R-7N76(W)M
R-7N76(B)M
16
TEST PROCEDURES (CONT'D)
PROCEDURE
LETTER
COMPONENT TEST
CARRY OUT 3D CHECKS
If the fuse 13A 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 F2 M8A
CARRY OUT 3D CHECKS
1. If the fuse M8A is blown when the door is opened, check the 1st latch switch, monitor switch and
monitor resistor.
2. If the fuse M8A is blown by incorrect door switching replace the defective switch(es) and the fuse M8A.
3. If the fuse M8A is blown, there could be a shorts or grounds in electrical parts or wire harness.
Check them and replace the defective parts or repair the wire harness.
4. If the fuseM8A 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 M8A with the correct value replacement.
L
CONVECTION HEATING ELEMENT AND 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.
Table: Resistance of heating element
Parts name
Resistance
Convection heating element
Approximately 44
Ω
Grill heating element
Approximately 24
Ω
x 2 = 48
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 - 100M
Ω
insulation tester. The insulation
resistance should be more than 10M&ohm 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
J
FUSE 13A
M
THERMOSTAT TEST
CARRY OUT 3D CHECKS.
Disconnect connector-B from CPU unit. Measure the resistance of thermistor with an ohmmeter.
Connect the ohmmeter leads to Pin No's B5 and B6 of the thermistor harness.
Room Temperature
Resistance
20˚C - 30˚C
Approximately 326 k
Ω
- 175 k
Ω
