Still no progress on fixing it, but I’ve eliminated some things that aren’t causing the problem!
I installed a new SSD and did a clean restore from the Pismo 9.0.2 CD. Restarted and… same thing, trackpad responds for a minute and then stops. Interestingly, the mouse button doesn’t work either once the trackpad stops working - which is a little odd considering that the trackpad connects via a flex cable to the main logic board, while the mouse button is on the power board, and connects through the logic board / power board connector.
Ok, time for a full teardown…
The good news is that most everything is in pristine condition. Logic board and CPU board both look great. Modem looks fine (not that I’ll be using it), and I got the top case, display, and inverter board all removed without any problems. I have a bunch of pictures, but in the interest of saving space I won’t post all of the things that look good. The LCD is in great shape, the case isn’t as abused as many of these are.
Now for the bad - something definitely got spilled in here. The power board had clear signs of corrosion, there is green corrosion residue on the edge of the top case and around the mouse button plastic, and some on the bottom case. Like I said earlier, the keyboard and DVD drive showed some evidence of gunk as well. Fortunately it doesn’t look like any got onto the CPU board or logic board - it all went toward the front of the machine and the drive bay.
I cleaned up the corrosion on the power board as best I could with IPA. I also tried resetting the PRAM again, and shielding the track pad from the power board with an anti-static bag (in case the power bad was bad and was emitting a bunch of EMI or something - there is a stick on EMI shield over the Maxim switching regulator controller from the factory, so the power board clearly is somewhat prone to emitting EMI). No luck.
One thing I did notice was that when I flexed the top case a certain way I could get the trackpad from “unresponsive” to “somewhat responsive”. When it was “somewhat responsive”, the mouse button would work. When it was “unresponsive”, the mouse button didn’t work. I suspect that when it’s “unresponsive” that something in the system ignores the whole thing, even though the button isn’t on the same board as the trackpad.
The bottom of the trackpad PCB looks great, but I can’t see what damage or corrosion might be present on the top side, or in the layers of the trackpad itself. Unfortunately, the trackpad is part of the top case assembly, sandwiched between the plastic and the metal frame, which is plastic riveted to the case plastic. I’d need to cut all of the rivets to get it out, and then I’d need to glue it all back together in the end. Even if I could get it out, I’m not confident that it would be repairable.
I was able to find a replacement top case online for a reasonable price, so I have that on order (hopefully it’s real and the order will actually be processed/shipped). I also ordered a replacement power board on eBay - I think it’s unlikely to be the problem, but for $12 it was worth a shot.
This project is starting to take on a Ship of Theseus vibe - I’m already in for a new power adapter (missing), SSD (dead), top case (suspect), and power board (who knows). A full rebuild would require a new PRAM battery and a Li-Ion battery rebuild… we’ll see if I take it that far.
