 11900-19500 KC (L-9 & L-10 on same coil form) 95521-503 10C/8146 L-10 Coil Antenna Sec. 11900-19500 KC (See L-9) � L-11 Coil Antenna Prim. 19000-30500 KC (L-11 & L-12 on same coil form) 253671-505 10C/8147 L-12 Coil Antenna Sec. 19000-30500 KC (See L-11) � L-13 Coil 1st R.F. Prim. 73-205 KC (L-13 & L-14 on same coil form) 253674-501 10C/8148 L-14 Coil 1st R.F. Sec. 73-205 KC (See L-13) � L-15 Coil 1st R.F. Prim. 195-550 KC (L-15 & L-16 on same coil form) � 253674-502 10C/8149 L-16 Coil 1st R.F. Sec. 195-550 KC (See L-15) � [18)

Schematic Reference Nomen- clature DESCRIPTION RCA Victor Mfg. No. Qty. of aval Spares Pares Ref. Ref. No. L-17 Coil 1st R.F. Prim. 4250-12150 KC (L-17 & L-18 on same coil form) 253674-508 10C/8150 L-18 Coil 1st R.F. Sec. 4250-12150 KC (See L-17) � L-19 Coil 1st R.F. Sec. 1480-4480 KC (L-19 & L-61 on same coil form) 95520-503 10C/8151 L-20 Coil 1st R.F. Coil 11900-19500 KC � 253671-501 10C/8152 L-21 Coil 1st R.F. Coil 19000-30500 KC � 253671-502 10C/8153 L-22 Coil B.F. Osc. Coil (See T-10) � L-23 Coil 2nd R.F. Prim. 73-205 KC (L-23 & L-24 on same coil form) 253674-501 100/8148 L-24 Coil 2nd R.F. Sec. 73-205 KC (See L-23) � L-25 Coil 2nd R.F. Prim. 195-550 KC (L-25 & L-26 on same coil form) 253674-502 10C/8149 L-26 Coil 2nd R.F. Sec. 195-550 KC (See L-25) � L-27 Coil 2nd R.F. Prim. 4250-12150 KC (L-27 & L-28 on same coil form) 253674-508 10C/8150 L-28 Coil 2nd R.F. Sec. 4250-12150 KC (See L-27) � L-29 Coil 2nd R.F. Sec. 1480-4400 KC (L-28 & L-60 on same coil form) 95520-503 10C/8151 L-30 Coil 2nd R.F. Coil 11900-19500 KC � 253671-501 10C/8152 L-31 Coil 2nd R.F. Coil 19000-30500 KC � 253671-502 10C/8153 L-32 Coil I.F. Trans. Prim. (See T-3) � L-33 Coil I.F. Trans. Sec. (See T-3) � L-34 Coil Crystal Selectivity Coil (See T-4) � L-35 Coil I.F. Trans. Prim. (See T-5) � L-36 Coil I.F. Trans. Sec. � (See T-5) � L-37 Coil I.F. Trans. Prim. (See T-6) � L-38 Coil I.F. Trans. Sec. � (See T-6) � L-39 Coil Variable Selectivity Coil (See T-5) � L-40 Coil Variable Selectivity Coil (See T-6) � L-41 Coil I.F. Trans. Prim. (See T-7) � L-42 Coil I.F. Trans. Sec. � (See T-7) � L-43 Coil I.F. Trans. Prim. (See T-8) � L-44 Coil I.F. Trans. Sec. � (See T-8) � L-45 Coil Variable Selectivity Coil (See T-7) � L-46 Coil Variable Selectivity Coil (See T-8) � L-47 Coil I.F. Trans. Prim. (See T-9) � L-48 Coil I.F. Trans. Sec. � (See T-9) � L-49 Coil Filter Choke � 901433-501 1 10C/8154 L-50 Coil Filter Choke — Same as L-49 � L-51 Coil Oscillator 73-205 KC � 253674-503 10C/8155 L-52 Coil Oscillator 195-550 KC � 253674-504 10C/8156 L-53 Coil Oscillator 1480-4400 KC � 95520-506 10C/8157 L-54 Coil Oscillator 4250-12150 KC � 253674-505 10C/8158 L-55 Coil Oscillator 11900-19500 KC � 253671-503 