Garland EM-C180US Manuals

CAUTION WARNING TO SERVICE TECHNICIANS PRECAUTIONS TO BE OBSERVED BEFORE AND DURING SERVICING TO AVOID POSSIBLE EXPOSURE TO EXCESSIVE MICROWAVE ENERGY (a) Do not operate or allow the oven to be operated with the door open. (b) Make the following safety checks on all ovens to be serviced before activating the magnetron or other microwave source, and make repairs as necessary: (1)Interlock operation, (2) proper door closing, (3) seal and sealing surfaces (arcing, wear, and other damage), (4) damage to or loosening of hinges and latches, (5) evidence of dropping or abuse. (c) Before turning on microwave power for any service test or inspection within the microwave generating compartments, check the magnetron, wave guide or transmission line, and cavity for proper alignment, integrity, and connections. (d) Any defective or misadjusted components in the interlock, monitor, door seal, and microwave generation and transmission systems shall be repaired, replaced, or adjusted by procedures described in this manual before the oven is released to the owner. (e)(i) A microwave leakage check to verify compliance with the Federal performance standard should be performed on each oven prior to release to the owner. (For U.S.A) (e)(ii) A microwave leakage check to verify compliance with the Canadian Regulation, HEALTH AND WELFARE, SOR/79-920 should be performed on each oven prior to release to the owner. (For CANADA) SERVICE MANUAL Microwave Oven EM-C180US PRODUCT CODE NO. 437-452-00 REFERENCE NO.SM-640179 CAUTION For microwave energy emission On every service call. A check for micro- wave energy emission must be made according to the following manner. Measurement of energy emission Measurement must be made with the microwave oven operating at its maximum output and containing a load of 275±15 milliliters of tap water initially at 20°±5° celsius (68±9°F) placed within the cavity at the center. NOTE:The water container must be a 600 milliliter bea- ker and made of an electrically none conduc- tive material such as glass or plastic. The cook tray must be in place when measuring emission. A properly operating door and seal assembly will nor- mally register emission no greater than 4 mW/cm2 to allow for measurement uncertainty with the cooking shelf or tray in place. All repairs must be performed in such a manner that microwave energy emission is minimal. Follow the instructions supplied with the detector be- ing used and perform an R.F. emission test around the door front, and all edges and vent of the outer case. The cabinet (wrapper) must be in place and the oven fully assembled. When performing an emission survey, with the meter on FAST RESPONSE, the movement of the detector probe shall not exceed one (1) inch per second. In the area emitting the highest reading, switch the meter to SLOW RESPONSE and take a reading for minimum of three (3) seconds. We recommended the pattern outline shown below when the door surface is surveyed. NOTE: Periodically check to be sure that the probe tip is not worn or dirty. The following U.S. standard applies to microwave ov- ens: 21 CFR 1030.10, Performance Standard for Microwave Ovens. It requires that the power density of the microwave radiation emitted by a microwave oven shall not ex- ceed five (5) milliwatts per square centimeter at any point 5 centimeters (about 2 inches) or more from the external surface of the oven. All microwave ovens exceeding the emission level of 4 mW/cm2 must be reported to Dept. of Service for mi- crowave ovens and the manufacturer immediately. The owner should be told not to use the microwave oven until it has been repaired completely. If a microwave oven is found to operate with the door open, report to Dept. of Service, the manufacturer and CDRH* immediately. Also tell the owner not to use the oven. *CDRH: Center for Device and Radiological Health. The interlock monitor switch acts as the final safety switch protecting the customer from microwave radia- tion. If the interlock monitor switch operates properly and the door interlock switch fails, the fuse will blow. If this happens, all interlock switches must be replaced. The contacts of the interlock switches may be welded together. - 3 - - TABLE OF CONTENTS - Adjustment Procedures............................................. 1 Specifications............................................................ 2 Power output Measurement ...................................... 2 Precautions and Repair Service Tips ....................... 2 Circuit Diagram ......................................................... 3 Test Procedures and Troubleshooting...............4 •`10 Disassembly Instructions .............................. 11 •`14 Exploded View and Parts List ........................ 