Printed Circuit Board; Circuit Check Procedure - Daewoo KOR-1A1G0A 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 - 7
NOTE
1. Refer to Circuit 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 ¡ ¾ 5% of normal voltage.
2. Voltage Check
- Key check point
NO CHECK POINT
1 IC 1 PIN 2, 21, 30, 34
2 IC 1 PIN 35
3 IC 1 PIN 31 OR 32
- Check method
NO MEASURE POINT
1 MP1
2 MP2
NOTE
Each measure point must be measured with GND points.
LOAD
AC 12.6
REMARK
-5VDC
WAVE FORM
DC - 5V ¡ ¾ 0.25V
DC - 12V ¡ ¾ 2.0V
32
T : 16.7ms(60Hz)
T : 250 ns(4MHz)
REMEDY
Replace VL1, EC1
Replace EC2, D12,13,14
NO LOAD
AC 14.7V
REMARK
NO LOAD
NO LOAD