10C/8159 L-56 Coil Oscillator 19000-30500 KC � 253671-504 10C/8160 L-57 Coil I.F. Wave Trap (includes C-12) � 253481-502 1 10C/8161 L-60 Coil 2nd R.F. Prim. 1480-4400 KC (See L-29) � L-61 Coil 1st R.F. Prim. 1480-4400 KC (See L-19) � P-1 Plug AC Power Plug & Cord � 811638-1 P-2 Plug in J-1 for normal AC operation. � 99895-501 1 1011/8184 R-1 Resistor 33,000 ohms ± 10% 1/2 W � 850981-80 1 10C/8134 R-2 Resistor 2.2 meg. ± 20% 1/2 W. � 850981-33 1 10C/8131 R-3. Resistor 1,000 ohms ± 10% 1/2 W. � 82283-62 2 10C/1673 R-4 Resistor 100,000 ohms ± 10% 1/2 W. � 82283-86 1 10C/3281 R-5 Resistor 1.0 meg. ± 20% 1/2 W � 82283-31 1 10C/5750 R-6 Resistor Same as R-1 � R-7 Resistor 330 ohms ± 10% 1/2 W � 82283-56 1 10C/7729 R-9 Resistor Same as R-4 � R-10 Resistor Same as R-3 � R-11 Resistor 10,000 ohms ± 10% 1/2 W � 82283-74 1 100/1675 R-12 Resistor Same as R-3 � R-13 Resistor 560 ohms ± 10% 1/2 W. � 850981-59 1 10C/7259 R-14 Resistor Same as R-4 � R-15 Resistor 22,000 ohms ± 10% 1/2 W. (included in T-3) � 82283-78 R-16 Resistor Same as R-3. � R-17 Resistor Same as R-7 � R-19 Resistor Same as R-1 � R-20 Resistor 100 ohms ± 10% 1/2 W. � 82283-50 1 10C/3260 R-22 Resistor Same as R-3 � R-23 Resistor 560,000 ohms ± 10% 1)/2 W. 82283-95 2 10C/6688 R-24 Resistor � 120,000 ohms --- 10% 1/2 W. (included in T-10) 82283-87 R-25 Resistor � 47 ohms ± 10% 1/2 W. � 82283-46 1 10C/7747 R-26 Resistor Same as R-3 � R-27 Resistor Same as R-23 � R-28 Resistor � Same as R-24 (included in T-10) � R-29 Resistor � ' � 47,000 ohms ± 10% 1/2 W. (included in T-10) � 82283-82 R-30 Resistor � 2,700 ohms ± 10% 4 W. � 90497-3 1 10C/8128 R-31 � Resistor � Same as R-3. � R-32 � Resistor � ' 390 ohms ± 10% 1/2 W. � 850981-57 1 10C/7282 [193

Schematic Reference Nomen- clature DESCRIPTION RCA Victor Mfg. No. Wrt Va Spares R.C.A.F. Ref. No. R-33 Resistor Same as R-2 � R-34 Resistor Same as R-3 R-35 Resistor 680,000 ohms ± 10% 1/2 W. � 850981-96 1 10C/8137 R-36 Resistor Same as R-2 � R-37 Resistor 1.0 meg. ± 20% 1/2 W. � 850981-31 1 10C/1651 R-38 Resistor 1.5 meg. ± 10% 1/2 W � 850981-100 1 10C/1921 R-39 Resistor Same as R-20 � R-40 Resistor 270,000 ohms ± 10% 1/2 W. � 850981-91 1 10C/8136 R-41 Resistor 100,000 ohms ± 10% 1/2 W. � 850981-86 1 10C/8135 R-42 Resistor 390,000 ohms ± log 1/2 W. 82283-93 1 10C/8027 R-43 Resistor 100 ohms ± 10% 4 W. � 90497-1 1 10C/8127 R-44 Resistor 150 ohms ± 10% 4 W � 90497-6 1 10C/8129 R-45 Resistor 15 ohms ± 10% 1/2 W � 867970-340 1 10C/8138 R-46 Potentiometer 66,000 ohms R.F. Gain Control � 251402-2 1 10C/8139 R-47 Resistor Same as R-2 � R-48 Potentiometer Same as R-46 (Noise Limiter Control) � R-49 Resistor Same as R-1 � R-50 Resistor Same as R-23 � R-51 Potentiometer 2. meg. Audio Gain Control � 251402-3 