circuit bending...

sevenELIXIR · Post by **sevenELIXIR** » Thu Sep 25, 2014 2:25 am

twoists..... I need your help. I would like to open the top of my original Nintendo (NES) and do some circuit bending to cause some graphical glitches. for artistic purposes. do any of you know how to do this (without ruining the NES, or electrocuting yourself)???? here's what I'm going for:

https://www.youtube.com/watch?v=oAd_dQFUM4Q

Negamuse · Post by **Negamuse** » Thu Sep 25, 2014 7:16 am

Don't know about the NES particularly but in general... you should be pretty safe from electrocuting yourself as most of the circuitry is comparatively low power. (I think it's something like 9V in?) Either way, stay away from the bits near where the power supply comes in and you should be fine.

A lot of the fun of circuit bending is experimentation and with that there's a certain amount of risk that you're going to fry something. But if you wanted to be a bit more sure that you don't do that you could find a circuit diagram online and try and avoid doing stuff like wiring power rails straight onto chip data lines... Old video game consoles should be pretty good for glitching because you can see what's the CPU, what's the Video chip, so you can make good guesses for where you need to start tinkering.

mr3 · Post by **mr3** » Fri Sep 26, 2014 4:53 am

I'm way rusty, and I've never tried actually hacking the circuitry, but if you can't get pro help I can tell you what I'd try. For real simple stuff like tying lines together you could probably get by with just a few spare wires as far as tools go. As far as graphics, the easiest stuff might be tying together some of the GPU's output pins. It actually looks like that's most of what the guy in the video's doing.

NES graphics are handled by its PPU (picture processing unit), the RP2C02. If you take the console's cover off and pull out the main board, you should be able to remove the cartridge bay from it. Then turn the board so the edge with the black cartridge interface is facing away from you (ex. fig 1-4 here). The 2C02 is one of the two largest chips on the board. It should be in the middle, the one slightly to the left. You can probably connect pins on it (the metal pins coming out of the chip) for some basic tweaks, I'd just stay away from voltage and ground pins (look for a semicircular notch on one end of the chip, turn the board so the notch is facing left, and then the voltage pin should be the top left one and the ground should be bottom right). Mr. M's right, once you're on the main board it's standard +5v. For deeper hacks, you might have to dig deeper into the graphics side of the architecture, but wiki.nesdev.com's PPU section probably has everything you need.

If you want to do sound, that's done by the main chip, a 6502 variant called the RP2A03. My guess is that would probably be harder than it's worth compared to hacking on actual sound hardware though.

sevenELIXIR · Post by **sevenELIXIR** » Sat Sep 27, 2014 4:41 am

imagine I'm 5 years old. and repeat that to me. that's how much of that I understand

OverTheHorizonRadar · Post by **OverTheHorizonRadar** » Sat Sep 27, 2014 4:15 pm

I realize this is different from what you're looking for, but as a side note, software corruptions of the rom files for emulators can be pretty amusing. Example:

http://www.youtube.com/watch?v=twgzMRNEKWw

mr3 · Post by **mr3** » Sat Sep 27, 2014 8:50 pm

Sorry, not the best at explaining things. I'll send a PM, meanwhile I'd keep asking for help/info (ex. that corruption stuff can do a lot more if you wanna try messing around with emulators too/instead).