15
R-7A55(W)/(B)
R-7E45(W)/(B)
COMPONENT TEST
TEST PROCEDURES (CONT'D)
G
THERMAL CUT-OUT TEST
PROCEDURE
LETTER
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.
CARRY OUT 4R CHECKS
If incorrect readings are obtained, replace the thermal cut-out.
An open circuit thermal cut-out (MG) TC1 indicates that the magnetron has overheated, this may be due
to resistricted ventilation, cooling fan failure.
An open circuit thermal cut-out (OVEN) TC2 indicates that the oven cavity has overheated, this may be
due to no load operation.
An open circuit thermal cut-out (CONV.) TC3 indicates that the convection fan motor winding has
overheated, this may be due to resisted ventilation or locked cooling fan or locked convection fan motor.
Table: Thermal Cut-out Test
Temperature of
Temperature of
Indication of
"ON" condition
"OFF" condition
ohmmeter
Parts Name
(closed circuit).
(open circuit).
(When room
(˚C)
(˚C)
temperature is
approx. 20˚C.)
Thermal cut-out
This is not resetable
Above 170˚C
Closed circuit
170˚C TC1
type.
Thermal cut-out
This is not resetable
Above 125˚C
Closed circuit
125˚C TC2
type
Thermal cut-out
Below 170˚C
Above 190˚C
Closed circuit.
190˚C TC3
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.
I
NOISE FILTER TEST
CARRY OUT 3D CHECKS
Disconnect the leads from the terminals of
noise filter.
Using an ohmmeter, check between the ter-
minals as described in the following table.
L
N
L
L
15A
Cx
Cy
RED
WHT
F6.3A
R1
R2
If incorrect readings are absorbed, replace the noise filter unit.
CARRY OUT 4R CHECKS
MEASURING POINTS
INDICATION OF OHMMETER
Between N and L
Approx. 680 k
Ω
Between terminal N and WHITE
Short circuit
Between terminal L and RED
Short circuit
L (min)
Cx
±
20%
Cy
±
20%
1.0mH
0.22
µ
F
4700pF
R1: 10 M
Ω
±
20%
R2 : 680 k
Ω
±
20%
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS
Table: Resistance of Motor
Motors
Resistance
Fan motor
Approximately 182
Ω
Turntable motor
Approximately 16 k
Ω
Convection fan motor
Approximately 163
Ω
Damper motor
Approximately 16 k
Ω