1 10C/8140 R-52 Potentiometer 1 meg. Tone Control � 251402-1 1 10C/8141 R-53 Resistor 330,000 ohms ± 10% 1/2 W � 82283-92 1 10C/8126 R-54 Resistor 2,700 ohms ± 10% 1/2 W. � 850981-67 1 10C/8132 R-55 Resistor 6,800 ohms ± 10% 1/2 W. � 850981-72 1 10C/8133 R-56 Resistor 39 ohms ± 10% 4 W � 90497-7 1 10C/8130 R-58 Resistor 5,600 ohms ± 10% 1/2 W � 82283-71 1 10C/8125 R-60 Resistor Same as R-58. � R-61 Resistor Same as R-25 � R-62 Resistor Same as R-25 � R-63 Resistor Same as R-23 � R-64 Resistor Same as R-23 � R-65 Resistor Same as R-23 � R-66 Resistor Same as R-54. � R-67 Resistor Same as R-54 � S-1 Switch Range Sw. Wafer Oscillator Ccts. (S-1 & S-2 on same wafer) S-2 Switch Range Sw. Wafer Oscillator Ccts. (See S-1) � S-3 Switch Range Sw. Wafer Oscillator Ccts. (S-3 & S-4 on same wafer) � S-4 Switch Range Sw. Wafer Oscillator Ccts. (See S-3) � S-5 Switch Range Sw. Wafer 2nd R.F. Ccts. (S-5 & S-6 on same wafer) S-6 Switch Range Sw. Wafer 2nd R.F. Ccts. (See S-5) � S-7 Switch Range Sw. Wafer 2nd R.F. Ccts. (S-7 & S-8 on same wafer) S-8 Switch Range Sw. Wafer 2nd R.F. Ccts. (See S-7) � S-9 Switch Range Sw. Wafer 1st R.F. Ccts. (S-9 & 10 on same wafer) S-10 Switch Range Sw. Wafer 1st R.F. Ccts. (See S-9) � S-11 Switch Range Sw. Wafer 1st R.F. Ccts. (S-11 & 12 on same wafer).... S-12 Switch Range Sw. Wafer 1st R.F. Ccts. (See S-11) � S-13 Switch Range Sw. Wafer Antenna Ccts. (S-13 & S-14 on same wafer) S-14 Switch Range Sw. Wafer Antenna Ccts. (See S-13) � S-15 Switch Range Sw. Wafer Antenna Ccts. (S-15 & S-16 on same wafer) S-16 Switch Range Sw. Wafer Antenna Ccts. (See S-15) � NOTE: S-1 to S-16 included all on one assembly � 253660-1 10F/8167 S-17 Switch Crystal Sw. Wafer (S-17 & S-18 on same wafer) � S-18 Switch Crystal Sw. Wafer (See S-17) � S-19 Switch Crystal Sw. Wafer (S-19 & S-20 on same wafer) � S-20 Switch Crystal Sw. Wafer (See S-19) � NOTE: S-17-18-19-20 all on same assembly � 253134-1 10F/8165 S-21 Switch A.V.C. - N.L. Switch Wafer (S-21 & S-22 on same wafer) 253099-1 10F/8166 S-22 Switch A.V.C. - N.L. Switch Wafer (See S-21) � S-23 Switch Off-Trans.-B.F.O. Switch Wafer (includes S-24) � 253098-1 1 10F/8163 S-24 Switch On/Off Toggle Sw. (See S-23) � S-25 Switch D.P. D.T. Line voltage Switch � 252657-1 1 10F/8164 T-1 Transformer Power. 115/230 V. 25-60 cycle � 901602-501 1 10A/8173 T-2 Transformer Output. 