R-3A54
R-3E54
TEST PROCEDURES (CONT’D)
PROCEDURE
LETTER COMPONENT TEST
I
LIVE TEST FOR MOTOR WINDINGS
CAUTION: The following procedure requires the oven to be connected to the supply
and should only be used if the relevant “cold” checks for the motor un-
der test are inconclusive.
1. CARRY OUT3JCHECKS
2. Disconnect the leads from the primary of the power transformer. Make sure that the leads
remain isolated from other oven components and chassis. (Use insulation tape if necessary,)
3. Connect a voltmeter, set to 250V AC, across the motor terminals. (Refer to the relevant motor
test procedure or pictorial diagram for the correct terminal numbers.)
4. Arrange the meter in a position where it can be read during the test. (Do not touch the meter,
meter leads or oven circuitry while the oven is active.)
5. Close the oven door.
6. Set the relevant timer for about three (3) minutes, set the power level to HIGH and push the
START button.
7. Note the reading on the meter and carefully observe the motor under test to see if it is turning.
8. CARRY OUT 3D CHECKS
9. Remove test meter leads.
1 O.Reconnect the leads to the primary of the power transformer.
If a reading of 240 volts AC was obtained (step 7) but the motor was not turning then it is faulty
and should be replaced. If the meter indicated that no supply was present then the wiring to the
motor should be checked for continuity.
J
BLOWN FUSE F M8A
CARRY OUT 3D CHECKS
1. If the fuse M8A is blown, there could be a shorts or ground in electrical parts or wire harness.
Check them and replace the defective parts or repair the wire harness.
2. If the fuse M8A is blown when the door is opened, check the 1st latch switch, 2nd latch
switch, monitor switch and monitor resistor.
If the fuse M8A is blown by incorrect door switching replace the defective switch(s) and the
fuse M8A.
3. If the fuse M8A is blown, there could be a short in the asymmetric rectier or there could be
a ground in wire harness.
A short in the asymmetric rectifier may have occured due to short
or ground in H.V. rectifier, magnetron, power transformer or H.V. wire. Check them and re-
place the defective parts or repair the wire harness.
CARRY OUT 4J CHECKS
CAUTION: Only replace 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 di-
vided into two units, Control Unit ‘and Key Unit, and troubleshooting by unit replacement is de-
scribed according to the symptoms indicated.
1. Key Unit.
The following symptoms indicate a defective key unit. Replace the key un t.
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, Replace the COI
2-l In connection with pads.
trol unit.
a) When touching the pads, a certain group of pads do not produce a signal.
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