Read Panasonic NN-ST254MZPE Service Manual online
5-15
(TROUBLE 3) Display shows all figures set, but oven does not start cooking while
desired program times are set and START pad is touched.
(TROUBLE 4) Oven seems to be operation but output power is low.
CONDITION
CHECK
RESULT
CAUSE
REMEDY
1.Setting time does
not count down
when touching
START pad.
when touching
START pad.
2. Fan motor or
oven lamp
do not turn
on.
do not turn
on.
No continuity.
continuity.
No continuity.
Continuity.
Check the con-
nection between
connector and
P.C.B assembly.
nection between
connector and
P.C.B assembly.
Defective
secondary switch.
secondary switch.
Replace
secondary switch.
secondary switch.
Check continuity
of secondary
switch (with
door closed).
of secondary
switch (with
door closed).
Check fan motor.
Check oven lamp.
Abnormal.
Abnormal.
Normal.
Defective fan
motor.
motor.
Defective oven
lamp.
lamp.
Replace fan
motor.
motor.
Replace oven
lamp.
lamp.
Defective P.C.B
assembly.
assembly.
Replace P.C.B
assembly.
assembly.
Loose connection.
Loose connection.
Correct connection.
Connection then
tightly.
tightly.
CONDITION
CHECK
RESULT
CAUSE
REMEDY
Output is low.
Lower than 90% of
rating voltage.
rating voltage.
Normal.
Normal.
Abnormal.
Abnormal.
Measure the
output power.
output power.
Disconnect the
wire leads from
relay 2 and check
on and off time
with multitester.
wire leads from
relay 2 and check
on and off time
with multitester.
Defective P.C.B
assembly.
assembly.
Replace P.C.B
assembly.
assembly.
Decrease in power
source voltage
with load.
source voltage
with load.
Suggest customer
contact local
electric power
utility co. or
qualified
electrician.
contact local
electric power
utility co. or
qualified
electrician.
Check the
power source
voltage.
power source
voltage.
Defective
magnetron.
magnetron.
Replace
magnetron.
magnetron.
Normal.
Abnormal.
Check connection
between magnetron
filament terminals
and lead wires.
NOTE: Refer to Page 5-3 for measuring of microwave power output.
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