First post, by westygw
Hi. This is a real shot in the dark.. but maybe someone can help.
I've got this new CRT I picked up- a Compaq P1210 (HP P1210).
On my DOS PC the image is flawless and stunning.
On my Windows 10 PC, the image has dramatic vertical foldover on the top 1-2" of the display.
This folding is associated with a high pitched whine coming from inside the monitor.
Lowering refresh rate does reduce the foldover and reduce the noise, but it occurs at all resolutions and at any refresh rate.
I can eliminate the folding by lowering the desktop position in the Nvidia settings and then raise the vertical image on the monitor but this also takes 1-2" of the desktop (taskbar) out of bounds of the display.
I've tried multiple modern PC's and switching between native VGA output as well as a DVI-I to VGA converter. Nothing fixes it. Again, it works just fine on my 486 machine all the way up to 1024x768.
The same resolution (1024x768) on my desktop shows the vertical foldover.
After disassembling the monitor I noticed no leaky capacitors or any signs of bulging. Everything is dusty, but in otherwise good shape. The noise isn't coming from the flyback transformer.. but from the circuit board covered in a plastic cover on top of the tube.
Poking the circuit board with a big (nonconductive) stick results in the whine changing pitch and the folding to either increase or decrease in severity.
I'm at a real loss here and nothing seems to alleviate this. If anyone has any shred of a clue what might be causing this, I'd love to hear about it.
I'm uploading a picture of a monitor (just a random one off Google) and highlighting the area where the loud whine comes from.