Pole Position "wavy" over time...

linx310

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Been going through this Pole Position and rebuilding it. Did a cap kit, HOT, and new fly back and brought the original monitor back to life.

When I first power the game on everything is fine for the first few minutes. But after a period of time the display starts to get "wavy". After about 10-15 minutes the display is going crazy.

Here is a video spliced together of what is happening.

https://www.dropbox.com/s/m0comyimffkkwri/ppmalfun.wmv?dl=0

Does this seem like a power supply filter cap issue?
 
What kind of monitor?

A couple of ideas... B+ could be too high. After a rebuild you generally need to let the monitor run for 20-30 minutes before adjusting the B+.

Horizontal sync pot is flaky/bad?

I'm not a monitor expert. I just remember hearing discussion of a similar problem on a podcast and in that particular case it was that the B+ was too high.
 
Adjusting the B+ voltage may have fixed it. After 30 mins it was reading 130 v. Spec says it should be 123. Turned it down and it fixed it.
 
Adjusting the B+ voltage may have fixed it. After 30 mins it was reading 130 v. Spec says it should be 123. Turned it down and it fixed it.

Sweet. The picture looked really good at first in your video. The fact that it started waving a short while later and got progressively worse was a good indicator that the B+ was too high. I've seen pots go bad in real time, though, that resulted in similar behavior.

Let it run for a while and recheck the B+ a few times to make sure it doesn't drift.
 
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