Hippy Beads on top 1/2 of WG 19K7901

[_) (V) (-)]

Hey guys,
I've got a freaky problem with this 1991 Tatio Special Criminal Investigation cabinet I picked up. Seems to function fine, but has some artifacts in the top 1/2 of the display.

The artifacts can best be described and similar to the 'jailbars' problem I've seem posted some other posts. However, it does not display all the time. Only some screens seem to be affected. Sometimes it flashes and changes colors. This activity seems to be related to the goings on in other parts of the image.

Here is what I think are the specs:
Wells Gargner Model no 19K7901
(See photo)

[_) (V) (-)]

I've done a visual and the caps 'look' OK. None seem bulged or leaking.
I've reseated connectors and twiddled a few knobs, being careful to put them back where they were.

Another thing I've noticed is the image seems to be too wide to fit the screen.
I'm losing about an inch on either side when centered. If you know this games screen, I can not get the damage or distance bars to both display on the screen.

Look at the screen display photo. Notice how the stripes appear under some parts of the image (The lettering in the start message) and over others? As I mentioned before, some parts of the game are more affected than others.
Some screens have no problem.

Almost makes me think it could be a faulty chip on the program board but I don't know chit from chinola here. I would really like to hear what the house physicians have to say on the matter.

Any assistance would be greatly appreciated!
Thanks
_)

[bluevolume]

I'm just a newbie when it comes to monitors, but it looks to me like there is a problem with the memory on the PCB.  Looking at the location and uniformity of the lines, I don't think its the monitor.

But once again, I could very well be wrong.  What do the authorities here think?

[Ken Layton]

Looks like a gameboard problem.

[Kevin Mullins]

Yeah, I agree....... the lines look to be a game pcb issue.

Now the sizing problem may be a monitor width adjustment issue.

[_) (V) (-)]

Just as I feared.

How should I go about tracking down something like this?
I've tried reseating all the 'socketed' chips on the two boards, no change.

I've got a manual but it doesn't go into the board stages or chip functions.