R-658WM - Sharp Home Appliance Service Manual (repair manual). Page 15

R65

8WM

8 – 5

CARRY OUT 3D CHECKS.

Remove the outer case and check voltage between Pin No. 1 and Pin No. 3 of the 3 pin connector (A) on the control unit with an A.C. voltmeter.

The meter should indicate rated voltage, if not check oven circuit.

RY1, RY2, RY3 and RY4 Relay Test

These relays are operated by D.C. voltage

        DC. voltage indicated ................................... Defective relay.

        DC. voltage not indicated ............................. Check diode which is connected to the relay coil. If diode is good, control unit is defective.

CARRY OUT 4R CHECKS.

To protect the electronic circuits, this model is provided with a fine foil pattern added to the input circuit on the PWB, this foil pattern acts as a fuse. If
the foil pattern is open, follow the troubleshooting guide given below for repair.

CARRY OUT 3D CHECKS.

NOTE: *At the time of these repairs, make a visual inspection of the varistor. Check for burned dam-

age. If any abnormal condition is detected, replace the control unit.

CARRY OUT 4R CHECKS.

RELAY SYMBOL

OPERATIONAL VOLTAGE

CONNECTED COMPONENTS

RY1

APPROX. 12V D.C.

Oven lamp / Turntable motor

RY2

APPROX. 12V D.C.

Grill heating element

RY3

APPROX. 12V D.C.

High voltage transformer

RY4

APPROX. 12V D.C.

Fan motor

STEPS

OCCURRENCE

CAUSE OR CORRECTION

1

The rated AC voltage is not present between Pin No. 1 of the 3-pin connec-
tor (A).

Check supply voltage and oven power cord.

2

The rated AC voltage is present at primary side of low voltage transformer.

Low voltage transformer or secondary circuit defective.
Check and replace control unit.

3

Only pattern at “a” is broken.

*Insert jumper wire J1 and solder. 
 (CARRY OUT 3D CHECKS BEFORE REPAIR)

4

Pattern at “a” and “b” are broken.

Replace control unit. 
(CARRY OUT 3D CHECKS BEFORE REPAIR)