WG 6100 (Tempest) Video Collapse Issue

WindDrake

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Hey folks.

So, with my newly ressurrected WG 6100, I've been able to play (finally!) Tempest, but it's got a problem.

In the lower half of the screen (or far right if you were looking at the tube in Horizontal), there's a point we can't move the Y center down to, or the video folds up. It's about two inches from the edge of the screen. Seems like the monitor just runs out of deflection.

I also noticed that I can max the X-Size pot out and still not fill the screen.

Checked everything in the HV cage, all looks well. B+ is a solid 181v, LV section was just recapped and has a LV2000 installed at 26v +/-.

Adjusting the Y Linearity doesn't change the folding, either.

Any ideas on what to check next?
 
Here ya go.

Edit: Reminds me. When you go through the tube to the next level, the vector lines collapse at the shown point in the picture, but they also seem to fall off on the extreme ends of the X Axis (technically Y Axis) as well. Maybe something to do with the fact that I can't max the screen size out?

I was thinking possibly chassis transistors, but the X's chassis set are brand new NTE subs. Rotating X's original transistor pair into the Y doesn't change anything, either.

Deflection board transistors? HV? Yoke?
 

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Have you tried adjusting the pots on the pcb? I don't think it is a monitor problem,I could be wrong though. Just re-read your post, I guess you did try adjusting the size,could be a bad resistor on the deflection board somewhere would be my guess
 
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Have you tried adjusting the pots on the pcb? I don't think it is a monitor problem,I could be wrong though.

I have a similar issue on my major havoc (tempest conversion) with 2 different rebuilt 6100's. Ijust ordered a tempest pot kit (hoping it works for major havoc) I will tackle this myself sometime in the next week.
 
Hit the deflection signals with a scope before leaving work. No flooring on the Y. It's definitely in the deflection somewhere. Bias or a transistor, I'll bet. Will have to poke at it more tommorow.
 
Put the outputs of the board on the scope in X-Y mode and see if it looks good or bad on the scope.

That will help you narrow it down to a board issue or monitor issue. You still could have either.
 
Alright, so, did some more probing with the scope, and thanks for the reminder of X-Y mode, RJ.

Took a look at the board again today, wasn't convinced it was in deflection, as it seems like we may have not moved the Y pot to the right spot to get the screen to fold up again.

So, looking back at deflection output from the game board? Folding.

Looked at the input to the MC1495 multiplier. Not folding. Output? Not folding.

Input to the TL082? Not folding. Out? FOLDING!

So, it's definitely a problem with one of the TL082 gates, either the Opamp itself or a support component. My coworker has these laying around at home, so you'll see an update here monday when we get some to swap in.

We'll get this damned thing running. :)
 
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