ToToTEK.COM

[dvd]

My SWC DX2 64, which I purchased from FFE years ago, has developed an issue with the ROM degrading when the game is running. If I load a ROM from the ZIP drive and then play a game, random bits in the game get toggled but only when the game is running.

It hasn't rendered the unit useless though, because it doesn't seem to affect every game. But some games, it seems to affect more than others.
And, there are games that have the issue now that didn't have the issue before.

1) If I load a game into the unit and then copy the game back to a zip disk and do a file compare, the files match.

2) If I load a game into the unit and then start the game with the RTS manager, when I return to the menu and copy the game back to a zip disk, semi-random bits have been swapped in the ROM.

3) If I then reload the ROM back from the zip disk I can return to the game with the bits fixed, but the whole process starts again.

4) I have done a lot of tests with the game that gave me the most trouble, Castlevania Dracula X. I came to a point in the game where some of the enemy sprite graphics were messed up, and even one point where the enemies were invisible... so THAT's why I get hurt at random times!

5) I say semi-random because in testing CDX if I start the game and then immediately go to the menu and save the ROM, very few bits have swapped. If I run it some more, and then return to the menu, more bits get swapped. If I reload the game and start again, only some of the same bits get swapped.

Basically, there seems to be a set of bits that have the potential of being swapped. Every time you play it is chooses some of these bits to swap, but you can't predict which ones.

6) Its not a LOT of bits. I was able to pass Castlevania Dracula X and a number of other games since then.

7) I did try buying another SNES unit on the off chance that it might fix the issue, but it seems to have no effect.

I did take the unit apart and tried to see if anything was loose or shorting, I tightened what I could but it didn't seem to have any effect.

9) This is actually my 2nd SWC DX2 64. The first one FFE sent me was defective and they actually paid for me to send it back and send me another one since they had sent the first one in poor packaging which probably damaged it. The problem it had seems very similar to this one except much more extreme. I test 4 games with it:
- SMW played perfectly, I played the entire game on it before sending it back.
- Street Racer - As the title screen played, the graphics would start to disolve and eventually the game would lock up
- BoF 1 - Would start to disolve but would never lock up until you started playing the game.
- DQV - Would always lock up early on the ship.
I've since played through all of these games on the current SWC without any issues.

My setup is on an original style SNES with parallel ZIP 100 and external power supply to power the disk drive. Originally, before I had the zip, I used the floppy drive exclusively, but now I only use the floppy to save my BBDs to both the ZIP and the disk for redundancy. As far as memory access is concerned we previsouly used it to play the 48Mbit Tales of Phantasia twice without a single issue.

I'm wondering if anyone else has ever had a similar issue? I think the fact that it doesn't hurt the ROM unless the game is running is the biggest clue.

Any help would be appreciated.

[CrackLtd]

This issue sounds very wiered and i have never heard of it before. Since you describe it very well but i still don't know what you mean with 'some bytes swapped' maybe you can make some screenshots and let us see that mystic failure. Since from what you describe it seems a graphical glitch mainly. I have the SWC DX2 64 also but i have the DiskDual as expansion box, equipped with a CDRom drive and a 2GB harddisk, and no Zip drive. Maybe its also a good idea to rule out the Zipdrive or the ROM as possible source of the failure by using the internal floppydrive. Also easy things you can do yourself: Is the used PSU powerfull enough (SNES), is the internal battery still ok? If something else is broken like the RAMS or any of the logic, i guess you can't repair that yourself and you would need some professional service.