Fault finding SNES cartridge pcb

[lev11]

Hi, I've recently bought a 2nd hand SNES game, Micro Machines PAL, which doesn't work. Just get a black screen when turning on the SNES. This is unusual as I've had quite a few 2nd hand games and all to date work, though some have needed a bit of cleaning.

Cleaned the contacts as they did look a bit grubby to begin with, but certainly not the worst I've seen though.
Tried in two PAL SNESs which both have been cleaned recently and play 10s of other games flawlessly.

Images of the PCB here:



The only sign of a possible issue is slightly exposed trace on two of the pins that go direct to the mask ROM, pin's 15 & 16. But when tested with a multimeter I've got continuity between each cartridge pin and the associated pin on the mask ROM, and no shorts between the adjacent pins.



Searching for fixing this kind of thing just brings up loads of info about not blowing into it and just cleaning the pins.

Would an exposed track cause a game to not work, some kind of interference as they are so close together, or reason that it only fails when the cartridge is powered up?

Other than buying a replacement donor PCB and swapping the rom I wondering whether I should just cut the 2 tracks and fit a short length of wire between the cartridge pin and the mask rom pin.

[tribal_war]

The two exposed traces shouldn't affect the operation of the cartridge at all unless it is being grounded on something. The more likely culprit would be the mask rom or the CIC IC on the PCB. You can try and swap with a donor PCB but if it is the mask rom it's still not going to work.

You could replace it with a EPROM, not sure which would be compatible or whether you'd have to do any extra wiring to get it working.

Is Micro Machines an expensive game? If not, I'd just try and pick up another one.

[lev11]

It's not mega expensive but not one of the cheap ones either, currently ~£14 on ebay.uk.

The exposed bit of the traces is exactly where the front cover makes contact and there's even a green mark on the cover, so either it's worn in time with movement or the lacquer was still wet when the cartridge was assembled and it's since pulled off.

I've checked this site http://jensma.de/snes/ and there's a few cheaper equivalents to try a ROM/CIC swap.

Think I'll try reflowing the joints first though.

[hellbelly]

How's the end of the cap look, is it flat or bulging?