GE JVM1790SK Service Manual - Page 11

GENERAL INFORMATION FOR SERVICE GENERAL PRECAUTIONS IN USE A. Never operate the unit when it is empty. Operating the oven with no load may shorten the life of the magnetron. Whenever cooking dry foods (dried fish, bread, etc.) or a small amount of food, be sure to put a glass of water into the cooking compartment. The glass turntable may become hot after operating, be careful when touching it. B. Aluminum foil should be avoided because it will disrupt cooking and may cause arcing. However, small pieces may be used to cover some parts of food to slow the cooking. Any aluminum foil used should never be closer than 2.5 cm to any side wall of the oven. TRIAL OPERATION After installation, the following sequences and results should be checked carefully. A. Put a container filled with water (about 1 liter) into the oven, and close the door tightly. B. Set cooking time for 10 minutes by touching "1" and then "0" three times. "1, 0, 0, 0" appears in the display window. C. Touch the START key. Make sure the cavity light comes on. The unit will begin cooking and the display window will show the time counting down by seconds. D. After about 5 minutes, make sure the primary interlock switch, the secondary interlock switch and the interlock monitor switch operate properly by opening and closing the door several times. Touch the START key each time the door is closed. E. Continue operating the unit. Four long beep sound signal is heard when the time is up. The unit will shut off automatically. F. Confirm the water is hot. G. Finally, measure the output power according to "POWER OUTPUT MEASUREMENT" on page 7-3. FEATURES AND SPECIFICATIONS FEATURES A. The safety systems incorporated in this model are: (1) Primary interlock switch (2) Secondary interlock switch (3) Interlock monitor switch (4) Choke system (5) Magnetron thermostat (6) Oven cavity thermostat (Note: This thermostat located on the oven cavity will open and stop the unit from operation only if a high temperature is reached, such as, a fire created by overcooking food.) B. Any one of 10 power output levels ranging 100W to 1000W can be selected by the touch control and electronic computer system. STANDARD TEST LOAD The standard test load is one liter (1000ml.) water with starting temperature of 59°F ~ 75°F in a 1000ml beaker. (DO NOT USE ANY OTHER LOAD OR DISH AS RESULTS WILL VARY FROM STANDARD.) PERFORMANCE TEST FOR MICROWAVE 1. Use Glass Tray and the beaker WB64 x 0073. 2. Record initial water temperature. 3. Run at high power for 2:03. 4. Record end water temperature. The minimum difference between the initial and ending temperature should be: 38°F @ 120V TO PREVENT ELECTRICAL SHOCK. USE EXTREME CAUTION WHEN DIAGNOSING OVEN WITH OUTER CASE REMOVED AND POWER "ON". THE HIGH VOLTAGE SECTION OF THE POWER SUPPLY INCLUDING FILAMENT LEADS IS 4000 VOLTS POTENTIAL WITH RESPECT TO GROUND. 6-1