Hyper Olympic / Track and Field pcb revisited

This is the Hyper Olympic board I've mentioned in previous posts, I've already replaced most of the sockets and almost all the eproms as all but four were missing when I got it. It ran the test rom but with colour problems so I knew it was very close to working. The reason I kept putting this one off is I had no way of testing all the custom chips.

This is where I left off and sure enough still the same.

First to fix the colour issue.

This was caused by a bad fujitsu ttl on the bottom pcb (74LS157). You'll also notice I've setup my TV properly since last time as it's 4:3 and the AV1 doesn't stay on the screen now. :)

The test rom always flagged the NVRAM as bad, I just assumed this was due to the missing battery. I removed the battery when I first got the board as it had started to leak. I also didn't think a problem with the NVRAM would stop the game from running but might as well sort it out now.

I fitted a battery just to see if the NVRAM test would pass but it still failed hmm. On closer inspection the tiny blob of battery acid had taken out a trace and worked it's way into pin 24 of the NVRAM (6116).

It's not often you see the markings scraped off ram ics.

 A tiny bit of kynar wire and some solder mask to cover it up.

or should I say solder mast.

I tried the board without the replacement 6116 in it's socket just to see if I still had a screen of zeroes and sure enough it wasn't just the trace. Very strange that konami would make it so the game wouldn't run if the nvram is bad since it's only used for scores.

Repair complete.