Seems that my left nub is mechanically broken. It was acting up shortly after I'd had my unit RMA'd to fix the PTOD, so I tried pressing down on the case around the nub as suggested in another thread. This worked for a second, but then the nub started drifting around like crazy, refused to calibrate, and sometimes wouldn't physically center itself. If I rotate the nub I can usually get it to recenter, but it still drifts around to the point of uselessness. I switched it to mouse button mode, and it kind of works, but that's not exactly a fix. I'm not too eager to spend another month waiting for a repair. Is it possible for me to fix this myself, and if so how would I go about doing it?