Black gunk on Genesis / MD's CD connector strip

[Timstuff]

I have a Model 2 Sega Genesis, and it has some kind of black epoxy crap all over the edge connector for hooking up with the Sega CD. I read somewhere that this is normal for a Majesco VA4 genesis, since it's basically a Genesis 3 in a Genesis 2 shell, and was not designed for add on compatibility. However, I opened up my genesis and looked at the mother board, and it clearly states "VA1" in white print on the mother board, which is full sized unlike Majesco's system.

I'd imagine that this black gunk is not supposed to be here, since it obviously would prevent the Sega CD from functioning. Just to check my suspicions, I carefully scratched at the the black gunk with a knife, and sure enough there are copper contacts underneath. I can't imagine why Sega wouldn't want me connecting a Sega CD to this particular unit, but it was clearly put on there during manufacturing since the gunk is very neatly and professionally painted on.

I don't really care why Sega covered my edge connector in crap. What I do want to know though, is how should I get rid of it? I suppose sand paper would be one option, although I would be afraid of damaging the contacts in the process. I even tried a pink rubber eraser, but that didn't seem to have any effect. Is there some kind of chemical solution that would get rid of the gunk without hurting the contacts and PCB? Has anyone else had a VA1 Genesis that had this problem?

[17daysolderthannes]

sandpaper is fine, just don't use too rough of a grit. All those contacts do is conduct electricity, they are no different than the plugs that go in a wall socket or anything else. In fact, I have had to sand the pins on some video games before to get them to work, it happens from time to time.

[TmEE]

do you mean this stuff I have scraped off on this pic : http://www.hot.ee/tmeeco/MYSMD2.JPG ?

That is there to prevent corrosion and whatnot... it also acts as 1...2 ohm resistors as its graphite, and as my MCD2 gets its power FROM the MD2, this makes things bad so I scraped it off on some vital pins like 12V output and grounds... while at it I did it for other pins, though on them it does not matter.

[17daysolderthannes]

now that I see that pic I was about to chime in that yeah, thats normal, thats how my Genesis 2 is and works fine with my Sega CD. My Sega CD, on the other hand, is a gear grinding asshole (lol).

[Timstuff]

OK, dandy. Thanks for clearingall that up.

[MN12BIRD]

I have a model 2 and ALL the pins from front to back are completely black. Not burnt looking either. It looks like they just... came black! Its crazy.... whats going on there?

[Ace]

Not all Model 2s are like this, but it always intrigued me. Why did Sega decide to use black contacts on the Sega CD slot on the Genesis 2?

[evildragon]

Late model 1's are also like this. (the ones with CMOS 68K's and not NMOS's..)

[Afcs46]

My MD2 VA4 is just like that... And I don't know its purpose, maybe is just an attempt to prevent the corrosion on those pins.

[TmEE]

I said, its graphite, and its there to avoid corrosion... most of the game controllers, TV remotes etc have it on their contacts.

[evildragon]

You know on this forum most people ignore posts and repost the questions.

[TmEE]

So I can increase my post count by re-answering them :P

[evildragon]

Hmm.. So what about them black gunk? XD

[Timstuff]

My MD2 VA4 is just like that... And I don't know its purpose, maybe is just an attempt to prevent the corrosion on those pins.

I heard that the VA4 is incompatible with the Sega CD anyway, since it basically uses the same hardware as the Genesis 3 / MD3. Can you confirm / refute this?

[ooXxXoo]

All of the official Sega Genesis 2 systems regardless of the revision are compatible with the Sega cd system...Believe it or not, very early revisions of the Genesis 3, can be compatible as well with it if added/modded with an exp port connector....