R-247. Complete - Sharp Home Appliance Service Manual (repair manual). Page 12

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FUSE
T6.3A

N

L

LINE CROSS CAPACITOR

0.068

µ/AC250V 

NOISE SUPPRESSION COIL 

LINE BYPASS
CAPACITOR
0.0022

µ/AC250V

LINE BYPASS
CAPACITOR
0.0022

µ/AC250V

NOISE FILTER

WHT

RED

If the fuse T6.3A is blown by incorrect door switching, replace the defective switch(es) and the fuse T6.3A.

If the fuse T6.3A is blown, there is a shorts or grounds in electrical parts or wire harness.
Check them and replace the defective parts or repair the wire harness.

CARRY OUT 4R CHECKS.

CARRY OUT 3D CHECKS.

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

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

MEASURING POINT

INDICATION OF OHMMETER

Between N and L

Open circuit

Between terminal N and WHITE

Short circuit

Between terminal L and RED

Short circuit

CARRY OUT 3D CHECKS.
If the high voltage fuse is blown, there could be a short in the high voltage rectifier or the magnetron.
Check them and replace the defective parts and the high voltage fuse.

CARRY OUT 4R CHECKS.

CAUTION: ONLY REPLACE HIGH VOLTAGE FUSE WITH THE CORRECT VALUE REPLACE-

MENT.

The touch control panel consists of circuits including semiconductors such as LSI, ICs, etc. Therefore,
unlike conventional microwave ovens, proper maintenance cannot be performed with only a
voltmeter and ohmmeter.
In this service manual, the touch control panel assembly is divided into two units, Control Unit and
Key Unit, troubleshooting by unit replacement is described according to the symptoms indicated.
1.  Key Unit.  Note : Check key unit ribbon connection before replacement.

The following symptoms indicate a defective key unit. Replace the key unit.

a) When touching the pads, a certain pad produces no signal at all.
b) When touching a number pad, two figures or more are displayed.
c) When touching the pads, sometimes a pad produces no signal.

2. Control Unit.

The following symptoms indicate a defective control unit. Before replacing the control unit, perform
the key unit test (Procedure L) to determine if control unit is faulty. Replace the control unit.

2-1  Programming problems.

a) When touching the pads, a certain group of pads do not produce a signal.
b) When touching the pads, no pads produce a signal.

2-2 Display problems.

a) For a certain digit, all or some segments do not light up.
b) For a certain digit, brightness is low.
c) Only one indicator does not light up.
d) The corresponding segments of all digits do not light up; or they continue to light up.
e) Wrong figure appears.