F: Noise Filter Test; G: Touch Control Panel Assembly Test - Sharp R-350Y Service Manual

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Table of Contents

R-350Y(S)

[6] F: NOISE FILTER TEST

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.

MEASURING POINT

Between N and L

Between terminal N and WHITE

Between terminal L and RED

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

CARRY OUT 4R CHECKS.

[7] G: TOUCH CONTROL PANEL ASSEMBLY TEST

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, and also the Control Unit is divided into two units, CPU Unit and Power Unit, and 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 control unit assembly.

1) When touching the pads, a certain pad produces no signal at all.

2) When touching a number pad, two figures or more are displayed.

3) 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 ([8] H) to determine if control

unit is faulty.

1) In connection with pads.

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) In connection with indicators.

a) At a certain digit, all or some segments do not light up.

b) At 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.

f) A certain group of indicators do not light up.

g) The figure of all digits flicker.