Sharp R-340A, Service Manual

Page: 13 / 36

R-340A
11
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the motor.
Using an ohmmeter, check the resistance between the two terminals as described in the table below.
Table: Resistance of Motor
Motors Resistance
Fan motor Approximately 390
Ω
Turntable motor Approximately 16.08 k
Ω
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS.
H MOTOR WINDING TEST
CARRY OUT 3D CHECKS.
1. If the fuse M10A is blown, there could be 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 M10A is blown when the door is opened, check the 1st. latch switch, 2nd. interlock relay,
2nd. interlock relay control switch, monitor switch and monitor resistor.
If the fuse M10A is blown by incorrect door switching replace the defective switch(s) and the fuse
M10A.
CARRY OUT 4R CHECKS.
CAUTION: ONLY REPLACE FUSE M8A WITH THE CORRECT VALUE REPLACEMENT.
I BLOWN FUSE F M10A
J NOISE FILTER TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the terminals of the noise
filter. Using an ohmmeter, check between the termi-
nals as described in the following table.
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
If incorrect readings are obtained, replace the noise filter unit.
CARRY OUT 4R CHECKS.
N
L
Cx
L
L
Cy
WHT
RED
L (min) Cx
±
20% Cy
±
20%
600
µ
H 0.068
µ
F 0.0022
µ
F
K 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 REPLACE-
MENT.