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It turns out the best thing you can buy to help restoring an Amiga 500 is a second one for parts. My first issue was while I had pulled the A500 from its resting place out of the attic (where it has been sitting for the past 20 years) I didn’t find the power-supply. I looked for a few weeks in Ebay for a A500 power-supply listing but they seem to be very rare these days in the US. European sellers have quite a few listed but those would be good only for the physical adapter itself. There are videos showing how to use a common PC power-supply with the A500 but you still need the adapter for the A500 itself. The price for shipping one from the EU wasn’t worth it just for the physical plug.
So I purchased a second, reasonably priced A500 from Ebay for two reasons- first for the power-supply and second to have some spare parts for my original Amiga. It came with a working Amiga mouse which I also needed. It was a smart purchase as I very soon discovered that I needed the parts to get a working Amiga.
The new ‘spare’ A500 after taking what was needed. This was actually my original A500 that I started the project with.
As it turned out – I ended up using the 2nd A500 purchased off Ebay as my final, working A500 while my original one became the parts donor. The reason was simple- my original A500 (I’ll call it Green LED) worked fine once I had a power-supply and mouse. When the HC508 accelerator was plugged in it wouldn’t boot. I couldn’t diagnose Green and I found that the HC508 worked fine in the new (Red LED) A500 from Ebay. The Red A500 was an older rev Amiga and it has the red power LED. Being older it has a Agnus chip with just 512k chip ram. For WHDLoad you need 2Meg chip so a MegaChip was going to be required in the near future.
Issues discovered and fixed to create a working A500:
- Dead Floppy
- Broken keys
- Bad CIA chip
The CIA replacement solved a issue with the mouse. It would only move horizontally. Swapping CIA chips one at a time till the mouse moved normally fixed that. The dead floppy on Red was fixed by just swapping from Green A500.
Both A500s had keyboard issues- Red had an entire line of keys dead, while Green had a dead Return key. Complete disassembly of both keyboards allowed me to understand what was going on with each one and then fix the Green keyboard which was installed in the Red A500. To start I watched some videos on Youtube and read some blogs about A500 keyboard issues and it soon became apparent that the printed circuit sheet (the green membrane) had issues on both keyboards. The Red had a broken circuit and would have required a patch but the other keyboard membrane (Green) just needed a disassembly, clean up and reassembly. Sometimes the keyboards can end up pinching the membrane causing issues with keys and just loosening screws around the pinched area can resolve issues. This worked and allowed me one working keyboard- not having a working Return key is frustrating.
The end result was a working, powered, booting A500 with my HC508 accelerator with working floppy and mouse.
Update: I went ahead and purchased the A500 USB keyboard adapter on Ebay from electronika4you. They are in Poland and they make a variety of adapters for Atari St and Amiga.