BattleZone Mini Video Problem

Arcadenut

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If you look at the attached picture, you can see that the text starts to slant upwards the further down the screen it gets.

The monitor has been rebuilt and Big Blue has been replaced.

Any one seen this issue or have a clue where I should start looking?

Any help would be greatly appreciated!

Thanks!
 

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Purity rings only exist on color raster monitors. This is a B&W vector monitor. On the neck should be some rings with tabs, but they are just for centering the image.

In any case, this looks like a PCB issue to me. Specifically, in the analog section of the vector generator output. Likely in the Y-axis.
 
Ok, recapped the PCB and no changes (what I expected).

It appears to be in the YBIP section, not sure if it's the POT or another component. If I adjust the POT Clockwise, the skewing gets worse.

I adjust the pot as far Counter clockwise as I can, and it's still skewed (like in the picture).

Looking at the schematic, It looks like it could be R72 or R73 maybe?
 
If you have change when adjusting the pot, then it's probably not that.

At this point I would check the +- 15 volts.

Without a scope on it to see what it's doing exactly, I would suspect one of the following chips.

D9, D10, E10
D10, and E10 are the cheapest to replace, D10 being the easiest.
 
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