Key Unit Test - Wolf MWD24-2 Service Manual

Drawer Microwave
PROCEDURE LETTER
A
(Cont.)
B
(Models MWD24-2 / MWD30-2)
Power Unit or Touch Control Transformer:
1. Fan motor, stirrer motor, oven lamp or electrical parts do not turn on or do not
turn off.
2. Digital display on the control unit does not show anything.
When Testing is Completed:
1. Disconnect power supply cord, and then disassemble as per "Drawer
Microwave Disassembly" Section 4 Component Access Removal, 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.

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, first veri-
fy the flat ribbon cable is making good contact, verify that the door sensing
switch (stop switch) operates properly; that
is the contacts are closed when the drawer
is closed and open when the drawer is open.
If the door sensing switch (stop switch) is
good, disconnect the flat 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 making momentary con-
tact. 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 specific 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.
5-5
COMPONENT TEST
#813632 - Revision B - December, 2009
Troubleshooting Guide