180c contrast drifting issue - inverter board caps?

3lectr1c

Active Tinkerer
May 15, 2022
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I picked up a 180c a few months ago. It worked but really needed the screen recapped, so I did that and the picture quality looks better now (no more artifact issues), but it’s got another problem.
When I first turn it on, the screen looks perfect, but it will slowly down the contrast until white objects look dark gray, and readability goes down a lot.
B0256787-5510-469C-B65F-E8DCA691D56F.jpeg

Does this mean it’s time to recap the display inverter board, or is it a different problem? This is an active matrix display, and it has no control for the contrast, neither hardware or in software.

The inverter board has 2 small through-hole electrolytics, and they both look fine. Could 2 small caps really cause this big of an issue?

When it's starting to drift and go dark, it will "flash" back to normal for a second a handful of times until it eventually just stays dark.

Thanks!
3lectr1c
 

3lectr1c

Active Tinkerer
May 15, 2022
629
294
63
the United States
www.macdat.net
Update for anyone viewing this with the same issue - it's a voltage issue. Adjusting the front voltage potentiometers somewhat fixes it, although I haven't been able to get it perfect, but I've gotten it so that it does this when it's first been started up and then goes back to normal after about a minute.