Blown Monitor Fuse Test; Power Transformer Test - Wolf MWD30-2 Troubleshooting Manual

Drawer Microwave
PROCEDURE LETTER
L
M
(Models MWD24-2 / MWD30-2)

BLOWN MONITOR FUSE TEST:

1. Disconnect the power supply cord.
2. Open the drawer and block it open.
3. To discharge high voltage capacitor, wait for 60 seconds.
4. If the monitor fuse is blown when the drawer is opened, check the primary
interlock switch, secondary interlock switch and monitor switch according to
the "TEST PROCEDURE" for those switches before replacing the blown mon-
itor fuse.
Before replacing a blown monitor fuse, test the secondary interlock switch,
stop switch and monitor switch for proper operation.
If the monitor fuse is blown by improper switch operation, the monitor fuse and
monitor switch must be replaced with "monitor fuse and monitor switch assembly"
See Section 5, even if the monitor switch operates normally. The monitor fuse
and monitor switch assembly is comprised of a 20 ampere fuse and switch.
5. Reconnect all leads removed from components during testing.
6. Reassemble the unit.
7. Reconnect the power supply cord.
8. Run the oven and check all functions.

POWER TRANSFORMER TEST:

1. Disconnect the power supply cord.
2. Open the drawer and block it open.
3. Discharge high voltage capacitor.
4. Disconnect the primary input terminals and measure the resistance of the
transformer with an ohmmeter. Check for continuity of the coils with an ohm-
meter. On the R x 1 scale, the resistance of the primary coil should be less
than 1 ohm and the resistance of the high voltage coil should be approximate-
ly 90 ohms; the resistance of the filament coil should be less than 1 ohm.
5. Reconnect all leads removed from components during testing.
6. Reassemble the unit.
7. Reconnect the power supply cord.
8. Run the oven and check all functions.
HIGH VOLTAGES ARE PRESENT AT THE HIGH VOLTAGE TERMINAL, SO DO
NOT ATTEMPT TO MEASURE THE FILAMENT AND HIGH VOLTAGE.
5-15
COMPONENT TEST
#813632 - Revision B - December, 2009
Troubleshooting Guide