Have the USB version of the IPAC 2, and I'm having some weird issues from time to time.
---yes I've followed the troubleshooting guide---
---IPAC was donated from another co-worker and is a few years old.  it's possible it just needs cleaning.---
1st issue - controls worked great during testing and regular play, then all of a sudden, the left direction on P1 stopped working.  solid green light on the IPAC.  I opened up the IPAC program and it confirmed the up direction wasn't working.  I replaced the wire, cherry switch, and quick disconnect...no dice.  changed the terminal for the 1up input to 1A, and it worked fine.  i thought i was good to go.
2nd issue - randomly one day, left on player 2 quit working.  i did the same thing as above, and changed the inputs, etc and it worked for a while.
3rd issue - now up on player 1 isn't working again.
i've uninstalled the device in device manager, rebooted, etc.  do i just have a bum IPAC, or does it need to have some contact cleaner applied to it?  or could it be a USB power setting (Windows 10 fully patched)?