Does Pacman use a rotated CRT? That looks like the electron gun is staying on too long. Maybe a capacitance issue? The longer the gun is on before the spike, the longer the spike. I don't have much experience with arcade machines though. Does Pacman himself look taller than normal?
The shape of the pills found in the screen capture would support your theory...
Yes, Pac-Man uses a CRT rotated 90 degrees so the scan line moves vertically instead of horizontally. I'm sure someone can recommend a tech who knows how to replace these capacitors to get the cathode ray back in sync?
a tangentially relevant article about classic arcade machines soon running out of replacement tubes: http://www.dallasobserver.com/arts/dallas-barcade-owners-stockpiling-cathode-ray-tube-monitors-to-prepare-for-shortage-9301644
It seems like some sort of LCD + FPGA board could inexpensively emulate CRTs, video artifacts and all. The AppleII XScreenSaver is a great example of how close you can get to the CRT look & feel.
All CRT emulators are terrible.
Besides, how's an LCD going to send me on a side quest for capacitors?
An LCD could send you on a side quest for a replacement inverter, or even a capacitor for one.
But I've never seen a great CRT emulation either.
I can’t understand why this post doesn’t have a “zalgo” tag. After all, that’s the explanation.
You want this one.
$17 buys you a lot of capacitors from the usual places.
We already did that, though. I'm guessing this problem is inside the monitor, not the PCB.
If you haven't replaced the caps in the monitor, then that is 100% the problem.
It's either an Electrohome G07 or a Wells Gardner K4900, both very common and easy to find cap kits for:
Yes, but those are much higher quality and better tolerances than the cheap Chinese garbage you get from Aliexpress or wherever.
While you are in there, you should install a high score save kit. It has the bonus feature of stopping me from bugging you to install a high score save kit.
the only 105c pac/ms pac cap kit
likely color bleeding which is from too much brightness or too high color drive/bias pots. also convergence off. very hard to tell from the picture resolution, but i would check those and for sure a cap kit will greatly improve the life of the monitor.