Friend of mine has a NES I haven't looked at personally yet but he says it displays corrupted graphical data (he isn't more specific) but the sound, controls, etc all function just fine. He has recently replaced the 72 pin connector. Any ideas? Only things I can think of might be dirty cart contacts or maybe bad RAM chips? The thing worked fine for the last 20 odd years.
Considering that the video ROM bus go through the cartridge connector I would suspect of that. And also being it replaced recently makes it very likely a suspicious sopurce for the problem.
The Nintendo I had growing up had this problem. After years of kids beating up the system, games would work flawlessly maybe 1/10 times. The rest of the time, the graphics were garbled and corrupted despite the game being completely playable. There were also a lot of instances where vertical lines ran down the screen. I believe the source of this problem is cartridge mis-alignment. Someone bent the cartridge slot's springs on my old NES, so the force keeping it in was asymmetrical (which could slowly allow the cartridge to bend the pins). The pin connector itself could also be loose. So just go over it, make sure none of the pins are bent or dirty/corroded, and make sure the slot mechanism is balanced. Do all of this and you should be good! :thumbsup: By the way, how old is this Nintendo that you're working on? Does it have the basic Nintendo repair sticker on the bottom or the one with Mario holding the screwdriver? I'm only curious because my problematic NES was from late 1992, so it made nearer to the end of the console's production.
On Nintendo hardware ? Difficult ... On Nintendo hardware which has no Surface Mounted Devices ? Almost impossible... Again I say have the newer/replacement connector inspected. Also if it's possible have the connector tested on another NES. It's possible that ESD (Electro Static Damage) happened on the CHR RAM or PPU chips. :shrug:
Confirmed it tonight. The 72 pin connector had two pins that didn't look like the rest, after pulling them out the dip in the pin itself was about 5mm back from where it should have been. Probably wasn't even coming in contact with the cart at all. Swapped in one from a fully functional NES and it worked great.
Great to hear it. I've had some dodgy connectors too, even new as they are, some aren't as good quality as others.
