NEC MultiSync FP1370, Service Manual

Page: 112 / 286

7-24
8. SELF TEST ERROR
Measure the voltage at IC801 pin 14 on the VIDEO PWB (PWE-567A).
The voltage is approx. 0V when self-test.
NG
OK
Measure the pulse at the collector of Q797 on the VIDEO PWB (PWE-567A).
Normally, the frequency of the pulse is approx. 60kHz.
NG
OK
Check the pulse at IC7A1 pin 17 on the VIDEO PWB (PWE-567A).
Normally, the voltage is approx. 5.0Vp-p.
NG
OK
Measure the pulse at IC8M1 pin 15 on the VIDEO PWB(PWE-549A).
Normally, the frequency of the pulse is approx. 120Hz.
NG
OK
Check the pulses 5Vp-p at IC791 pins 13(R), 15(G), 17(B) and
12(Blanking) on the VIDEO PWB (PWE-567A).
NG
OK
Check the self-test mode
IC801 or its ambient circuit failure
Check the self-test H sync output
･
Q797 or its ambient circuit failure
･
H OSC/DEF circuit failure (see item 6 )
･
Digital control circuit failure (see item 12)
Check the clamp pulse output
･
IC7A1 or its ambient circuit failure
･
IC731, Q734, Q735, Q796 or their ambient circuit failure
･
IC791 and their ambient circuit failure
Check the self-test V sync output
･
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
Check the self-test video output
OSM circuit failure (see item 4)
IC711 or its ambient circuit failure