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Eamoe · 15 October 2020, 23:15

Pay attention to debris around the working surface. If you encounter weird problems, check every place around and under the chips and sockets. Look for metal.

Many years ago I scored a rev 6.3 A2000 in very good condition. There was very mild battery leakage, which I properly cleaned and then I revarnished exposed traces.

It's a project I've been in and out of ever since, occasionally buying pieces of hardware and keeping it on the side, slowly collecting devices with the intent of making a great A2000 build sometime in the future. Hopefully before retirement.

In november of 2018, I completely recapped the motherboard. I got the Amiga to boot from an SD card controller attached to the SCSI controller. I was really happy, but then suddenly it started giving nothing but black screens. On rare occasions, I'd get a color. Sometimes green, or red, or purple...

Since then, whenever I got some spare time, I'd get to it and try something. I did everyhing, changing every single chip individually, reading schematics and checking continuity from every socket pin to destination, Nichicon-recapping the PSU, trying another PSU... This took very long, as you can already tell from my rythm of work.

Two months ago, I decided to change the CPU, ROM and Agnus sockets. I was medievally pulling out the last one of those, the Agnus one, and as the last bits came off, I noticed a small piece of straight silvery wire which had nothing to do there.

What happened was, a cut off leg from one of the replacement caps back in 2018 had escaped somehow and rolled right under the Agnus PLLC! It had been tucked down there ever since, wreaking havoc shorting several legs of the chip together...

A 2-year long fix. I hear your laughter from where I sit. I don't care. I did it. The Amiga works!

15 October 2020, 23:15	#259
Eamoe Stunt Car Racer Vet Join Date: Mar 2006 Location: Vevey/Switzerland Age: 43 Posts: 145	PCB work: be careful with metallic waste Pay attention to debris around the working surface. If you encounter weird problems, check every place around and under the chips and sockets. Look for metal. Many years ago I scored a rev 6.3 A2000 in very good condition. There was very mild battery leakage, which I properly cleaned and then I revarnished exposed traces. It's a project I've been in and out of ever since, occasionally buying pieces of hardware and keeping it on the side, slowly collecting devices with the intent of making a great A2000 build sometime in the future. Hopefully before retirement. In november of 2018, I completely recapped the motherboard. I got the Amiga to boot from an SD card controller attached to the SCSI controller. I was really happy, but then suddenly it started giving nothing but black screens. On rare occasions, I'd get a color. Sometimes green, or red, or purple... Since then, whenever I got some spare time, I'd get to it and try something. I did everyhing, changing every single chip individually, reading schematics and checking continuity from every socket pin to destination, Nichicon-recapping the PSU, trying another PSU... This took very long, as you can already tell from my rythm of work. Two months ago, I decided to change the CPU, ROM and Agnus sockets. I was medievally pulling out the last one of those, the Agnus one, and as the last bits came off, I noticed a small piece of straight silvery wire which had nothing to do there. What happened was, a cut off leg from one of the replacement caps back in 2018 had escaped somehow and rolled right under the Agnus PLLC! It had been tucked down there ever since, wreaking havoc shorting several legs of the chip together... A 2-year long fix. I hear your laughter from where I sit. I don't care. I did it. The Amiga works!