2.5 ohms & 20 ohms � 901611-501 1 10A/8174 T-3 Transformer 1st I.F. (includes L-32, L-33, C-55, C-72, R-15) 735 KC � 255401-501 1 10A/8175 T-4 Transformer I.F. Crystal Load (includes L-34 & C-73) 735 KC � 255401-505 1 10A/8176 T-5 Transformer 2nd I.F. (Includes L-35, L-36, L-39, C-78, C-89) 735 KC � 255401-5031 T-6 Transformer 2nd I.F. (Includes L-37, L-38, L-40, C-90, C-91) 735 KC � 255401-503 T-7 Transformer 3rd I.F. (Includes L-41, L-42, L-45, C-94, C-100) 735 KC � 255401-503 1 10A/8177 T-8 Transformer 3rd I.F. (Includes L-43, L-44, L-45, C-101, C-104) 735 KC � 255401-503 T-9 Transformer 4th I.F. (Includes L-47, L-48, C-108, C-114, C-115) 735 KC � 255401-502 1 10A/8178 T-10 Transformer B.F. 0. (Inc. L-22, C-82, C-85, C-87, C-88, R-24, R-28, R-29) 735 KC 255401-504 1 10A/8179 TB-1 Term. Bd. Antenna & Ground. 3 term. � 253669-2 TB-2 Term. Bd. 5 Term � � 253669-1 TB-4 Term. Bd. Output for external spk. 2 term � 253669-3 V-1 Valve 1st � R.F. Amplifier 6SG7 [20]

6SG7 V-3 Valve Master Oscillator � 6J5 V-4 Valve 1st Detector, Converter � 6SA7 6 V-5 Valve 1st � I.F. Amplifier � 6SG7 V-6 Valve 2nd I.F. Amplifier � 6SG7 12 10E/8188 V-7 Valve 3rd I.F. Amplifier � 6SG7 V-8 V-9 Valve Valve 2nd Detector & A.V.C. � Noise Limiter. � 6H6 6H6 8 V-10 Valve 1st A.F. Amplifier � 6SJ7 6 V-11 Valve Output � 6V6GT/G 6 V-12 Valve B.F. Oscillator � 635 8 V-13 Valve Voltage Regulator � VR-150 6 10E/4298 V-14 Valve Rectifier � 5Y3GT/G 6 V-16 Valve Gas Gap Protector � 991 4 10E/6827 X-1 Socket Tube socket for V-1 � 421395-507 1 10H/8169 X-2 Socket Tube socket for V-2 � Same as X-1 � X-3 Socket Tube socket for V-3 � 421395-508 1 10H/8170 X-4 Socket Tube socket for V-4 � Same as X-3 � X-5 Socket Tube socket for V-5 � Same as J-1 � X-6 Socket Tube socket for V-6 � Same as J-1 � X-7 Socket Tube socket for V-7 � Same as X-1 � X-8 Socket Tube socket for V-8 � Same as X-1 � X-9 Socket Tube socket for V-9 � Same as X-3 � X-10 Socket Tube socket for V-10 Same as J-1 � X-11 Socket Tube socket for V-11 Same as X-1 � X-12 Socket Tube socket for V-12 � 421395-510 1 10H/8171 X-13 Socket Tube socket for V-13 Same as J-1 � X-14 Socket Tube socket for V-14 Same as J-1 � X-16 Socket Tube socket for V-16 � 837884-2 1 10H/8172 Board, Resistor � 98958-1 Board, Terminal assembly 2 Way � 81641-23 Board, Terminal assembly 1 Way � 81641-32 Board, Terminal assembly 1 Way vertical � 81641-57 Bracket assembly (for tuning shaft) � 99819-501 Coupling � 98950-1 Coupling � 99630-1 Caps — Shield Can. � 99840-1 Dial Assembly � 98947-503 10A/8187 Fuse Holder � 844027-2 5C/1304 Knob (Large) � 712336-503 10A/8180 MISCELLANEOUS Knob (Medium) � Knob (Small) � 712336-505 712336-507 10A/8181 10A/8182 Lamp — Pilot 1/4 Amp. 6V � 61114-15 12 5L/777 Screw — Knurled Thumb � 252664-1 Screw — Thumb � 99610-9 Screw — Set #8-32 for small knob � 844365-12 Screw — Set #8-32 for medium knob � � 844365-13 Screw — Set #10-32 for large knob � 59101-6 Socket Pilot Lamp (complete) � 98983-501 Tool — Air Trimmer Adj � 81059-501 10D/8189 Tool — I.F. Adj. � 86183-501 10D/8186 Tool — Set Screw Wrench � � 828505-12 Tuning Unit � 92417-1 TABLE Vernier