Annoying dual mod problem. Help!

I have a t5 ps2 pcb linked pwr and grnd to dreamcast.

On dreamcast the L and R buttons work fine. L and R on dreamcast merge with L1 and R1 on ps2.

when I test L1 and R1 on ps2 they dont work!! all the other buttons work fine on both systems. The only problem I have is L1 and R1 not functioning. Does anyone know what can cause this? Wires are fine also.:smokin:

its whatever diode your using, not sure if it has to be stronger or weaker though

sounds like a soldering issue. try grounding the button signal and see if it activates.

i thought it was a soldering issue but i tried it again on another dreamcast pcb and another ps2 pcb and still the same problem. when I unhook the commons from each other with powers still connected it works fine but its a must to have the grounds connected for a dual mod. I dont wanna have to use a ground switch.