Thanks for the reply, Steve. I've tried many things so far and the use of vinegar was one of them :) This is a long story that I didn't want to bore anyone with but here goes. My first experience with a Lisa 2/5 after acquiring one was a broken CRT that occurred during shipping. It still had the batteries in it so I cut those out and soaked the I/O and motherboard in vinegar/water to remove as much corrosion as possible. To fix the broken CRT, I sourced a DEC 12" mono CRT and replaced the yoke with the Lisa yoke. Unfortunately, the Lisa was dead when trying to start it up the first time (I couldn't start troubleshooting without a good CRT). All the while, I was a little skeptical that the DEC CRT would work. As a back up, I was lucky enough to find an empty Lisa 2/5 chassis (with wiring, motherboard and CRT) so I picked that up. This was an A6SB100 model with a Lisa 2 front bezel. The motherboard was also corroded but was different from my original motherboard. On this one, the mouse, needs a notched mouse connector that I assume was used on the original Lisa 1. I was able to clean "motherboard 2" with water/vinegar but the caps around the parallel port had disintegrated. I've since ordered those. While my original motherboard looked great, I did manage to break one of the pins in the 120 pin I/O board connector while giving it a light brushing. I am trying to find a replacement 120 pin as we speak for that. Even with bad caps, I tried both motherboards but no luck. I had checked most of the traces on the I/O board and found that I had to push in pins on the COP421 to make contact. I've replaced the socket since and could power up the Lisa with one of the motherboards!. After replacing the COP421 socket, my I/O board seems to be semi-working. My original Lisa 2/5 with the DEC CRT works fine (note for those who have bad burn-in) but I get an I/O board "Error 52" and that's where I am today. I think I may need a COP421 but that is kinda difficult to find and locating this is no guarantee that the I/O board is okay. So, I have two chassis, one set of cards, The original motherboard (with good caps and broken mouse pin on I/O port) is bad even though it's gleaming (and I tried soaking a second time just in case). The motherboard with the bad caps seems to be okay. I do have one keyboard but I don't know if it works. I have one Mac 128K mouse that I had to notch the 9 pin connector on to allow it to fit the Lisa 1 motherboard. Seeing as how I have some parts for a second Lisa 2/5 including a working power supply, I figured I'd see if anyone has any spare parts lying around because I think I've hit a wall. Other than checking continuity again on the I/O board, I'm not sure where to go from here. Sorry for the long post but in summary, I've been busy on it for a few months. Thanks for listening. Unfortunately, after looking for "Error 52" on the Lisa list and other places, it's a specific error for the COP421 but others have fixed it, in one case, by reseating the CPU board. It's getting a little frustrating but I'm determined! Ultimately, I'd like to get a Lisa 2/5 with LOS going, as opposed to Mac XL. I can revert my first Lisa 2/5 back with a few replaced ROM chips but if someone has some extra parts lying around, I may be able to get the second chassis going and possibly have both, hence the extended request for parts. It seems that I need a working Lisa to fix a Lisa :) Thanks again. On Sun, Apr 7, 2013 at 10:02 AM, Steven Hirsch <snhirsch at gmail.com> wrote: