I finally decided to get the Lisa 2 I've always wanted. Made a deal for one on ebay with keyboard and mouse and Profile drive for $850 -- powering on but not booting. I think I'm more or less in line with the market there, maybe a tad high.
It's a 2 (or 2/5) with battery corrosion issue on the I/O Board and a bit on the motherboard near the RS232 port. There is a little chip on the motherboard (74SLxxx something I believe) that had one leg rusted out. Here is what I've done so far:
- Soaked components in 50/50 vinegar/distilled water solution for 12 hours, rinsed with distilled water, blew dry, let sit for 24 hours, cleaned any flaked rust with toothbrush
- Followed all traces passing through the damage zone to verify continuity, and patched any thing along any broken ones in. (there were a couple of resistors on the negative trace that leads to the negative battery terminal that I had to patch in with wire
- Checked continuity with the socketed chips to verify that each pin was making a connection to the socket, and the socket to the underlying traces. Pin 13 of the COP421 was having trouble, so I patched it by slipping in a wirewrap wire to that socket (secured in there with pin 13 against it) and then soldered the other end on the other side of the board to where the socket leg for pin 13 sticks out. Verified continuity.
When I first got the machine, plugging it in produced nothing other than the power button light and a red light somewhere in the drive cage. After doing all the work above, the screen now comes on to an Error 52 (COP421 error). Once or twice, by accident, I got it to come up to a different error where it asked to boot from a different device (but keyboard and mouse did not work). But usually it just beeps and comes up to Error 52. And there's a little H up in the upper right of the screen all by itself.
I guess my question is, given the attached photos of the damage -- would I be better to abandon this and just start hunting for a replacement I/o board (ie. do the mod that allows you to run a 2/10 board in there)? I'm wondering if others have experience repairing this sort of thing successfully. Also wondering if there's any way a novice without an oscilloscope (yet) can diagnose the COP421 chip to see if it's alive.
So I guess in short -- what would you do? Advice greatly appreciated.