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
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 | |
NOTE1: 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.
2)Voltage Check
- Key check point
NO | CHECK POINT |
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1 | IC1 PIN 63,64 | 5VDC ± 5% |
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2 | IC1 PIN 38 | 5V |
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| 0V |
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IC1 PIN 33 or 34
5V
3
0V
T
REMARK
T : 20 ms(50Hz)
T : 250 ns(4MHz)
- Check method |
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NO | MEASURE | WAVE FORM | REMEDY | REMARK | |
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1 | MP1 | DC 5V ± 5% | Replace ZD3, EC1, | No load | |
2 | MP2 | DC 24V ± 20% | Replace | No load | |
NOTE : Each measure point must be measured with GND points.
: The marks of the abovecorrespendig voltage (+5V,+24V) are written on the PCB.
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