Assembly � NUMBER VI — PARTS LIST — Vibrator Power Supply 98947-502 Unit (MI-22215) 10A/8183 C-1 Condenser 0.5 mfd., ± � 10%, 120 volts � 114125-5 C-2 Condenser .008 mfd., ± � 10%, 2000 volts � 114125-6 C-3 Condenser .05 mfd., ± 10%, 600 volts � 114125-7 C-4 Condenser 0.1 mfd., ± 10%, 600 volts � 114125-8 C-5 Condenser 500 mmfd., ± 10%, 600 volts (mica) � 114125-9 C-6 Condenser Electrolytic, 10 mfd., 450 volts. � 114125-10 C-7 Condenser Electrolytic, 25 mfd., 40 volts � 114125-11 C-8 Condenser Same as C-5 � CP-i Cable Power Cable, includes P-1, S-1 � 107617-501 F-1 Fuse Type 3 AG, 20 Amperes � 55544-10 L-1 Coil Filter Choke (iron core) � 98567-1 L-2 Coil Filter Choke � 114125-2 P-i Plug 8 prong octal plug (on CP-1) � 413691-8 R-1 Resistor 5,000 ohms, ± 10%, 1/4 Watt � 114125-4 S-1 Switch ON-OFF Switch, D.P.S.T. (on CP-1) � 845786-3 S-2 Switch Voltage Tap Switch—Water type � 114125-3 T-1 Transformer Vibrator Transformer � 114125-1 TB-1 Terminal Board Voltage Terminal Board, 3 term. � 114125-14 V-1 Valve Rectifier � OZ4A VS-1 Vibrator Dual Contact Vibrator � 110112-1 X-1 Socket Octal Socket for V-i 114125-13 X-2 Socket 6-Pin Socket for VS-1 114125-12 TABLE NUMBER V — PARTS LIST (Continued) [21]

General Purpose Communications Receiver—Rear View Figure 7.—General Purpose Communications Receiver � Top View [23)

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R.33 522 REAR ,5/ FRONT .5/6 eA-A.e R53 C/00 R40 C//8 w Ta R4/ R38 R44 R43 C/7 R37 R45 R3G ie 39 C/// R.50 C78 C84 C50 5P4ee ,voc acx- � ts �7-e/ � £F--cerri7 36, C76 / � C � C//9 � 5450 4taTO Co 8 WAVE 7R6v, e 23 C'75 C 8/ cRY-574L 5/9 F.eO/T sea RaeR y5 4 � c99 Cite 5C5 � / C//3 ,e 55 � 256, N C7/ C 95 ,e es � R 5/ � C//c, � R46 � G /2/ c/oa X 7 � R.3e � C/0.3C � C/0.5 C/0 7 Figure 9.—General Purpose Communications Receiver—Bottom View � Covers Removed. [271

S-43-1 5-/6 � Z 3 $9Z-/0 � cr` s-xe 7 � S � /-/./ Z-/2 C- 4 7 � Z-2 C-43 C-39 r � Y C- 3 6- x-r � z- 20 ,e-r � 7 C-6/ L-/71L-/8 6- 2 � C-37 L.-/-3-eZ-/6" � L-2/ C-/2S � C-116 C-3(9 � C- C-34 � Z- 30 z-e3 sei-e42 C-

6SG7 3.° I F. 6SG7 65A7 15TDET. 6SG7 6SG7 R31 6SG7 18TR.F. 1000 2"0R.F. 2., I F. IST I.F � ../\A � V7 01 0 &Id mope ::: � 7 04.112 C54 R13 V6 C71 0103 05 L4I L42 MFDT / � L43 T8 = L44 OIMF0.7. B RI9 33M 8 ©`W,'® 02 0 L35 1.36 � L37 L38 1 T5, c439 � T6/ I iletkIr 590 390)40','fir ;:0 L47 � L48 1 � T9 � I LW' -4-1 F1317.7, � g .i_ 041 � 100 c •-100 4 C � A ISO - a3eke' J1?7?9°.` ' T3 L32 jirp, � T4 jir.)_,„,. 