Can anyone tell me what the purpose of switching out the Nes' .1uF capacitor with the 1uF one while installing the CopyNES / USB CopyNES? As far as I can tell, this sits directly between the cart and the lockout chip.
Probably just to beef up its ability to smooth out power supply spikes. When CMOS chips change state, they draw current, which causes a temporary dip in the supply voltage. A large dip can cause erratic operation. The capacitor provides extra current closer to the chips, reducing these dips. When you add more chips that can be switching at the same time, you need larger/more capacitors.
Hmm, thank you for your reply.
The reason I ask is because I have been having trouble with unlicensed games that use surges to circumvent the CIC permantly frying the copynes somehow (it's happened to me on 2 seperate systems now), and they did not have such problems before I installed the copynes... I'm wondering if this capacitor putting out extra power could be overloading something? It is really frustrating, I am not very experienced with hardware troubleshooting.
Judging from the types of issues I'm having (and previous advice), I think the problem is related to the surge used to circumvent the CIC, since it is already disabled in the CopyNES, In my next implementation, I am hoping I can completely prevent the surge from going anywhere, but I am having trouble isolating the path it takes.
Is there a way to ensure this surge only goes to ground without affecting anything else? Could some kind soul advise me on what would be the least painful way to accomplish this (or if it's impossible without serious modifications)?
crade wrote:
Is there a way to ensure this surge only goes to ground without affecting anything else? Could some kind soul advise me on what would be the least painful way to accomplish this (or if it's impossible without serious modifications)?
The lockout chip communicates solely via pins 34, 35, 70, and 71 on the cartridge connector; you could probably just cut those traces on the NES motherboard.
The main purpose for the bigger capacitor has something to do with giving the system a slightly longer reset period, presumably to give copynes some extra time to init. It was either kevtris or bunnyboy that explained this to me a while back.