Oh god, what have I done.

[FireSlash]

Ok,, possible cause found. Bot the 6820s, and U6 as well, have some weird black crap infesting the pins. Looks similar to what I saw on the fuse holders. I've scrubbed the pins profusely with contact cleaner, very little has come off. Not sure if there's anything to be done short of replacing the affected chips. Any idea what this crap is, and what causes it?

edit: CPU is fine, but U2 and U6 are both affected. I've pulled the 6820s, cleaned, and put them back in. waiting for the cleaner to fully dry before I know more. Sockets are NOT the closed frame type.

 

[tomdotcom]

haha all pins have that black dust crap..its from coils stops, metal parts, electronics, combination of a bunch of things...

 

[FireSlash]

Cleaned U2/u6 and the 6820s. Seems to be normal for now, but I couldn't even come close to getting all of that crap off. I'll order new chips in a few days. Though I suppose I'll have to jumper the roms now :\

 

[DillonFoulds]

I took a burnisher to all my IC legs when I pulled the boards and re-soldered/fluxed the connectors. *shrugs* I guess an ounce of prevention? You should be able to get burnishers from any local electronic store, or from Pinball Life.

Also;

... being pretty much as common as finding a joystick on an arcade machine...

You haven't been to any "arcades" up here in Alberta then. Golden Tees and Big Buck Hunters, and if you're VERY lucky a pin, but it's usually an UltraPin

 

[Lindsey]

Cleaned U2/u6 and the 6820s. Seems to be normal for now, but I couldn't even come close to getting all of that crap off. I'll order new chips in a few days. Though I suppose I'll have to jumper the roms now :\

Why are you planning to order chips? Have you actually done any troubleshooting?

The easiest way to work on Bally MPUs is going to be out of the machine with Leon's test ROM. If that's not an option and you suspect a PIA problem you can swap the 6820/21 chips and see if the problem changes... or the MPU fails to boot.

Don't just throw parts at the thing. That's no way to fix anything.

Just my $.02

 

[Tombo]

OK guys. Agree to disagree.

-Tom

 

[Lindsey]

OK guys. Agree to disagree.

-Tom

Dude... you're about a week late on this one.

 

[FireSlash]

Why are you planning to order chips? Have you actually done any troubleshooting?

The easiest way to work on Bally MPUs is going to be out of the machine with Leon's test ROM. If that's not an option and you suspect a PIA problem you can swap the 6820/21 chips and see if the problem changes... or the MPU fails to boot.

Don't just throw parts at the thing. That's no way to fix anything.

Just my $.02

If the oxidation isn't a problem now, it will be later. Same thing happened with the fuse holders. I already know the 6820s aren't at fault since I swapped them during re-installation. But they're cheap enough that I don't mind lumping a couple in the next order to prevent issues down the line.

 

[Lindsey]

If the oxidation isn't a problem now, it will be later.

True, but later could be 10 years from now.

I already know the 6820s aren't at fault since I swapped them during re-installation. But they're cheap enough that I don't mind lumping a couple in the next order to prevent issues down the line.

Fair enough. It's easy to justify this kind of stuff in a one-off capacity. If you're restoring a lot of games you can burn through a lot of money replacing working parts.

I'll stand by this statement:

Don't just throw parts at the thing. That's no way to fix anything.

EDIT: You should replace the sockets while you're at it.