Faulty Snes, only plays specific games

OK I picked up a snes that has a weird issue, Basically most games do not work at all, but "rise of robots" will work perfectly fine, space invaders will work on the menus but freezes once you go to start a game, It has had the caps replaced and the board all looks pretty clean, although it does appear someone else has already had a look at it as it had some tape along the back and the power switch was snapped and botched together

anyway, just wondering if anyone has any suggestions on what might be wrong or has experianced anything similar

 

I'm guessing you've cleaned the pins on both system and carts? Maybe worth replacing the pin adapter. It could be that cart has really thick/clean/long contacts or something whereas most others aren't making good contact.

 

So _Rise of the Robots_ works? Maybe your SNES just has really bad taste?

I have seen consoles with bad WRAM that would run some games but not others.

 

Oh yeah I tested the cart slot from another system and it didn't work either and the one from this console worked fine in a working system

OK I tried the diagnostics cart thing, that doesn't work but I also tried a copy of super boss gaiden I had been playing and on this console I get a red fatal error screen with "error while unpacking LZ4 file", a bunch of extra stuff that may help identify what caused the crash, but idk if it would help tbh , I am feeling like it sounds like a ram issue but just wanted some more opinions first, I may have a old dead board I can try pull stuff off, but just wanted to make sure there isn't anything more obvious I'm overlooking

 

let me guess, its cpu is S-CPU A..... for some reason the cpus on the models with revA go bad, there has been a ton of testing if you look around for it, this forum and others have data, and someone even did a proof of concept where they had a board acting this way, and took off the revA cpu and put on a revB, and it solved the problem... i also have experienced this, as i have a revA snes similar to what you described as far as care and cleanliness, and it literally ONLY plays Brandish and no other game...

 

OK well I can confirm it was a CPU-A board, in the interests in figuring out the problem I dug out some old chips I had pulled of a badly damaged snes board a few years back, they weren't in the best of shape but luckily the S-WRAM and CPU chips still had all their legs intact, so I figured I would swap them over and see what happened, I made a video after swapping the S-WRAM I found that prior to the swap mario all stars also worked on the snes for the menus so that's what I was using here

as you can see the wram didn't seem to be the issue, even after swapping it out it still acted the same, so next up was the CPU, now it is another CPU-A I replaced it with, but now with the cpu replaced it is actually playing most games now, only one that has had issues so far was megaman 7, but I still need to give both chips one last cleanup to rule out that being the issue with mm7 I also need to test more games as I only tested 7 or so

but yeah figures I would share me experienced and hopefully I can get this 100% working, I'm actually pretty pleased the chips I pulled finally came in useful

 

nice to see a second confirmation on this tactic, as there was only the one guy who did the CPU-B swap, obviously if you have a good working cpu-b snes, you shouldnt kill it to revive a cpu-a one.... but if youve got a damaged and non working one... or simply a better condition, less dead cpu-a

 

Well it turned out it was just the contacts on MM7 needed a clean, now its all working good with everything i have thrown at it, so yeah under normal circumstances this issue would probably not be solvable as i doubt many people would happen to have a spare SNES cpu lying around,

this cpu was pulled off a board that had been left in a shed and was badly corroded on the back end. so luckily the CPU was mostly in ok shape, i actually cleaned up the board when i removed everything off it as i wanted to use it in a little project, it actually cleaned up well considering, anyways i made a scan of it and did some virtualboy-esque filter over it, figured it looked kinda cool, so to finish off this thread enjoy a nice picture of a bare snes motherboard, who knows maybe it will help someone do some tracing or something

Spoiler