4700 CI _1_ C52 4700 4 c94 90 a � c B RICT -11-4 j_ C107 I '4% 1133 I 0, 2 2MEG 05 MFD C55 L39 ROE 1000 C93 40 � MFD C95 I,VDT - 47 Cl,} 01 MFD 390 L45 46 A • 11 ) R34 1000 C75 ‘'IM'CI =0 3-15 R26 1000 R47 —1 C92 0.1MFO 0102 OIMFO C2 3-25 C3 H3-410 2 2 MEG C53 •� cztg R48 66M 68 R7 30 037 4 � 2.20 R. 6 7 3 C38 2-20 C I 2-20 :t 2-20 239 3 3 NOISE LIMITER 7 330 25 ▪ 9 242 20 R35 680M � R49 33M L1 � . � l2 4 0124 Jr 150'. /30700 3 061 I 3 47 2-2 C60 C70_ 4 � 9-ize C109 051400 L3 � L4 14 S20 REARAH_ (CRYSTAL Al FRONT 4 2 — FRONT CII0 05MFD I � L29 3 L6 4 064 2-20 L5 L79 jr L9 R27 560M C 023 L28 CS 2-20 61.16 NOISE LIMITER e V9 0 0 willp& *WC& � 18.2 CD 4 ▪ C66 2-2.0 2 � L30 1- 1-c67 T 22 � +002 8 LI R 50 560M LII IL12 C63 911 4700 FRONT [ 1000 C48 05 MFD C7 T 4700 100M Oa_ AVC-NOISE LIMITER SWITCH 2 , � B AN RANGE SWITCH SHOWN IN POSITION 1 (75 TO 200 KC) SELECTIVITY SWITCH (S17, 18,19, 2.0) SHOWN IN POSITION 1 (BROAD) AVC- NOISE LIMITER SWITCH (521, 522) SHOWN IN MANUAL POSITION WITHOUT NOISE LIMITER OFF - TRANSM -REC SWITCH (523, SEA) SHOWN IN "OFF" POSITION. CII6 RANGE SWITCH (51 TO 516 INCL. ) SHOWN IN MAX. COONTER/CW POSITION (BAND 1) AS VIEWED FROM FRONT OR KNOB END OF SWITCH. 2700 4 8 �0 5 7 6 ;AND � RANGE 1_73-203 KC 2___195- 550 KC 3_ _ _148-4 4 MC 4_ __425-1215MC 3___119-19 5 MC 6___190-305MC 522 REAR 521 FRONT II � CIII 1 2R1.15EG AUDIO GAIN 2 991 � OLOW TUSE 1131 C lr() :A 2700 CAPACITORS CI II, 33, 4Z 51, 52, 54, 63, 83, 118, 121, 122 MAY BE Cl MFD (P7.86091-511) EXCEPT THAT FOR 0118, 122 A SINGLE 01 MFD SHOULD BE USED. CII7 MAY BE 006 MFD (PT .86091-509) CIII, 116, 119 MAY BE 003 MFD (P7.86091- 507). 016 � L 6V6 GT/G OUTPUT 6J5 BEAT FREG OSC. VI2 6 5_7 7 is, A F R42 1136 2. 2MEG. 390M VIO TO TERM .4 VII 8 ON SOCKET 028 � R29 120M 0 47M ----AA-1 -'7W-1.7 . C84 ;!I65 T4C78050 I 272' L22 g92.?N1FD R97 I MEG 31 635 CI22 05C TO L gp, .'1; 5 � 4 -I- 4700 CIL5 330 C112 0 25 MFD.T CII7 � CHB 087 - 4700 4700 R52 1500 R24 - R40 270 M I MEG 013 120M 1153 330M 05-21"UT R54 2700 VR-I50 VOLTAGE REG. TIO A 220 R38 I SMEG CO _ � CONTROL C88 56 113 R39 � 023 100 � MFD \ � 1.5Z' -1 CI30 � I 560 8 R4I 100M 523 REAR 9 OFF-TRANS B F.0 SW C51 PHONE R56 JACK J2 4 14 � 44 VI3 0.30 seom seom 2700 2 � 524 (MOUNTED on S23) 1 J O I CKET TI Ij SOCKET (JI) C.ONNECTIONS FOR BATTERY OPERATION -"B" TO PIN * G 4'33' kw.7)-ro PIN .7 - 'A" TO PIN .5 + W(6V)TO PIN .4 5V L50 � L49 RECT 1170 525 V14 6,60 TB 2 TERMS 1 82 _ _ FOR EXTRA PAIR OF PHONES -}TRANSPI RELAY 5_ _ _ _DIVERSITY TB4 TERMS I a, a_ _EXTERNAL SPEAKER 2.54IMFEO BO 01 0 003 0 --C 97 4 MFD. C96 4MFD COO 4NFO 2340 V 117V4, R45 15 R43 R4, 100 � iso „• R46 R55 6800 66M TO ALL HEATERS (.11 0IRECT & DIAL LIGHTS R F GAIN NOTE - ALL CAPACITOR VAES YEN IN MAE ANO ALL RE515ToR SALUES GIVEN IN om LU MS tft & -ESS anrqw.sz SPEC FIED TUBE SOCI'.ETS ARE DESIGNATED BY 551180L V FOR GOKRESPONDiN0 TUBE N NUN BER NOTE.-USE PHONES WITH 600 OR LESS IMPED. Figure 11.—General Purpose Communications Receiver — Schematic Diagram.

