Printed Circuit Board; Circuit Check Procedure - Daewoo KOG-37BG0S 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: 230V / Frequency: 50Hz
Terminal Voltage
4-7
NOTE
1. Refer to Ciruit Diagram (point 4).
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
NO CHECK POINT
1 IC1 PIN 2, 21, 30, 34
2 IC1 PIN 35
3 IC1 PIN 31 OR 32
- Key check point
- Check method
NO MEASURE POINT
1 MP1
2 MP2
NOTE
Each measure point must be measured with GND points.
LOAD
AC 12.6 V
-5VDC
WAVE FORM
DC -5V±0.25V
DC -12V±0.2V Replace EC2, D12,13,14
26
REMARK
T : 20ms(50Hz)
T : 250 ns(4MHz)
REMEDY
Replace VL1, EC1
NO LOAD
AC 14.7 V
REMARK
NO LOAD
NO LOAD