I'm going to open it up again later and have a look. I also want to check if the fan is working. The battery shows up at 100% in the OS X menu bar, but it's anything but full. Given the age I don't think I'd be able to recalibrate it (I couldn't do it on the original battery from my iBook so I just bought a new replacement).
As for the 800 I think I've managed to successfully reflow the GPU using the "hot coin" trick (I had borrowed a heatgun, but chickened-out). My first attempt didn't work. I don't think the coin was hot enough. So after leaving it on a gas ring for 20-30 mins I tried again. As soon as I popped it onto the chip I could smell solder so I left it to cool down. I had also placed a piece of folded tinfoil onto the chip as I didn't like the idea of placing the red-hot coin directly onto the GPU.
On the first boot, the screen lit up, but the hard drive didn't boot. Second time, the drive booted but the display didn't kick in. Third time around it worked. So then I left it for an hour or so to settle and tried again. Booted perfect.
I've just applied some Arctic Silver 5 to the GPU and replaced the yellow thermal pad (I managed to remove it intact using a paint scraper). I have an old Intel HSF sitting on it now to provide some weight/pressure. I'll leave it alone for another hour or so then try again. If it still boots up successfully, I'll put it back together and get Panther onto it.
AND
It didn't work. Still no display. Not having much luck with these at all.