Osc / Def Circuit Failure - NEC MultiSync FP1370 Service Manual

7. V OSC / DEF CIRCUIT FAILURE
Check +15V/-15V line.
NG
･CN-K wire failure.
･Check SW REG. (see item 13)
OK
Check the sawtooth wave at IC421 pin 8 on the DEF PWB (PWE-624).
NG
Check the sawtooth wave at CN-DSB pin 11 on the DEF PWB (PWE-624).
NG
Check the vertical input trigger.
OK
Check the sawtooth wave at IC511 pin 12.
OK
･IC501 failure.
･Digital control circuit failure (see item 12)
OK
･IC401 or its ambient circuit failure .
･V DY failure.
Measure the voltage at CN-K pins K2 and K4 on the DEF PWB (PWE-624)
Pin K2 voltage is approx. 14.5V. Pin K4 voltage is approx. -15.6V.
OK
IC421 or its ambient circuit failure.
NG
Check the unstable picture (see item 3-2)
NG
IC511 or its ambient circuit failure.
Check sync pulse (VD) at CN-DSB pin 6 on the DEF PWB
(PWE-624)
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