15 •`22 Overall Circuit Diagram.................................23 •`25 1. ADJUSTMENT PROCEDURES TO AVOID POSSIBLE EXPOSURE TO MICROWAVE ENERGY LEAKAGE, THE FOLLOWING ADJUST- MENTS OF THE INTERLOCK SWITCHES SHOULD BE MADE ONLY BY AUTHORIZED SERVICE PER- SONNEL. The service center should have the designated detector to measure the microwave energy leakage after the repair or adjustment. NOTE: Detector to be used at the service center is NARDA 8100, 8200 or the equivalent. INTERLOCK SWITCH, INTERLOCK MONITOR SWITCH AND DOOR SENSING SWITCH ADJUST- MENT (Figure 1) (1) Loosen 2 screws securing the lever stopper. (2) Adjust the lever stopper position so that it is pushed up and pulled backwards until there is zero gap between the latch lever and the switch body on the interlock switch. At the same time there is zero gap between the latch lever and the switch body on the door sensing switch when the door latch is securely locked. (3) Tighten the lever stopper screws securely. (4) Make sure the interlock monitor switch closes after the interlock switch opens when the door is opened very slowly, according to “CHECKOUT PROCEDURE FOR SWITCHES” on page 6. (5) Make sure the interlock monitor switch opens before the interlock switch closes when the door is closed very slowly, according to CHECKOUT PRO- CEDURE FOR SWITCHES” on page 6. (6)(i) Make sure the microwave energy leakage should be no greater than 4 mW/cm2 to allow to measure- ment uncertainty when measured with a detector. (All service adjustments must be made for mini- mum microwave energy leakage readings.) (For US) (6)(ii) Make sure the microwave energy leakage is below the limit of 1 mW/cm2 (at 275cc water load), 5 mW/cm2 (at no load) and 5 mW/cm2 (at 275 cc water load without cabinet) when measured with a detector. (All service adjustments must be made for minimum microwave energy leakage readings.) (For Canada) NOTE: If the interlock monitor circuit operates and at the same time the fuse blows with the door open, be sure to replace the relay circuit board , Interlock switch and monitor switch. Interlock monitor switch Lever stopper Latch Lever Interlock switch (Secondary interlock switch) Latch Lever Door sensing switch (Primary interlock switch) Figure 1 Screws - 2 - 2.SPECIFICATIONS Microwave output ................ 1,800W to 180W Frequency ........................... 2,450MHz Power supply .......................208V, 60Hz Rated current ...................... 13 Amp. Safety Device ...................... Thermal protector(Magnetron) 150°C(270°F)Open (Thermostat) 80°C(144°F)Close Thermistor (Magnetron) 200°C(360°F) Open 108°C(194°F)Close Thermistor(Duct)................120°C(216°F) Open Fuse (Cartridge Type) ................. 250V 10A Micro switch, Relay Interlock Switch Interlock monitor Switch Door sensing Switch and Relay RL-3 and 4 Max. input time ....................Electronic Digital, up to Manual 10min./Memory 30min. Overall Dimensions........422(W)x540(D)x335(H) mm Oven cavity size ............330(W)x330(D)x230(H) mm Effective Capacity of Oven Cavity.........19.1liters Net weight ...........................32Kg 3. POWER OUTPUT MEASUREMENT A. SINCE NEARLY 4,000 VOLTS EXISTS IN SOME CIRCUITS OF THIS MICROWAVE OVEN, RE- PAIRS SHOULD BE CARRIED OUT WITH GREAT CARE. B. TO AVOID POSSIBLE EXPOSURE TO MICRO- WAVE ENERGY LEAKAGE, THE FOLLOWING PRECATIONS MUST BE TAKEN BEFORE SER- VICING. (1) Before the power is applied. (a) Open and close door several times to make sure the interlock switch, door sensing switch and interlock monitor switch operate properly. (Listen for the clicking sound from switches.) Make sure the interlock monitor switch is closed after the interlock switch and door sens- ing are open when the door is opened. (See pages 1 and 6) (b) Make sure the perforated screen and the choke dielectric of the door are correctly mounted. (2) After the power is applied. (a) Open and close the door to see if the interlock mechanism operates properly. (b) Check microwave energy leakage with a leak- age detector and confirm the energy leakage is below 5mW/cm2 (3) Do not operate the unit until it is completely repaired of any of the following conditions. (a) Door is not closed firmly against the cavity front. (b) The hinge is broken. (c) The choke dielectric or the door seal is dam- aged. (d) The door is bent or warped, or there is any other visible damage to the oven that may cause microwave energy leakage. Note: Always keep the seal clean. (e) Make sure that there are no defective parts in the interlock mechanism. (f) Make sure that there are no defective parts in the microwave generating and transmission assembly. (especially wave guide). (4) The following items should be checked after the unit is repaired. (a) The interlock monitor switch is connected cor- rectly and firmly. (b) The magnetron gasket on the magnetron is properly positioned. (c) Waveguide and oven cavity are intact. (No leakage of microwave energy). (d) The door can be properly closed and the safety switches work properly. (e) The oven must be stopped when the door is opened or the time is up. The oven must not be operated with any of the above components removed or bypassed. NOTE: The power output specification, 1800W on this model is measured with IEC measurement. The power output is measured with two(2) liters water is equiva- lent to 1800W in measurement with IEC, when mea- sured with the following power output. (1)1. Fill two beakers, one liter of tap water respec- tively 2. Use an accurate thermometer and measure each water temperature respectively. (2) Place beakers side by side in center of the ceramic tray. (3) Close the door,set the “TIME” for two minutes. Touch the “START” key and heat the water for exactly two minutes. (4)Take the beakers out, immediately stir the water and measure the water temperatures respectively. (5) Calculate the temperature rise of water in each beaker. Then calculate the average value of the two temperature rises.( ƒ¢t) (6) The teperature rise shall be in the following range; Average Temp. Rise Minimum 23.1°C Maximum 28.3°C Power output is affected by the line voltage under load. (7) For correct Power output measurement, the line voltage under load must be 208±2Volts. 4.PRECATIONS AND REPAIR SERVICE TIPS PRELIMINARY