Daewoo KOC-1B0K6S, Service Manual

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33
12. PRINTED CIRCUIT BOARD
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
2. Voltage Check
- Key check point
- Check method
NOTE
1. Secondary side voltage of the low voltage transformer changes in proportion to fluctuation of power source
voltage.
2. The allowable tolerance of the secondary voltage is within ± 5% of nominal voltage.
NOTE: Each measure point must be measured with GND points.
Terminal
6-7
8-9
9-10
Voltage(olad)
AC 17.0 V
AC 1.3 V
AC 1.3 V
Voltage(no load)
AC 19.9 V
AC 1.6 V
AC 1.6 V
NO CHECK POINT REMARK
1 IC1 PIN 63, 64 5VDC±5%
2 IC1 PIN 38
3 IC1 PIN 33 OR 34
T : 20 ms(50Hz)
T : 250 ns(4MHz)
NO MEASURE POINT WAVE FORM REMEDY REMARK
1 A DC 4.85V Replace EC1 NO LOAD
2 B DC 24V±20% Replace D20-23, EC5 NO LOAD