68kMLA Classic Interface
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| Click here to select a new forum. | | Macintosh Portrait Display squeal | Posted by: TrueNorthStrong on 2026-08-23 11:34:21
Hi folks,
Working on clearing some backlogged stuff, and I'm revisiting my Portrait Display.
The last work that was done about two years ago was a recap. Not full, just the main board. Things like the neck board and various smaller breakouts still have the original caps.
I had it out to perform some image adjustments to get it back into shape, and after a bit of time (20 minutes are so) the display turns off, fan powers off, and there is a pronounced squeal coming from it. This isn't usual CRT whine or coil whine.
If the power is turned off for some time, it will "cool off" and turn back on, but the problem comes back. Time to return depends on how long it's been turned off for.
I've rechecked the caps, and all appear to be installed correctly. To that point, nothing's popped inside, no visible damage to any components.
It certainly seems power related, as it makes a sound as if part or all of the monitor powers off when the squealing starts.
I assume there's something to be checked in regards to the voltages the power supply is putting out, maybe something is out of spec and it sags enough to cause the power supply to go unstable. But, figured I'd post here if anyone has specific advice before I go about poking around blindly.
Thanks! | | 1 |
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