SW trouble

From: Biff <boffbiff_at_hotmail.com>
Date: Sat May 12 2001 - 19:53:21 EDT

Still unable to find the fault on this W/G monitor.

Symptoms:

Colour guns are working (as far as I can tell) it looks like only horizontal
portions of the graphics are working, could it be a problem with the Y side
of the amp?
Similar mess to that put across your TV when car goes by with duff
suppressor but not rolling. The images displayed are roughly in proportion
to what should be displayed, but only horizontal segments.

What little is being displayed seems to be biased to the right?
The red led on the monitor board goes on for a short time and then go's out,
is this usual?
There is a slight rainbow affect to the whole screen?
Horrible high frequency clicking coming from the tube (valve).
With nothing plugged into the monitor board i.e transistors, neck PCB and HV
box, the red indicator, mentioned earlier, stays on?

What i know:

Audio self test reports no problems (16 high pitch beeps)
There are no transistors S/C or O/C. All diodes appear to be ok on diode
test on al pcb's.
As per a helpful tip from Steven Gregory (thanks m8) HV side is kicking out
180v on pin 5, P900.
Audio board operates ok along with general game i.e. coining up and initial
game sequence.

I have looked through some of the archives and i will be looking into them
further.

In the absence of a scope, could someone let me know correct voltages at
certain crucial points to help me fault find the PCB.

Sorry to keep bugging you.

Thanks

Biff

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Received on Sat May 12 20:07:04 2001

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