DAEWOO ELECTRONICS KOC-1B0K0S User Manual download pdf (Page 33)

12. 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: 230 V / Frequency: 50Hz

2) Voltage Check

Key check point

NO CHECK POINT REMARK

1 IC1 PIN 63,64

5VDC ± 5%

IC1 PIN 3 8

T : 20 ms(50Hz)

IC1 PIN 3 3 or 34

T : 250 ns(4MHz)

- Check method

MEASURE

POINT

WAVE FORM REMEDY REMARK

1 MP1 DC 5V ± 5% Replace ZD3, EC1, No load

2 MP2

DC 24V ± 20%

Replace D 20-23, EC6 No load

Terminal Voltage(load) Voltage(no load)

6 ¦¡ 7 AC 17.0V AC 19.9V

8 ¦¡ 9 AC 1.3V AC 1.6V

9 ¦¡ 10 AC 1.3V AC 1.6V

NOTE 1: Secondary side voltage of the low voltage transformer changes in proportion to

fluctuation of power source voltage.

NOTE2: The allowable tolerance of the secondary voltage is within ± 5% of nominal voltage.

: The marks of the abovee correspendig voltage (+5V,+24V) are written on the PCB.

NOTE : Each measure point must be measured with GND points.

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DAEWOO ELECTRONICS KOC-1B0K0S User Manual Page 33