R-895M - 15
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS.
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of the thermal cut-out. Then using an ohmmeter, make a
continuity test across the two terminals as described in the below.
Table: Thermal Cut-out Test
Temperature of "ON"
Temperature of "OFF"
Indication of ohmmeter
Parts Name
condition (closed circuit).
condition (open circuit). (When room temperature
(
˚
C)
(
˚
C)
is approx. 20
˚
C.)
Thermal cut-out 125
˚
C
This is not resetable
Above 125
˚
C
Closed circuit
Thermal cut-out 145
˚
C
Below 115
˚
C.
Above 145
˚
C
Closed circuit
If incorrect readings are obtained, replace the thermal cut-out.
An open circuit thermal cut-out (MG) indicates that the magnetron has overheated, this may be due to
resistricted ventilation, cooling fan failure.
An open circuit thermal cut-out (OVEN) indicates that the oven cavity has overheated, this may be due
to no load operation,or excessive heat / fire inside the oven.
CARRY OUT 4R CHECKS.
E
SWITCH TEST
Table: Terminal Connection of Switch
Plunger Operation
COM to NO
COM to NC
Released
Open circuit
Short circuit
Depressed
Short circuit
Open circuit
COM; Common terminal,
NO;
Normally open terminal
NC;
Normally close terminal
If incorrect readings are obtained,replace the switch.
CARRY OUT 4R CHECKS.
CARRY OUT 3D CHECKS.
Isolate the switch to be tested and using an ohmmeter check between the terminals as described in
the following table.
F
THERMISTOR TEST
CARRY OUT 3D CHECKS.
Disconnect the connector B from CPU unit. Measure the resistance of the thermistor with an
ohmmeter. Connect the ohmmeter leads to Pin No's C1 and C3 of the thermistor harness.
Room Temperature
Resistance
20
˚
C - 30
˚
C
Approximately 359.9 k
Ω
- 152 k
Ω
If the meter does not indiicate above resistance, replace the thermistor.
CARRY OUT 4R CHECKS.
PROCEDURE
LETTER
COMPONENT TEST
G
THERMAL CUT-OUT TEST
H
MOTOR WINDING TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the motor. Using an ohmmeter, check the resistance between the two
terminals as described in the table below.
Table: Resistance of Motor
Motors
Resistance
Fan motor
Approximately
293
Ω
Turntable motor
Approximately
15 k
Ω
Convection fan motor
Approximately
288
Ω
TEST PROCEDURES
