A while back I bought a non-working Amiga 2000 that, according the seller, only displayed a white screen. In the 80’s and early 90’s I only had an Amiga 500, so I thought it would be fun to now get a working Amiga 2000, and restoring one would be a nice X-mas holiday project.
Dealing with the Amiga Killer
One of the main Amiga 2000 killers is the battery, after 30 plus years they tend to leak and in the worst case can corrode away half the PCB. This one was no exception, the battery leaked and did damage, but not so bad that it was beyond repair.
At first glance the PCB itself seemed OK, but from the picture the seller send me it was already clear there was some corrosion on the CPU pins. After removing the CPU from the socket it was clear both the CPU and CPU-socket where seriously corroded and it was no surprise that the thing wasn’t working.
After trying the clean the CPU pins and socket it was clear both where beyond repair, and I ordered a brand new 64DIP IC socket and got a replacement CPU from eBay. The replacement CPU is a lot newer, the old one was from 1987, the replacement one is from 1989 :-) Since I had de-soldered the CPU socket anyway I cleaned the board and put some protective coating over parts where I removed corrosion to prevent the bare copper from corroding again.
At the same time I also replaced all electrolytic capacitors because those also tend to go bad after that many years.
And nothing …..
So time to give it a try, and nothing but a black screen. After testing all connections from the CPU to the ROM I found one broken connection. So time to add a botch wire on the back of the board.
Second Try …..
And time for the second try, and still no picture, but the machine seemed to work because it tried to access the floppy drive. After switching from the RGB port to the monochrome video output it seemed to work.
But of course a gray scale output would not be acceptable for this high end multimedia workstation. So after some careful inspection of the PCB, I found something that looked like a damaged trace. No idea how it got damaged (maybe when taking to board out?) but time for a second botch wire.
And Success!
This time the RGB output worked and everything seemed to work OK.
More Memory
The Amiga came with two expansion boards, a 2MB memory card and a SCSI controller. The SCSI controller had the possibility to add 8 1MB SIMM modules. So I went on eBay and got 8 1MB SIMM modules and put them in the SCSI card. Now of course the 2MB memory expansion board can not be used anymore because the Amiga 2000 can only deal with 8 MB expansion RAM.
After running a memory tester for a while, it seemed that everything worked fine. But since those old SCSI drives are hard to get I will replace it with a SCSI2SD board. Also I will put a Gotek floppy drive in it, making it all a bit more useful. But that is something for one of the next parts, because I am still waiting for the parts to arrive.