Scrolling black bars. Help

[fairway2000]

I have a 25 inch med rez monitor that has a slow scrolling black bar.
It is about 2 inch's tall and has about 8 to 12 black lines scrolling together.
What could this be?

Thanks

[grantspain]

sounds like either an earth or cap issue

[fairway2000]

Any other ideas ? I have 2 new monitors doing it on 2 different games.

Thanks

[Ken Layton]

Pictures please (small file size for those of us like me on dialup) of the problem. Are these brand spanking new monitors or just 'new to you'?

If older monitors, have they been capkitted and had any bad solder joints resoldered? If capkitted, then has the main filter capacitor been replaced?

How is the wiring in the cabinets? Neat and tidy i.e. all 120 volt AC wiring bundled AWAY from any low level video signal and DC power supply wiring?

It could be something as simple as two machines being too close to each other and you're picking up the cabinets power fields---move the machines another foot apart from each other. Could be a fluorescent light ballast in the cabinet causing problems. Temporarily disconnect the light fixture.

[fairway2000]

Thanks for getting back.They are new new.The lines start very faint they get worst.
At power up there is no lines.Starts about 25 min after power up.
Now a little more info.I had one out of the machine sitting on the side of machine and chase was pluged in but not installed in frame.I was not doing it then.Could the case board be to close to the yoke or tube?

Thanks for the help

[SirPeale]

Issues that are not there on startup but come on after time are usually thermal related.  As the components heat up, they expand, and components that may have once had excellent contact with each other may then not, and vice versa.

Start examining the solder side of the circuit board for bad solder joints, and fix as necessary.

[Ken Layton]

If the monitors are brand new then it's very possible for there to be a hairline crack in the circuit boards from rough shipping. What is the brand & model of these monitors?