.m=',==.1= ==::MMINOMOMIONIIME N.M,= ==.1111• . � ==%•M=1= 1•11•1•0111.••••IMMMMM=1:2 M.IIMMIMME � NEMER MMEIMM � == 2 .::: � Malt==111111.1.01=1•M MM MEINIIIIIMIJMNIMIIIMINUMWM.NHIM11.1.111f=l• � � • 1=1=1•1•= 'MEMNON � � IMA V_ NM se•mwmammris No me imam =muumuu prow � MI � 111.1110.1M.• � � 111•11M 1N IGIIIIIIINNIN MIEMMIMMAIIIIMIIII 1M MMEN11111: MIC111•111111111181111UMMM MMMMM � I � M• =mane 111111111NUM N il•MIII11/111 MMMMM IIIINIMIIIMIIIIIMIR111 MMMMMMMM MI � VIE MI MMMMM musrmerra 1111111N1111111MIMMERINIIIIIIIIIIMSUIll• � IMEMINI•••••11111111M•••11MANIMMENIIIIIIINNUMMININ111111 MMEMEMEME1111•11111111111••MMIIIIIMI � IIMEMINIIIIIIIN•IMMIBMIIIIIIIIIMM111111111111111•1W•IMIM k__,,-__=X-IOUMUNEMERUMMUVgPV===.- g :=.'2'"It Z 11===_ __=_Milffinila gallilla. 0: _=r__!-A 5- • � ff. - , • = - - - - - - = � ___==_'-a=1EqA, 8 11:7.=====AMMIESAIRAFri-OggagesjEig- EIREE .agE=2.7.-F. Ei-gy:M= � = � ====i-aMME=NriM � === ES= 6 C3 � 5 � Illniniir ilii*iii:;"'- � "- ==== 111112Malir.5 '."' � a a "I 5 4 � = � pmili WE-M.-7 .. E_I• 17.--7: -"j = lit � ---12,g-Eff== � =MINYININ•111=11•= 1=rair. :,..... � m••=. :-Sea Ii= i r=1 '..7am Imi7-, M=EM M=M.M ., .= •.==n M :: M Mmr Z M E .. I •. NS .M . . M=.. ..1. M•1••.4•= .! '=H 7MI.A = E . = , im � mm=mmnmmmm1 ontsmai = n emm Z : , ..,. � : .. 5 F. : •If, M 4 M ,.1 M 6.A M I. M I = == M=2 Kmn � mnommmmmaz nzrz2KA=.E.F..,.. � 2..===ac::::MMMMMM � I � a1l • =.7CC � 2.....,... l".1111,..I , � IIMMIN.M 4: NH ..i. •••••••••••••MOM �MO ill FP =11111141MMNIIIIIINIE � OTIIIIMP--./.. %,1441A4MMIllf 1 :1_,11111•Iiii•KN•F•MHIII .Lmoillimn..1111,61MBLEMEIBM.11111•E•M•1111111••I••••=11111115411M /0 � -,,-g,snagaummg..---- � --IUNNMMW=NINgi 7 6 5 4 8 2 / 0 000 I: Effallidill===k-saire-OffilakE_E=Ig . E-a.-ERMININTOMIIIIII 11111111111ININNIUMEZINEMINSINIF 18 ilitesMWEFR===giLgaggEIMIUMEINNIMAIS � NalffiNg gP-MIEB 9 BCMM ffMiW Minna= MON =111=111111/EMMEMINI MENIMEIMIN 11Z=1:==k4MBEIMIZM � -ESES7=E•M=== 7 IIIIIIIIIIM111111111111111111 � ELEEE.g.247.6 4 � minmengns � FRIMMIN ===_..L=,=====wriE_.= -:=mr....... - A MMMMM 2 � === j= MN ••••• � 2 moiEvigomommg � � I =ma IS WI �ME � MMMMM =MAUI/ pare imm msmsom 11M=I 1=ME/11 � MMEM11.111MUMMEME MEM. � M.ME 111 I kIMMII � WE INVE• ..111M. � .1E Ul 111111aMM Mill I ST •..1 4%1 111 ORIBMINA /00 0 � aME11111= SUMS mwmimminfilifillillaNZEWSP4t1 *21. = g RP_MINIERIM. MEM � tiliNEWERIII- E=. 52 I g � rang INgigg � I EE=E-_=.= � 6 7 4 � illi111111 IHMERIIIINEERIMENICEll 4 3 � =1111,:== aE 5M•ffif � == == � = 2EE-2 � 3 � =__-- == 8 i-li'a=-=== � - —= � .gEN,41nEininillEMM.g � —= MINEVENT BM == — s= � -=', E EigginidEMIENE- g _ =E::: = � _EE==Eg2BIERIMINSMIN 0 -=_ -== ==___-=- —='="iatWralarggilillMMNINgE -=grgg.nngMErr -- � .-- LIP-'WE � == — � .... � M=M11111MMISIERIU � m '2=RE...... 1•1= 12=1: � 2: AI M MITIVIraft= i 1 II gra � mmammommwammrmammem mim � MIMMAP1111111111101M MMMMMMM • HMINIIIIIL 111M • . 111. - � u..imulem....M III III 1111 lin IhM =MUM MEN NEM 1 i nia= NEM MINA NW.• /M1maMil1111Vm W=11111111 . PJ M. .1. Uli. WEE.. EINEM wounammino � ...WNW' 111.far _.. � MIME iW MEI= MEM /.17 SELECT/V/7Y CURVES AR-88 LF PO � /0 �0 �/0 � 20 / LO CYCZ ES. OFF PESO NA NCE Figure 12.—General Purpose Communications Receiver—Selectivity Characteristics. 33

