Sharp R-763IN Service Manual page 17

TEST PROCEDURES
PROCEDURE
LETTER
I 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.
If incorrect readings are obtained, replace the noise filter unit.
CARRY OUT 4R CHECKS
K MOTOR WINDING 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.
If incorrect readings are obtained, replace the motor.
CARRY OUT 4R CHECKS
L GRILL HEATING ELEMENT TEST
CARRY OUT 3D CHECKS
Before carrying out the following tests make sure the heating element is cool completely.
1. Resistance of heating element
Disconnect the wire leads to the heating element to be tested. Using ohmmeter with low resistance
range. Check the resistance across the terminals of the heating element as described in the following
table.
Grill heating element
2. Insulation resistance
Disconnect the wire leads to the heating element to be tested, Check the insulation resistance
between the element terminal and cavity using a 500V - 100MΩ insulation tester. The insulation
resistance should be more than 10MΩ in the cold start.
If the results of above test 1 and/or 2 are out of above specifications, the heating element is probably
faulty and sholud be replaced.
CARRY OUT 4R CHECKS
MEASURING POINTS
Between N and L
Between terminal N and WHITE
Between terminal L and RED
Motors
Fan motor
Turntable motor
Parts name
R-763 -
COMPONENT TEST
N
L
Table: Resistance of Motor
Approximately 290Ω
Approximately 14.6Ω
Table: Resistance of heating element
Approximately 22.5Ω x 2 = 45Ω
15
WHT
L
R1
RED
L
R2 Cy
Cx
R1: 10M ohm ± 20%
R2: 680K ohm ± 20%
F8A
Cx ± 20% Cv ± 20%
L(min)
1.0mH 0.22µF 0.0047µF
INDICATION OF OHMMETER
Approx. 680K ohm
Short circuit
Short circuit
Resistance
Resistance