What Alltek did is a good idea and is often used for protection from errant input power. In blowing - it may have saved a lot of valuable IC's.

Based on their online description:
"Our board also has an over-voltage protection circuit. This feature protects your game from voltage spikes that can damage an MPU board. If the Ultimate MPU board sees a voltage spike, it goes into protection mode. When you're ready to reset the circuit, all you have to do is cycle the game off and on."

Cycle power to reset means the board has a solid state fuse, you don't change this fuse.
Regardless - it does look like that one is either open or being retriggered. Since TP1 = 5V, the OVP could be malfunctioning and retriggering each time it is turned back on.

They did this the right way.
MC3423 was a very popular part for over voltage protection. Too bad it's now obsolete. There are alternates out there but not with the same pin out.

Vtrip = 2.6V(1 + 6200/5100) = 5.76V.

But since his board works in a different machine - it seems to be machine dependent, not board dependent. The machine that does not work properly may be experiencing spikes on the +5V inputs that are quick enough to trigger the OVP.

The fuse part in the photo - I don't recognize the part marking. But with the "V" and inverted "V" on the device - it's a polyswitch resettable fuse or "PTC". Probably one of a thousand variations made by Littelfuse, maybe their RUEF series.

One thing I can see is the "090" means it is a 0.9 amp part, not 1.1 amp.

So sound board gets its power from the CPU board.
It could be overloading the 0.9 amp fuse. Wouldn't hurt to recap it - stable power always helps.