So I build a NES to Famicom controller adatper with a 4score (PAL as it is virtually useless to me given the IC is different) and it is working fine except for the zapper (it does not fire). I followed the instructions located here http://www.famicomworld.com/forum...
I have 3 different zappers and all 3 work on my NES on the same TV so that rules out a broken zapper or TV compatibility. The Zapper will fire when I unplug it from the adapter but even when aiming at a duck it does not register a hit. If I swap D3 and D4 (I thought I had them backwards at one point) the Zapper will fire but again does not register a hit. Does anyone have any ideas here as to what the issue may be?

Thanks!

Do Zappers work correctly on a 4 score in the first place?

It is rewired with wires directly to the nes pins from the famicom plug. The only points used in the 4 score are power, latch, and ground.

Plug it into port 2?

I wired it up to allow the zapper on port 2-4

Congrats then.

That does not mean that it is working, simply stating how I wired it.