Has anybody come up with a fail-safe method for neutralizing the NES lockout chip? From what I've heard, the Codemasters circuit (consisting of a few discrete) components works the best. But does it work in all NES consoles, and even when a CIC is not present? Could anyone be so kind as to trace a Codemasters board and draw a quick schematic of the circuit?

I'd really love to have a cheap way to construct a universal replacement for the lockout chip since it would allow me to buy US SNROM carts to solder Years Behind on. NES carts are highly valued over here and the fact that Zelda, Metroid, Kid Icarus, Maniac Mansion and NES Open Golf are the only SNROM carts that exist in Sweden makes the matter even worse since the first three usually go for > $30 and the last two are pretty popular as well.

// Bananmos

http://www.girls-tacos.com/whoaman/nes-sec.zip should contain the schematic and 6502 source code used to operate it for the system Color Dreams used. Dan Lawton told me that he doesnt mind if people use this

I have tried codemasters KT-B-xxxx boards from camercia cartridges that use resistors, capacitors, diodes, etc. and an A/B switch with no sucess on an NES-CPU-11 with 3119A (circa '92, came with it) and 3119 (circa '85, from a joint board). The CIC was locked in reset mode, unless the CIC's lock/key pin was shorted to key for a microscopic ammount of time (it allowed the mickey mouse logic(less) to kick in).

The circut also worked with the CIC stuck as a key, and with the CIC removed (which prevents the reset button from working).

I only wish that I did not have to use video plugs to play the games because the voltage displacement was so bad.

> The CIC was locked in reset mode
what would happen if you used the CE on the PRG-ROM to activate the circuit to make sure the game is going before defeating the CIC?

Whoops, I see now that I somehow forgot to reply to this post. Thanks for posting this schematic! I'm really intrigued by their device. It was quite a bit more complicated to solder together than I expected though, so I dunno if it'll be that usable for replacing the original CIC on my homebrews. Nevertheless, their method was so damn cool that I'll have to try and build it just for the sake of it when I have some spare time. :)

// Bananmos

dont forget to include the circuit boot code in your source ;) otherwise it doesnt work