Sonic and Knuckles...graphic corruption, resets, and lockups
So while testing out a couple of Traco DC-DC buck converters in my genesis last night I discovered that apparently my Sonic and Knuckles cart doesn't like to play with Sonic 3 locked onto.
Both games will play fine by themselves, but when I attach Sonic 3 to Sonic and Knuckles, this is what tends to happen:
Starting up a game of Sonic 3 while attached to S&K will cause the game to lockup within about 60sec of starting. Doesn't matter what character you choose and it usually corrupts the save file requiring I delete it.
If it doesn't do that, then it will exhibit graphic corruption. Usually it will generate a series of missing sprite graphics as uniform squares on the screen. Doesn't always do this and the corruption will change and isn't ever the same.
If left on long enough trying to get through this, it will eventually start to reset the game back to the Sega logo and back to title screen. Within a min or so of this, the game will reset after displaying the Sega logo and continue.
So I thought the DC - DC buck converters might be the issue, so I reinstalled the 7805s back in place and back onto the heatsink. Nope...S&K with Sonic 3 attached still does the above regardless. I also replaced the 47uf 16v cap in the Sonic 3 cart in case that was part of the issue. No change.
Again, it would seem both games by themselves will play just fine. Though I did get a lockup in Hydrocity when playing Sonic 3 by itself. But this was much much later into game play. And my Sonic 3 has always been a bit of a toublemaker on my va2 HDG.
Ideas or has anyone ever seen anything like this? All other games I play on this system seem to work just fine without issue. I didn't test Virtua Racing but I probably should tonight. Also while I haven't tested lately, Game Genie use was never an issue either. So...yeah...