Maytag AMC4080AAB/W/Q/S, Service Manual

Page: 10 / 53

Troubleshooting Procedures
!
WARNING
To avoid risk of electrical shock, personal injury or death; disconnect power to oven and discharge the high voltage
capacitor before servicing, unless testing requires power.
10 16022923 Rev. 0
©2004 Maytag Services
CAUTION
!
• Verify proper grounding before checking for trouble.
• Be careful of the high voltage circuit.
• Discharge the high voltage capacitor.
• When checking the continuity of the switches or of the high voltage transformer, disconnect one lead wire from
these parts and then check continuity with the AC plug removed. To do otherwise may result in a false reading
or damage to your meter.
•
Do not touch any part of the circuit on the printed circuit board, since static electric discharge may damage the
control panel. Always touch yourself to ground while working on this panel to discharge any static charge built
up in your body.
Problem Possible Cause Correction
No display and no
operation
(fuse tests OK)
Open or loose lead wire harness....................
Open thermal cutout (magnetron)
Open low voltage transformer
Defective Assembly PCB ...............................
•
Check wire harness, thermal cutout
and low voltage transformer for loose
wires and continuity, tighten wires
where necessary or replace failed
component, if necessary. If thermal
cutout is replaced, check fan motor.
Replace if necessary.
•
Check Assembly PCB. Also, if low
voltage transformer is defective,
check/replace PCB.
No display and no
operation
(fuse blown) Shorted lead wire harness..............................
Defective primary switch
Defective monitor switch
Shorted high voltage capacitor.......................
Shorted high voltage transformer
•
Check adjustment of primary switch,
monitor switch, power relay, door
sensing switch. Readjust/replace if
necessary. The primary, secondary
and monitor switch must be replaced
at the same time.
•
Check measurement of high voltage
capacitor and high voltage
transformer. Replace if necessary. If
high voltage transformer is replaced,
check magnetron and diode.
Cannot program
oven Key input is not in-sequence ..........................
Open or loose membrane key pad to
Assembly PCB connection .............................
Membrane panel shorted or open
Defective Assembly PCB ...............................
•
See Operation Procedure and verify
program sequence
•
Check connections of membrane
keypad to Assembly PCB,
tighten/reconnect where necessary.
•
Replace Assembly PCB