I have a couple of PSP slims. One has a non-functioning L-button and no amount of cleaning will make it work. It also has a randomly jittering analogue stick which I have just disabled using an seplugin after 3 replacement sticks did the same thing. The other PSP can't get past the date entry screen when you first turn it on because the X button does not work. I've cleaned and cleaned it but still nothing happens when you press X. Both X and L worked 6 months ago on the respective PSPs and they were kept in clean, climate-controlled storage. I'd dug them out with the intention of putting a large lipo battery in place of the UMD drive (I've measured: Adafruit has lipo batteries that will fit.) and connecting it in parallel to one of my many junk Chinese 1-hour (or less) PSP batteries. So much for that project.... Based on how unsuccessful I was replacing analogue sticks, I am very hesitant to spend one more dollar on replacement buttons or sensors. I've got GB, GBC, and GBAs that still work perfectly, whether I let them sit in a box or play them a bunch, so I am beginning to think maybe Sony build quality is not as good as Nintendo. Is there some trick to fixing these things? The buttons/sticks, that is.