Dead Street Fighter 2

I guess I didn't mention that I own 50% of a Street Fighter 2? We got it cheap from a guy who wasn't very good at fixing pinball machines. It seemed whenever he got a new game and started restoring it, problems were near. He often ended up with a couple of fried components and a big question mark, and sold the machine.

It's been a couple of years since we bought it, and we haven't looked much at it since then. Whenever we tried to boot it, there was only garbage on the display, and the boot process halted. Someone suggested changing the display chip. I don't even remember what it was called anymore (U9??), but that didn't help.

Fast forward to today, and we have discovered that all the LEDs inside the backbox are lit. They don't blink, they just stay on.

My friends found that the +5v was just above 4, so they adjusted it, but they quickly realized that the real problem was somewhere on the CPU board.

What happened next was quite frankly a bit of a mystery to me, as I've learnt the basic electronics I know from pinball machines. They were using an oscilloscope to check the pulses from the crystal.. or the CPU.. or something. But it didn't look right, I understood that much.

My more electronics proficient friends suspect that the fault lies somewhere in this region of the schematics.

...or this section of the board.

I don't know what to believe, as this is a bit above me. My friend and part-owner has taken the board home for further checking. With a bit of luck, he'll have it up and running again in some days.