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180c contrast drifting issue - inverter board caps?

3lectr1cPPC

Well-known member
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 (artifacting is gone - I had a thread on it a few months back), 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?

Edit: 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
 
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Byrd

Well-known member
Try a recap, but I'd experiment first with different room temps - thinking it might be an LCD polarizer issue. Try using the Mac in a very cold room and see if you can extend the delay, alternately warm up the PowerBook and test the other way.
 

3lectr1cPPC

Well-known member
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.
I'll go ahead and give that a try but this behavior would at least to me suggest otherwise. It has been steadily getting worse since I got it, but I'll go give it a go in the 70+ degree outdoors.

Edit: Just tried it but it hasn't been off long enough for it to "cool off" again I guess, because it had the issue immediately. It's also not that much warning outside than inside at the moment so it probably wouldn't have changed much.
 
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