On Screen Manager (Osm) Failure - NEC MultiSync FP1350 Service Manual

4. ON SCREEN MANAGER (OSM) FAILURE

Check the OSM signals output
OK
• IC711 failure
NG
Check the H sync input
• Q791 or its ambient circuit failure
NG
• CN-AF failure
• Q5E1 or its ambient circuit failure
OK
Check the V sync input
NG
IC7A1, Q793, Q794, Q795, Q7A2 or their ambient circuit failure.
OK
• IC791 and its ambient circuit failure
• Digital control circuit failure (see item 12)
Check the pulses 5Vp-p at IC791 pins 13(R), 15(G), 17(B) and
12(blanking) on the VIDEO PWB (PWE-567A).
CONTROL or PROCEED SW is pressed.
Check the pulse 5Vp-p at IC791 pin 18 on the VIDEO PWB (PWE-567A).
(on the DEF PWB(PWE-568))
Check the pulse 5Vp-p at IC791 pin 19 on the VIDEO PWB (PWE-567A).
7-10
When EXIT,