bad carts or console issue?

[jjh76]

I recently bought a model 1601 gensis with the "high definition graphics" label above the cartidge port. I only have a few games for it yet, but most of them work. The two that don't work are Phanom 2040 and MIck & Mack Global Gladiators. With both of these games the Sega license message shows up, but then it freezes on a black screen. Since the other games I have work, I thought that maybe these two carts were bad.

 

However, I just bought the Sonic games. All four of them run normally by themselves. Putting 1 or 2 in Sonic and Knuckles also works like it should. Putting Sonic 3 in I get this:

 

I can start a new game and the opening cut scene run, but with a few graphics glitches. When it gets to the point where Knuckles takes the chaos emeralds, the system resets.

 

Is this a problem with the carts, or do I maybe have a bad ram chip or something in the console itself?

[spacecadet]

It sounds more to me like it might be oxidation on the contacts, probably of those few carts. Try cleaning the contacts, and do the same on the slot in the console (and the slot in Sonic and Knuckles). Oxidation can lead to this kind of intermittent problem, where there's just enough on the console that some carts won't work if they too have just enough oxidation on those same pads.

 

If some carts work, and none of these are doing anything too special from what I know, then I doubt it's anything really wrong with the console.

[keepdreamin]

The sega license screen, then to black is a common symptom of a poor connection. For troublesome games, I'll usually fully seat the cart, then pull it back up just a tiny amount and try to restart.

[jjh76]

The two with the black screen I've tried pulling up slightly or putting them at slight angles, but still can't get anything to happen.

 

Whenever I buy a cartridge based game I always clean the pins with 90% isopropyl alcohol on a cotton swab, usually do this multiple times until the swabs stay white. With sonic 3 and knuckles, further attempts as cleaning the sonic 3 cart have caused slight changes in the way the graphics glitch out, but it's still unplayable even though sonic 3 runs fine by itself.

 

As for cleaning the cartridge ports, both on the console and on the knuckle cart, following some suggestions I've read elsewhere I've tried using a cut out a piece of cardboard or wrapping a credit card in printer paper, but I can't tell if either method has done any good

[+-^CrossBow^-]

interesting...my copy of Sonic 3 was doing something similar though the graphical glitches weren't as bad. I'm still not sure it is fully resolved, but I was able to pretty much kill the issue by applying some fresh solder and heat to the main 68K CPU pins. Redid all the ones on the bottom of the PCB and then redid what I was able to reach on the top of the pcb as I discovered some of the traces didn't go all the way through the vias as they should.

 

The other possibility could be a flaky ram chip, but I also think a thorough examination of the cart slot on the genesis itself is needed. Make sure no pins are bent back further than others or look to be folded in..etc.

[jjh76]

Cart slot seems fine, nothing looks bent, same with the slot on the knuckles cart. Tried re-flowing the solder on the 68k but no change.

[spacecadet]

Alcohol may not be enough, and you can't really see oxidation visually. Get yourself a can of Deoxit D5 and try that. Alcohol cleans but doesn't really deoxidize. You need something made specifically for that.

[jjh76]

Went looking through a few stores today, couldn't find any that sell Deoxit. Is there an alternate brand I should look for?

 

Trying to get it to work again today, discovered that it erased my game saves from the sonic 3 cart. Do the batteries used in these carts ever leak and eat away at the rom pins? The guy at the local retro game shop has the special screwdriver, think I'll take them over tomorrow and ask him to open them up so I can get a look at the pcbs

[+-^CrossBow^-]

Went looking through a few stores today, couldn't find any that sell Deoxit. Is there an alternate brand I should look for?

 

Trying to get it to work again today, discovered that it erased my game saves from the sonic 3 cart. Do the batteries used in these carts ever leak and eat away at the rom pins? The guy at the local retro game shop has the special screwdriver, think I'll take them over tomorrow and ask him to open them up so I can get a look at the pcbs

 

I don't believe Sonic 3 uses a battery. It actually is supposed to use non-volatile flash to store the game saves. If they are getting erased, that is due to a connection issue between the cart and the system. Kinda like turning the power off in the middle of a firmware update corruption the update...etc. My sonic 3 has done that a few times and it was quite annoying when I had issues with the graphical glitches.

[jjh76]

Ok, they guys at the game shop opened the games and really scrubbed the pins. Still didn't work.

 

We then tried their copy of s3 with with my copy of s&k, didn't work. Then we tried their copy of s&k with their copy of s3 and that worked. Then their copy of s&k with my copy of s3 and that worked. Finally we tried my copies of both again and this time it worked.

 

Got home and they had stopped working again.

 

After fooling around with it a bit I found that if I pushed back on the top of the s3 cart before turning it on it would work, so even though the pins don't look bent a few of them aren't connecting when the carts in straight. Then I had an idea. I have some strips of 1/16" self sticking rubber foam laying about. Cutting two pieces off this I put one against the back of the s&k cart and and another on the front side of the s&k cart's slot. Together, these two pieces push the s3 cart forward just enough to keep pins connected without having to push the top of the cart back each time I put it in.

Edited July 9, 2017 by jjh76