Afterburner

[Lurch666]

I'm looking at a sega afterburner PCB that's either booting to a blank screen or garbage.
I've burned the test roms that replace the 11107 and 11108 eproms but it's made no difference.

One thing is the data and address lines on both the main 68000 CPU and the CPU eproms (11107 and 11108 again) look off.

On the CPU all the address lines have low signals while all the data lines have high signals. But there's not any apparent activity on either and after a few seconds they both stop showing any activity at all.
On the CPU roms it's the same except it's the address lines that have normal high signals and the data signals are low.

68000 address lines:


68000 data lines:

CPU roms address lines:

CPU roms data lines:


I'm guessing that's not normal.

 

[Lurch666]

So tracing signals and I noticed some of the enable signals which were off came from the GAL at IC109.
It was in a socket and pulling it I noticed pin 10 was bent out of the socket. Sorted that and it ran the test roms with all OK.
Put the game roms back in and game is now booting.
Colours are off and not sure if the initial issue of graphics glitches are still there since until I sort the colours it's hard to tell.
I probably just have the RGB in the wrong order.

EDIT:Green and blue were swapped. All looking good now-can't see any obvious graphic glitches.

 

[Jacmar]

You still got the weird low signals?

 

[Lurch666]

Just checked.
Now while the screen is black for the second or so before the game shows there's no signals on data or address lines.
Once the game starts normal data and address signals appear where before there was the janky signals as soon as power was applied which disappeared after a second or so.