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PROCEDURE
LETTER
3.
Power Unit or Touch Control Transformer
a)
b)
When testing is completed,
1)
Disconnect the power supply cord, and then disassemble as per "Drawer Microwave Disas-
sembly" Page 4-6.
2)
Open the drawer and block it open.
3)
Discharge high voltage capacitor.
4)
Reconnect all leads removed from components during testing.
5)
Re-install the covers.
6)
Reconnect the power supply cord after the covers are installed.
7)
Run the oven and check all functions.
B
KEY UNIT TEST
1.
Disconnect power supply cord, and then remover outer case.
2.
Open the drawer and block it open.
3.
Discharge high voltage capacitor.
4.
If the display fails to clear when the STOP/CLEAR pad is depressed,
¿ rst verify the À at ribbon cable is making good contact, verify that the
door sensing switch (stop switch) operates properly; that is the con-
tacts are closed when the drawer is closed and open when the draw-
er is open. If the door sensing switch (stop switch) is good, discon-
nect the À at ribbon cable that connects the key unit to the control unit
and make sure the drawer sensing switch is closed (either close the
drawer or short the door sensing switch connecter). Use the Key unit
matrix indicated on the control panel schematic and place a jumper
wire between the pins that correspond to the STOP/CLEAR pad mak-
ing momentary contact. If the control unit responds by clearing with
a beep the key unit is faulty and must be replaced. If the control unit
does not respond, it is faulty and must be replaced. If a speci¿ c pad
does not respond, the above method may be used (after clearing the
control unit) to determine if the control unit or key pad is at fault.
5.
Reconnect all leads removed from components during testing.
6.
Re-install the outer case (cabinet).
7.
Reconnect the power supply cord after the outer case is installed.
8.
Run the oven and check all functions.
C
RELAY TEST
1.
Disconnect the power supply cord, and then remove outer case.
2.
Open the door and block it open.
3.
Discharge high voltage capacitor.
4.
Disconnect the leads to the primary of the power transformer.
5.
Ensure that these leads remain isolated from other components and oven chassis by using insu-
lation tape.
6.
After that procedure, re-connect the power supply cord.
7.
Remove the outer case and check voltage between Pin Nos. 5 and 7 of the 4 pin connector (CN-
A) on the power unit with an A.C. voltmeter.
The meter should indicate 120 volts, if not check oven circuit.
RY6-5, RY2, RY3 and RY4 Relay Test
These relays are operated by D.C. voltage
Check voltage at the relay coil with a D.C. voltmeter during the microwave cooking operation.
DC. voltage indicated
DC. voltage not indicated
Drawer Microwave
TEST PROCEDURES
Fan motor, stirrer motor, oven lamp or electrical parts do not turn on or do not turn off.
Digital display on the control unit does not show anything.
Defective relay.
Check diode which is connected to the relay coil. If diode is good,
control unit is defective.
COMPONENT TEST
6-5
Troubleshooting
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