Digital Control Circuit Failure; Digital Control Error - NEC MultiSync FP1370 Service Manual

12. DIGITAL CONTROL CIRCUIT FAILURE

12-1. Digital control error

Check +8.5V line
NG
Check SW REG (see item 13)
OK
Check +5V line
NG
IC8G1 failure.
OK
Check Reset circuit
NG
IC8G1, C814, IC801 failure
OK
Check the waveform at IC801 pins 41 and 42
NG
X801, IC801 failure
OK
Check Sync signals
NG
Sync interface circuit failure (see item 3)
OK
IC801 failure
Check the voltage at CN-P pin 6 on the VIDEO PWB(PWE-567A).
Check the voltage at IC8G1 pin 2 on the VIDEO PWB(PWE-567A).
When +5V is supplied to the circuit, IC801 pin 35 should vary from LOW level
(approx. 0V ) to HIGH level ( approx. 5V ).
Check the pulse 5Vpp at IC801 pin 4 (H sync), IC801 pin 36 (VD), IC801 pin 59
(H polarity) and IC801 pin 58 (V polarity) on the VIDEO PWB (PWE-567A).
2Vpp 10MHz sine wave
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