Service manual

18
R-520KS
TEST PROCEDURES
PROCEDURE
LETTER
COMPONENT TEST
To protect the electronic circuits, this model is provided with a fine foil pattern added to the primary on the
PWB, this foil pattern acts as a fuse.
1. Foil pattern check and repairs.
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) Follow the troubleshooting guide given below for repair.
STEPS OCCURRENCE CAUSE OR CORRECTION
1 Only pattern at "a" is broken. *Insert jumper wire J1 and solder.
2 Pattern at "a" and "b" are broken. *Insert the coil RCILF2003YAZZ between "c" and "d".
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 563ý ±
10%). If any abnormal condition is detected,
replace the control unit assembly.
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.
L FOIL PATTERN ON THE PRINTED WIRING BOARD TEST
RY2
VRS1
L1
J1
a
b
cd
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 OCCURRENCE CAUSE OR CORRECTION
The rated AC voltage is not present between
1 the normal open terminal of the relay RY1 and Check supply voltage and oven power cord.
the normal open terminal of the relay RY2.
2
The rated AC voltage is present at primary side Low voltage transformer or secondary circuit defective.
of low voltage transformer. Check and replace control unit assembly.
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.
(5) The oven will operate for the first 16 seconds, without generating microwave energy.