This problem with my IPAC4 just cropped up.
Sometimes I'll hold the joystick diagonally but only one of the switches will either register or remain registered as I hold it in place, so my guy will run up or down, or left or right, but not diagonally. This is happening probably about 20% of the time. Because it just started happening and is true of both joysticks, I know it's not a restrictor problem. If I quickly re-center and move back to the diagonal I'll almost always start moving diagonally, but it's a royal pain to do that and makes games like NBA Jam or shooters unplayable.
It seems like maybe there is a problem with the ground, or there might be a short somewhere, but before I started messing around with the wiring I wanted to see if anyone had any suggestions as to where to look first, if they'd had a similar issue.
Thanks.