Famicom to NES question

[mr_nihilism]

Can someone explain why my 31 in 1 Famicom pirate-cart (with adaptor) won't work on one NES yet play without a hitch on another? The pins in both systems and the cart itself are perfectly clean so that's definitely not the problem.

Thanks in advance !

[Dr. Morbis]

It could be an early pirate made before Nintendo started modifying and revising their lock-out. The older the NES, the greater the compatibility. This goes for unlicensed carts too.

[mr_nihilism]

Interesting. I have so much to learn still....