Multi PCB stick help

[moose!]

I've got my stick running a solderless PSone hack in it and I'm trying to put in a PS360 pcb into the same stick.

I currently have all of the buttons/microswitches wired to a long screw in wire connector, with all of the earths comibining together, then out into the pad hack and so forth and works well.
Now I've stuck the PS360 in and just wired it up into the wire connector as well (including the single earth) and it no longer works on PS2 or via the PS360 usb (the PS2 freezes when it is plugged in, then continues when it's removed, the USB is registering every button held down). Any ideas what the problem is/am I not meant to be connecting everything into one earth on the PS360/am I an circuitry retard?
(I've been looking at diagrams etc for multi PCB sticks including the one in the sticky but I have two outputs so it works differently?)

Halp halp!
At the moment I'm kind of trial by erroring and hoping it fixes itself.

[moose!]

Never mind! Solved it!

Soldering wire to 3.5v spot to linking to Vcc input solved, did not realise I had to link the two PCBs like that.