R-21FBSTM - Sharp Home Appliance Service Manual (repair manual). Page 12

R-21FBSTM/R-22FBSTM - 12

Cx

Cy

Rx

Ry

Cy

L

L

RED

WHT

 F8A

L

N

Cx

Rx

CARRY OUT 3D CHECKS

Disconnect the leads from the terminals of
the noise filter.
Using an ohmmeter, check between the ter-
minals as described in the following table.

Between N and L

Open circuit

Between terminal N and WHITE

Short circuit

Between terminal L and RED

Short circuit

Rx 

±

5%

L(min)

Cx 

±

 20%

Cy 

±

 20%

Ry 

±

5%

680k

Ω

1.0mH

0.22

µ

F

0.0033

µ

F

10M

Ω

If correct readings are obtained, replace the noise filter unit.

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.

CARRY OUT 4R CHECKS

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 125˚C

Closed circuit

125˚C TC01

 type

Thermal cut-out

This is not resetable

 Above 125˚C

Closed circuit

125˚C TC02

type

If incorrect readings are obtained, replace the thermal cut-out.
An open circuit thermal cut-out (MG)  TC02 indicates that the magnetron has overheated, this may be
due to resistricted ventilation, cooling fan failure.
An open circuit thermal cut-out (OVEN) TC01 indicates that the oven cavity has overheated, this may
be due to no load operation.

CARRY OUT 3D CHECKS.
If the fuse F8A  (F1) is blown when the door is opened, check the primary latch switch, monitor switch
and monitor resistor.

If the fuse F8A  (F1) is blown by incorrect door switching replace the defective switch(es) and the  fuse
F8A  (F1).

CARRY OUT 4R CHECKS.