As this problem happened late last night I decided to leave it and see if I could fix it in the morning. Unfortunately the problem has gotten worse. I booted up the cabinet and the player 1 controls seemed to be working, so just to make sure I loaded up the ipac config utility again, but the problem was resurrected. Under the 'key editor' most of the buttons were replaced with 'unknown 212', 'unknown 223' and so on. No buttons are working what so ever now. I took the CP off and started checking the grounds. One looked questionable so I replaced it but everything else was quite normal. I went over them 2-3 times just to make sure but I don't see any other problems. I put the CP back on, booted up the system but it didn't help at all.
The light on the ipac4 is on, and having plugged it into my laptop as well, the problem persisted. It seems it can only be either my wiring or the ipac, but I don't think it's the wiring as I don't see any problems and it's been working great for weeks up until now.
Any ideas? I don't want to bug Andy at Ultimarc if I don't have to.