Sharp R-306LK Service Manual page 20

R306LW
5) Make a visual inspection of the varistor. Check for burned damage and examine the
transformer with a tester for the presence of layer short-circuit (check the primary coil
resistance which is approximately 915Ω±10%). If any abnormal condition is detected,
replace the control unit.
6) Reconnect all leads removed from components during testing.
7) Re-install the outer case (cabinet).
8) Reconnect the power supply cord after the outer case is installed.
9) Run the oven and check all functions.
2. Follow the troubleshooting guide given below, if indicator does not light up after above
check and repairs are finished.
1) Disconnect the power supply cord and then remove outer case.
2) Open the door and block it open.
3) Discharge high voltage capacitor.
4) Disconnect the leads to the primary of the power transformer.
5) Ensure that these leads remain isolated from other components and oven chassis by using insulation tape.
6) After that procedure, re-connect the power supply cord.
7) Follow the troubleshooting guide given below for repair.
STEPS
The rated AC voltage is not present between Pin No. 1 of the 3-pin con-
1
nector (A) and the lower side terminal of the relay RY2.
The rated AC voltage is present at primary side of low voltage trans-
2
former.
8) Disconnect the power supply cord and then remove outer case.
9) Open the door and block it open.
10)Discharge high voltage capacitor.
11)Reconnect all leads removed from components during testing.
12)Re-install the outer case (cabinet).
13)Reconnect the power supply cord after the outer case is installed.
14)Run the oven and check all functions.
OCCURRENCE
8 – 7
a
CAUSE OR CORRECTION
Check supply voltage and oven power cord.
Low voltage transformer or secondary circuit defective.
Check and replace control unit.
d
b
c