On Screen Manager (Osm) Failure - NEC MultiSync FP1370 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). when EXIT, 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-624))
Check the pulse 5Vp-p at IC791 pin 19 on the VIDEO PWB (PWE-567A).
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