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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%
2
IC1 PIN 3 8
T : 20 ms(50Hz)
3
IC1 PIN 3 3 or 34
T : 250 ns(4MHz)
- Check method
NO
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.
5V
0V
T
5V
0V
T
NOTE : Each measure point must be measured with GND points.