Daewoo KOT-150S0A, Service Manual, Page: 34 / 72

33
TROUBLE SHOOTING GUIDE
Following the procedures below to check if the oven is defective or not.
1. Check grounding before checking trouble.
2. Be careful of the high voltage circuit.
3. Discharge the high voltage capacitor.
4. When checking the continuity of the switches, fuse or high voltage transformer, disconnect one lead wire from these parts
and the check continuity with the AC plug removed. To do otherwise may result in a false reading or damage to your
meter.
5. Do not touch any part of the circuit on the touch control circuit since static electric discharge may damage this control
panel. Always touch yourself to ground while working on this panel to discharge any static charge built up in your body.
First of all, operate the microwave oven following the correct operation described in users guide manual (instruction
manual) by time cooking in order to find the exact cause of any trouble.
(TROUBLE 1) Oven does not operate at all; any input can not be accepted.
CONDITION CHECK
Check continuity of
interlock monitor
switch with door
closed (COM NC)
Check continuity of
primary interlock
switch contact with
door partially open
until interlock
monitor switch
contact close
(COM NC close)
Malfunction of
interlock monitor
switch
RESULT
continuity
No Continuity
CAUSE REMEDY
Replace(NOTE1)
Fuse blows
Shorted contacts
of primary
interlock switch
continuity Replace(NOTE1)
Check continuity of
primary winding of
low voltage
transformer
Disconnect one
side of the lead
wire connected
from high voltage
to high voltage
Capacitor and
operate the unit
Shorted or open
winding
0 or infinite
Approx.90~110
Replace low
Voltge transformer
Defective low
voltage capacitor
Defective high
voltage capacitor
Normal
Fuse again blows
Replace
Replace
NOTE1
All these switches must be replaced at the same time, plese refer to page 14 and 15 for adjustment
instructions.