Sharp R-210A, Service Manual

R-210A

11

TEST PROCEDURES

PROCEDURE

LETTER

COMPONENT TEST

CARRY OUT 3D CHECKS.

If the fuse 13A is blown when the door is opened, check the 1st latch switch, 2nd latch switch, monitor switch
and monitor resistor.

E

SWITCH TEST

Isolate the switch to be tested and using an ohmmeter check between the terminals as described in
the following table.

CARRY OUT 3D CHECKS.

Table: Terminal Connection of Switch

Plunger Operation

COM to NO

COM to NC

Released

O.C.

S.C.

Depressed

S.C.

O.C.

COM; Common terminal,
NO;     Normally open terminal
NC;     Normally close terminal
S.C.;   Short circuit
O.C.;   Open circuit

H

FUSE 13A

Table: Resistance of Motor

Motors

Resistance

Fan motor

Approximately 60 

Ω

Turntable motor

Approximately 3.4 k

Ω

If incorrect readings are obtained, replace the motor.

CARRY OUT 4R CHECKS.

G

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.

F

TEMPERATURE FUSE OR THERMAL CUT-OUT TEST

CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of the thermal cut-out or temperature fuse. Then using an
ohmmeter, make a continuity test across the two terminals as described in the below.

CARRY OUT 4R CHECKS.

Temperature of "ON"

Temperature of "OFF"

Indication of ohmmeter

Parts Name

condition (closed circuit).

condition (open circuit).

(When room temperature is approx. 20˚C.)

Temp. fuse 120˚C

This is not resetable type. Above 120˚C

Closed circuit

Thermal cut-out 95˚C

Below 75˚C

Above 95˚C

Closed circuit.

Table: Temperature Fuse or Thermal Cut-out Test

If incorrect readings are obtained, replace the temperature fuse or 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 temperature fuse (OVEN) indicates that the food in the oven cavity may catch fire, this
may be due to overheating produced by improper setting of the cooking time or failure of the control
panel.

If incorrect readings are obtained, make the necessary switch adjustment or replace the switch.

CARRY OUT 4R CHECKS.

F. When the internal wire is opened in the high voltage capacitor shows an infinite resistance.
G. The resistance across all the terminals and the chassis must be infinite when the capacitor is

normal.

If incorrect reading are obtained, the high voltage capacitor must be replaced.

CARRY OUT 4R CHECKS.