Compu Defrost Test; Foil Pattern On The Printed Wiring Board Test - Sharp R-820BK Service Manual

R-820BK
R-820BW
PROCEDURE
LETTER
O

COMPU DEFROST TEST

WARNING : The oven should be fully assembled before following procedure.
(1) Place one cup of water in the center of the turntable tray in the oven cavity.
(2) Close the door, touch the " Compu Defrost " pad once and touch the Number pad "1", and touch the
Number pad 5. And then touch the "START" pad.
(3) The oven is in Compu Defrost cooking condition.
(4) The oven will operate as follows
WEIGHT
0.5lb
(5) If improper operation is indicated, the control unit is probably defective and should be checked.
P

FOIL PATTERN ON THE PRINTED WIRING BOARD 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
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 218Ω ± 10%). If any
abnormal condition is detected, replace
the defective parts.
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.
TEST PROCEDURES
1ST STAGE
LEVEL TIME LEVEL
70% 50sec.
OCCURRENCE
1 Only pattern at "a" is broken.
2 Pattern at "a" and "b" are broken.
COMPONENT TEST
2ND STAGE 3RD STAGE
TIME LEVEL
0% 1min. 50%
CAUSE OR CORRECTION
*Insert jumper wire J1 and solder.
*Insert the coil RCILF2003YAZZ between "c" and "d".
22
4TH STAGE
TIME LEVEL TIME
35sec. 30% 45sec.
c
VRS1
a
FAN
1
d
b
AC
CN - A