Switching Regulator Circuit Failure - NEC MultiSync FP1370 Service Manual

13. SWITCHING REGULATOR CIRCUIT FAILURE

Check the output voltages
Failed
1. Turn off the power switch and wait 1 minute.
2. Disconnect CN-K & P & PM & CR & PS from SW/HV PWB(PWE-571).
Disconnect CN-D from SW/HV PWB(PWE-571).
3. Short Q673 emitter and Q673 corrector on the SW/HV PWB(PWE-571)
4. Add dummy resistor (2.2KΩ,±10%,40W) in parallel with R6A1.
5. Add dummy resistor (82Ω,±10%,2W) in parallel with C6G2.
6. Turn on the power switch and check the output voltages again.
CONTINUE
1. Make sure that the voltage of between K 1 pin
and 3 pin (GND) is approx. 230V.
2. Make sure that the voltage of between P 3 pin
and 5 pin (GND) is approx. 80.2V.
3. Make sure that the voltage of between K 2 pin
and 3 pin (GND) is approx. +14.5V.
4. Make sure that the voltage of between P 6 pin
and 5 pin (GND) is approx. 8.5V.
5. Make sure that the voltage of between K 4 pin
and 3 pin (GND) is approx. -15.6V.
6. Make sure that the voltage of between CR 1 pin
and 2 pin (floating GND) is approx. 5.5V.
7. Make sure that the voltage of between D 1 pin
and 2 pin (GND) is approx. 20.0V.
8. Make sure that the voltage of between D 3 pin
and 2 pin (GND) is approx. -20.0V.
Check other circuits
Passed
7-30