Troubleshooting - Samsung M171FN Service Manual

6. Troubleshooting

4000 VOLTS EXIST AT THE HIGH VOLTAGE AREA. DO NOT OPERATE THE OVEN WITH
CABINET PARTS REMOVED. DO NOT REMOVE THE CABINET PARTS IF THE POWER SUPPLY
CORD IS PLUGGED IN THE WALL OUTLET. UNPLUG THE POWER CORD BEFORE SERVICING.
6-1 Electrical Malfunction
Parts Cause
Defective primary
interlock switch
Fuse blows
are winding.
out when
door is
opened.
Defective interlock
monitor switch
Layer short of the
Fuse is
secondary coil of
Open
H. V. Transformer
1) Fuse blown out
2) Poor contact of
power cord.
Oven lamp
3) Defective lamp
does not
4) Defective timer
light.
contacts
5) Thermal cutout
S/W open
1) Defective fan
motor.
Fan does
not operate.
2) Defective con-
tacts of timer
NOTE: Interlock monitor switch must be replaced when the fuse is blown out.
WARNING FOR HIGH VOLTAGE
Diagnosis
Check continuity of the primary switch terminals
with wire removed using a multimeter. If there is
continuity inter between switch terminals when door
is opened,the switch is defective.
Check continuity of the monitor switch terminals
with wire removed by using a multimeter.
If there is continuity between switch terminals the
door is closed, the switch is defective.
The fuse will not blow right away, but if it blows in
a few seconds, then there is a layer short If the
fuse blows with H. V. Trans secondary open, the
transformer may be faulty.
Check fuse.
Check continuity of power supply cord. Also
check whether the power cord is securely wired.
The fan motor rotates, but lamp does not light.
Check the terminals of timer for continuity,turning
the timer knob ON and OFF repeatedly.
In this case the oven lamp and fan do not turn on
If 230V is found at motor terminals, the motor
should be replaced.
The oven lamp does not light and fan motor does
not operate.
- 1 3 -
Remedy
Replace the primary
interlock switch
Replace the interlock
monitor switch
Replace H. V.Transformer
Replace the fuse.
Adjust or replace
the power supply cord
Replace the lamp.
Replace the timer.
Replace the thermal
cutout S/W
Replace the motor.
Replace the timer.