Is there a way to disable the Camerica voltage spike?

[Thenewguy]

Back in the day unlicensed companies had to work out ways to disable the NES lockout chip to get the NES to run their games. Codemasters, who made games published by Camerica found out they could get the cartridge to deliver an electric charge to the NES to stun the NES lockout chip so that the game would not trigger the protection and could be played as normal.

Is there a way to disable this? My NES does not have a functional lockout chip anyway so I don't need this to happen.

[ComradeOj]

I'm not totally familiar with this form of lockout bypass, but I've heard of it here and there. I think the voltage spike is directed toward the lockout chip directly. In that case, it might not really matter if you disabled the lockout chip anyway.

According to this pinout, pins 34, 35, 70, 71 of a cartridge go to the lockout chip. https://benheck.com/Downloads/NES_Famicom_Pinouts.pdf

You could maybe cut these traces internally in your NES, assuming the knockout voltage is coming via these pins. Never tried this, so your results may vary.

[Thenewguy]

I had heard that 34 and 70 were the lines that the anti-lockout chip worked on.

I did wonder if I could just duct tape over those lines on the cartridge so they didn't make contact with the NES or something

But really I was more wondering if I could just pull bits out of the cartridge to stop it.

[Thenewguy]

According to someone who worked on the Game Genie, the switch literally just turns it off

Apparently the Toploading NES didn't have a lockout chip, so the current just goes somewhere its not supposed to, hence "Position A" turns it off.

Not useful for me though as mainly I was only asking because my cartridge keeps crashing and I was guessing it might be due to the current going to the NES, obviously now though I find out I had it turned off the entire time anyway, so the cartridge is probably just broke.

Good to know that the cartridges I have that do work aren't going to do any damage to the NES though.

[Thenewguy]

Absolutely my last post on this, promise.

So I seem to have "fixed" the game!

I was actually pretty much right, the lockout defeater was causing the game to crash, it was just happening in the cartridge, not the NES.

I just pulled out this transistor and it no longer crashes

Attachment 16512

I'm hoping this won't cause any other problems, I mean, the switch on the cartridge itself is always set to "off" anyway. Either way I will only use this cartridge on my bad NES for a while, just to make sure its not doing any damage or something.

My guess, as a complete noob, is that the lockout defeater is pulsing the electricity into the NES to stun the lockout chip, but that there's another component in the cartridge to protect it from the defeater messing with the chips, and I guess the one in my cart had failed or something?