15
R-25AM
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
3. CARRY OUT 4R CHECKS.
CAUTION: IF THE temperature fuse INDICATES AN OPEN CIRCUIT AT ROOM TEMPERATURE,
REPLACE temperature fuse.
1. CARRY OUT 3D CHECKS.
2. Follow the procedures below for each thermistor.
2-1. THERMISTOR TEST
Disconnect the connector of the thermistor from the switch harness. Measure the resistance of the
magnetron thermistor with an ohmmeter. Connect the ohmmeter leads to the leads of the thermistor.
Resistance:
Approx. 500 k
Ω
-- 1 M
Ω
If the meter does not indicate above resistance, replace the thermistor.
3. CARRY OUT 4R CHECKS.
I
THERMISTOR TH1, TH2, TH3 TEST
Open
Close
Display or
temperature
temperature
Condition
Check point
Magnetron tem-
perature fuse (Up-
per) TF1
Magnetron tem-
p e r a t u r e f u s e
(Lower) TF2
Exhaust tempera-
ture fuse TF3
150˚C
120˚C
Non resetable
type
Non resetable
type
EE1
EE3
EE2
Oven shut
off
Magnetron MG1 Failure:
Test magnetron MG1 and Blower motor.
Magnetron MG1, MG2 Failure: Test magnetron MG1,
MG2. Check blower motor and ventilation opening.
Magnetron MG2 Failure:
Test magnetron MG2 and Blower motor.
Food has been burned in oven.
Temperature of oven inside is very high.
J
MOTOR WINDING TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the motor. Using an ohmmeter, check the resistance between the two
terminals.
Resistance of Blower motor should be approximately 60
Ω
.
Resistance of Antenna motor should be approximately 8.8 k
Ω
.
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS.
If incorrect readings are absorbed, replace the noise filter.
CARRY OUT 4R CHECKS.
K
NOISE FILTER TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of noise filter. Using an ohmmeter, check between the
terminals as described in the following table.
MEASURING POINT
INDICATION OF OHMMETER
Between N and L
Approx. 680 k
Ω
Between terminal N and WHIT
Short circuit
Between terminal L and BLK
Short circuit
F3 : WEAK POINT
NOISE FILTER
NOISE SUPPRESSION COIL
DISCHARGE RESISTOR 680 k
Ω
1/2W
DISCHARGE RESISTOR 10 M
Ω
1/2W
LINE CROSS CAPACITOR 0.22
µ
F/ AC250V
LINE CROSS CAPACITOR
10000 pF/ AC250V
LINE CROSS CAPACITOR
10000 pF/ AC250V
L
BLK
WHT
N
L
HIGH VOLTAGE FUSE F4, F5 TEST
CARRY OUT 3D CHECKS.
If the high voltage fuse F4 (or F5) is blown, there could be a short in the high voltage rectifier or the magnetron
MG1 (or MG2). Check them and replace the defective parts and the high voltage fuse F4 (or F5).
CARRY OUT 4R CHECKS.
CAUTION:
Only replace high voltage fuse with the correct value replacement.
