R-795M (serv.man16). Complete - Sharp Home Appliance Service Manual (repair manual). Page 15

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R-795M- 
15
PROCEDURE
LETTER
COMPONENT TEST
J
BLOWN FUSE 20A
I
NOISE FILTER TEST
CARRY OUT 3D CHECKS.
Disconnect the leads from the noise filter terminals.
Using an ohmmeter, check between the terminals as
described in the following table.
CARRY OUT 3D CHECKS.
If the fuse 20A 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 
with
 the correct value replacement.
K
BLOWN FUSE F8A
CARRY OUT 3D CHECKS.
1. If the fuse F8A  is blown when the door is opened, check the monitored latch switch and monitor
switch.
2. If the fuseF8A is blown by incorrect door switching replace the defective switch(es) and the  fuse
F8A.
3. If the fuse F8A is blown, there could be shorts in the asymmetric rectifier or there is a ground in wire
harness. A short in the asymmetric rectifier may be occurred due to short or ground in H.V. rectifier,
magnetron, high voltage transformer or H.V. wire. Check them and replace the defective parts or
repair the wire harness.
CARRY OUT 4R CHECKS.
CAUTION:
Only replace fuse 
F8A
 with the correct value replacement.
L
GRILL HEATING ELEMENT (TOP) AND BOTTOM HEATING ELEMENTS 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.
Table: Resistance of heating element
Parts name
Resistance
Grill heating element (top)
Approximately 46 Ω
Bottom heating element
Approximately 92 Ω
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 10 MΩ 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 should be replaced.
CARRY OUT 4R CHECKS.
MEASURING POINTS
INDICATION OF OHMMETER
Between N and L
Approx. 680 kΩ
Between terminal N and WHITE
Short circuit
Between terminal L and RED
Short circuit
If incorrect readings are abtained, replace the noise filter unit.
CARRY OUT 4R CHECKS.
L (min)
Cx ± 20%
Cy ± 20%
R1
R2
1.0mH
0.22µF
4700pF
10 MΩ
680kΩ
F8A
20A
WHT
RED
R1
R2
N
Cx
Cy
L
L
L
TEST PROCEDURES
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