. 11111111M11111 MI 11 11 61:11111111 111111_1 III WM RU 1111 1 ............. ............ HI IIMIIIIIIIIIM111111 IN hil.. .... 1 nil MI I 1111 +111111111111111111111 Ia. 1 nil Ill I MAIM I LINA OM OM ............... 01111111111MiLdWilir 'Pm imi_i_MENSIBI 1 irr Imp g Fikriar-f: aniumpuggip tegigulpiroodoilikai ktidi inn rurrilliMir"Iii • 1.,,, Pir ins • . • lir _ , 'Ill f _,.,iii,1-__ I 4 , 1 � ad , i , , I II I ill' Him " - d ii i i I i Mill nn Num „mil . � Ears Ii i „„„ Vindflial i Ii ii. ritiru „ii Miranda And= 11 „ „ limiffi i -- as „„ mom& MMINEHUlp 4FLORRIPMEMII ibillhboomomi 91110TPUMNIONIFORMINEME - � , ,,,,,; L , II i i-L RN i „ 1 1-0 1 .4 bllim.dmoduesdrimiammEN- I It : 11111 upwiromp phop,,HL rhmunol q Ell Mie wipmplopmqv :mai& 66 im Innor NEE - 1 i l'illikiliffill as it rrupor" I i IL ihirdi 1 AT m II " iinginagiinimm MAI NI INNI 1111111111_111r 1111111111111 hol An 111 ll id M NII " " M IMMUidgillilharkibilun mmuslummuligiumergur SIM • - -1_ - 1E1 I 11 I 1 i IA 7 Iourromon I a illilliIIIIIIIIN ..... r 1 1 - F � I � i l_i J . 1 1 iii_ T - 14 '4 ' lupprw r " hid 11 1- - , was is 1 „...mo..h ofir:Nrior 1 . I . UM IFF NERIng. libiald pqrdiNg gibalitilm ommoppron- iiiiddiriiiirE in — 11 ,siminshi... INtr , qg _ � _ , � 1 , ,,_,_ � , 1 =I- 2 „ 11, EMI mop v in 11111191111141061. 11111 rilIMPIE - lialinill y_ r1F- - _1_ _ 1 i L • t.111111111.1_ 1 I 1 1 14 i 1 -4j i r4 � -i 1 t � MI in 1 1 1 t � i 1111 11111111111RITI 1 lig implumumm EMU ,- - lilt Hill A - 101111 1 IIIIMMIll _ ... lit ..., II ,, _ 1- 1 o I- _ 1 , IL 1 1111 1 ILI" 1 � , - , - � 7- -I E MI milli - EN 11011111INEEN SIM= - PI -1 am iii 1 � 1 1111•111111111 1 MIMI , 1 I i U , P _ � _ i 1 H 1111 III 111 t 1 i 1 I ni Ill 1 di 1 � i - L � LT ' F 1, 1 - . MEM MI II i -i- 1 II i I I T 7- 1 1 ' I 1 11 1 1 1 1 1 1 MI 1 1 1 � 1 I I , , T-T- 1 � I 15 II fla i ' i fit � [ � : fit; � i Ho 1 � - r tl-g 71,vi, . � 1 1 4 1 � - - - 119 I ll ]4-0 , , .-1 r. T --FT- 1--- � i 1 � 4 1 � ' � . : i ' � LI III ' A I I, -,,i i 1 . i -T � , II- - - I i F i 1 , � -I. 1"-- CYCLES PER -SECOND CURVE /- SELECT/V/7Y .51,//TCH /N # / POS/T / 0 /V Caeve 2- SELECT/wry 51,NrcAl IN — e P05/r/ON THESE CURVES REFER TO BANDS 3 TO 6 ONLY THE RESPONSE ON THE HIGHER AUDIO FREQUEN- CIES ARE REDUCED ON BANDS I AND 2. Figure 13.—General Purpose Communications Receiver � Fidelity Characteristics. £34] .. O ' .8 /6 /.4 2 11) '.0 O 0.8 0.6 o.4 0.2

M/CR 0 VOLTS - INPUT Figure 1 4.—General Purpose Communications Receiver � Overload A.V.C. Characteristics. [351 /Os 0-/ /4 0.1 0 VCR LO A ND V. C A 8 8 - ve,2 � A ••••••••• A- v-e