Printed Circuit Board; Circuit Check Procedure - Daewoo KOR664BWTAE013AB00 Service Manual

PRINTED CIRCUIT BOARD

1. CIRCUIT CHECK PROCEDURE

1. Low voltage transformer check
The low voltage transformer is located on the P.C.B.
Measuring condition: Input voltage: 120V / Frequency: 60Hz
Terminal Voltage
(4,5)-6 or (7,8)-6
NOTE
1. Refer to Circuit Diagram.
2. Secondary side voltage of the low voltage transformer changes in proportion to fluctuation of power source
voltage.
3. The allowable tolerance of the secondary voltage is within ± 5% of nominal voltage.
2. Voltage Check
- Key check point
NO CHECK POINT
1 IC1 PIN 5
2 IC1 PIN 8
IC 1 PIN 19 OR PIN 20
3
- Check method
NO MEASURE POINT
1 MP1
2 MP2
NOTE
Each measure point must be measured with GND points.
LOAD
DC 11V
5VDC
5V
0V
5V
0V
WAVE FORM
DC 5V±0.25V Replace Q8, R28, ZD3, C2, EC1
DC 11V±3.0V
24
REMARK
T : 16.67ms(60Hz)
T : 250 ns(4MHz)
REMEDY
Replace EC3, D11, D12, D13
NO LOAD
AC 30V
REMARK
NO LOAD
NO LOAD