Buttons only fire when moving

[S1500]

So I was doing testing of all my hoarded CV hardware last weekend. Amazingly, it went pretty well. Only 1 console & 1 controller was wonky.

 

Haven't had time to open it up yet, but the fire button(s) only worked when I was moving in a direction while playing Gorf.

 

Anyone know what it might be? I plan to open it up & clean the connectors and such, but never saw a controller do that. I used other controllers on the same console, and they worked just great.

 

I'm starting to think I didn't need these replacement controller chips + sockets from console5. Guess they go into the spares bin.