A few months back, an AmigaLove.com user contacted me about help getting his Amiga 2000 up and running after a decade plus of hibernation. I haven't worked on an A2000 yet as most of my experience has been the A4000, A500s and my A1200. I offered to take a look at it, but he would have to send the board from FL and have to be extremely patient!
A few weeks later, the bare board arrived. I knew it was going to have battery damage and cautioned him that it might take me several months to get around to it. Too many projects with my personal
clock cycles limited due to work, baseball season, domestics, and the occasional bout of apathy. But, I also wanted a bit of a challenge, as well as the desire to see another Amiga live again.
The board revealed was terrifying. Corrosion was intense. This was going to be a heroic salvage.
What surprised me was the extent of the damage. The accumulation of years of storage and the evils of Varta (Varta, Destroyer of Worlds ©) had done their best to render this board unusable. I also had the fortune to have access to the Sacramento Amiga Computer Club's (SACC) stash of Amiga parts-including several Amiga 2000s in various working states. One of those boards was a badly abused and stripped down rev 6 (312722) PCB. I originally was advised to chuck the board but I am glad I didn't. It became a valuable reference later on.
The corrosion process had crept all the way to the CPU and kickstart ROM sockets. Despite the damage, it was important to verify the current working state. My basic test setup consists of a known working A2000 PSU and my trusty OSSC (self-built, mind you
). Unfortunately, black screen with the video signal sync at the normal 263P signal @ 15.73khz output. This was both good and bad. It let me know the clock was working and that Denise was doing her job. But, it also meant that without even getting to a CPU startup, we wouldn't even get some color codes to help with troubleshooting.
Removing the CPU and kickstart revealed damage on many of the interconnecting traces and my troubles would likely be there.
Several washes with white vinegar, followed by denatured alcohol not only signals the start of restoration, it also promotes damage to one's sense of smell! The fiberglass pencil is incredibly useful to stripping off the damaged PCB mask and removing the corrosion. But after a short while, your hands will start feeling like you have knots for muscles and that is no fun. Once all the components were cleared out of the area, it was time to break out the big guns.
Enter MR. DREMEL.
Yes, that's right. The hobbyist's best friend. The Dremel. And today's ammo of choice is the 511E Finishing Abrasive Buff, starting with the 180 grain, and finishing with the 280 grain buff. Very careful and gentle touches on the bare board quickly stripped the remaining corrosion and solder mask down to the bare metal. Additional cleanup with of the damage and many many washes of denatured alcohol were the needed to remove the last of the crud.
We're still a long way from a working system, but at least most of the corrosion was done with. I say most because, later on, minute amounts of corrosion would re-emerge from the vias. The bottom of the board was pretty healthy. I noticed a slight amount of corrosion opposite of the battery and keyboard connector. Letting it sit for a few days and studying where new corrosion would emerge was valuable in chasing down the last of it. This was going to take a while.
Meanwhile, my mostly-trusty desoldering station (a ZD-915, pretty much the same a lot of the budget ones floating around) suffered from an unfortunate accident. The glass tube that contains the molten solder in the gun had rolled off the workbench one day while cleaning. Needless to say, I knew I'd be down for a bit while waiting for a replacement. This gave me a chance to keep an eye out for any new corrosion signs-which did happen and were mitigated immediately-until we finally saw no more new corrosion.
Did I mention that Varta is an evil Djinn?