I have no idea what this is. Any possible identification markings?

I don't recall having talked to you, i reply back to every email and i have been quick to reply to repair emails with a "i can't take any repairs at this time"


the game booting to just garbage is a telltale sign that the game is either A, incapable of writing to video ram or much more likely, is not starting up the z80 at all. Normally this is caused from battery acid damage. You have to fix the battery damage before all else.

https://iankellogg.com/4700-uf-50v-filter-cap.html

just to make this clear. the edge connector IS NOT 0.1"
its 3.96mm or 0.156" you need the split pin contacts not the inline 0.1"

The crimps are discontinued but bob roberts still has them. I dont think anyone else really does except for maybe some obscure surplus site.
Molex split pins bag of 100
http://therealbobroberts.net/conectas.html

Bad rectifier diodes. D7 and D8. use 1N5401 or better.

well you answered your own question. Power supply works, monitor works, game doesn't. Why doesn't game work? because it doesn't have 5V.

you need to figure out why the harness isn't providing 5V to the game.

general rule of thumb. Use a fast blow.

Its rare you want to use a slowblow.
Most games will use fast blow.

The entire point of the battery repair kit I put together fixes exactly the two failures you are talking about. CR2 is one of the most common failures with the battery acid damage chewing up the NVRAM enable pins.

Nothing special between boards for inverting. You have an unknown in the system, do you know the DK board even works?

you mean tube burn in? its a physical thing you can't repair.

not sure i understand what you are saying.

Eitherway it looks like its really out of sync with the signal.

is the remote board plugged in? I'ev seen things like that when the remote board is damaged or missing

you can also just unplug the board. the header is where it comes out from.  but if you rather you can just desolder the resistor R631

so without 30V you aren't going to have 15V, and that is not good. I really dont know what to say right now for what to do next. its clear you have an issue with the 30V rail. This should be fed right off the flyback so if ou have HV then you should have the 30V ac which gets rectified.