Sharp R-27STM Service Manual page 10

R-27STM
H: FUSE T6.3A
CARRY OUT 3D CHECKS.
If the fuse T6.3A is blown when the door is opened, check the 1st. latch switch, relay (RY1), 2nd. interlock relay (RY2) and monitor
switch.
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.
CAUTION: ONLY REPLACE FUSE T6.3A WITH THE CORRECT VALUE REPLACEMENT.
I: NOISE FILTER TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of the noise filter. Using an ohmme -
ter, 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.
J: HIGH VOLTAGE FUSE TEST
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 REPLACEMENT.
K: 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 Switch Unit, and also the Control Unit is divided into two units, CPU Unit and Pow -
er Unit, and troubleshooting by unit replacement is described according to the symptoms indicated.
1. Switch Unit. Note: Check switch unit wire harness connection before replacement.
The following symptoms indicate a defective switch unit. Replace the switch unit.
a) When touching the buttons, a certain button produces no signal at all.
b) When touching the buttons, sometimes a button produces no signal.
c) When rotating the TIMER/WEIGHT knob, the cooking time or the weight can not be input.
2. Control Unit.
The following symptoms indicate a defective control unit. Before replacing the switch unit, perform the Switch unit test (Procedure L)
to determine if control unit is faulty.
2 -1. In connection with buttons.
a) When touching the buttons, a certain group of buttons do not produce a signal.
b) When touching the buttons, no buttons produce a signal.
2 -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.
3. Other possible troubles caused by defective control unit.
a) Buzzer does not sound or continues to sound.
b) Clock does not operate properly.
c) Cooking is not possible.
R27STM.indd 10
INDICATION OF OHMMETER
Open circuit
Short circuit
Short circuit
10
NOISE FILTER
N
NOISE SUPPRESSION COIL
WHT
L
FUSE
T6.3A
RED
11/3/08 2:04:26 PM