Switching Regulator Circuit Failure - NEC MultiSync FP1350 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).
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.
Failed
Either (1) +220V, (2) +14.5V, (3) -
15.6V, (4)+8.5V, (5)+5.5V output is
0V.
+80.2V are normal.
No
CONTINUE
1. Make sure that the voltage of between K 1
pin and 3 pin (GND) is approx. 220V.
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.
Passed
Passed
Yes
Check other circuits
Check other circuits
Check the following parts
(1) D6A1, L6A1
(2) D6F1, L6F1, R6F1
(3) D6H1, L6H1, F6H1, ZD6H1
(4) D6G2, R6G1, ZD6G1
(5) D6K1, L6K1, R6K1
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