Daewoo KOC-154K Service Manual download pdf (Page 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: 220~240V / 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(load)

AC 17.0 V

AC 1.3 V

Voltage(no load)

AC 19.9 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 5V±5% Replace ZD2, EC1 NO LOAD

2 B DC 24V±20% Replace D23-26, EC4 NO LOAD

1 2 ... 28 29 30 31 32 33 34 35 36 37 38 39 40

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Daewoo KOC-154K Service Manual Page 33