Self Test Error - NEC MultiSync FP1370 Service Manual

8. SELF TEST ERROR

Check the self-test mode
NG
IC801 or its ambient circuit failure
OK
Check the self-test H sync output
NG
･Q797 or its ambient circuit failure
･H OSC/DEF circuit failure (see item 6 )
･Digital control circuit failure (see item 12)
OK
Check the clamp pulse output
NG
･IC7A1 or its ambient circuit failure
･IC731, Q734, Q735, Q796 or their ambient circuit failure
･IC791 and their ambient circuit failure
OK
Check the self-test V sync output
NG
･Q793, Q794 or their ambient circuit failure
･V OSC / DEF circuit failure (see item 6 )
･IC8M1, Q831～3 and their ambient circuit on the VIDEO PWB (PWE-567A) failure
OK
Check the self-test video output
NG
OSM circuit failure (see item 4)
OK
IC711 or its ambient circuit failure
Measure the voltage at IC801 pin 14 on the VIDEO PWB (PWE-567A).
The voltage is approx. 0V when self-test.
Measure the pulse at the collector of Q797 on the VIDEO PWB (PWE-567A).
Normally, the frequency of the pulse is approx. 60kHz.
Check the pulse at IC7A1 pin 17 on the VIDEO PWB (PWE-567A).
Normally, the voltage is approx. 5.0Vp-p.
Measure the pulse at IC8M1 pin 15 on the VIDEO PWB(PWE-549A).
Normally, the frequency of the pulse is approx. 120Hz.
Check the pulses 5Vp-p at IC791 pins 13(R), 15(G), 17(B) and
12(Blanking) on the VIDEO PWB (PWE-567A).
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