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Old 26 June 2014, 08:23   #1
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ajk's Avatar
Join Date: May 2010
Location: Helsinki, Finland
Posts: 802
My A500 project (many photos)

Hi. I thought I would post a bit about an A500 project I've more or less managed to finish now.

The A500 was the first Amiga I got when I was young, and it was such a great machine after the C64 I have since collected a bunch of other A500s over the years, and I don't really even know which one is the original one. Anyway, I thought I'd put this stuff to use and build one perfect A500 setup "to keep".

First I had needed to think about what I want from the setup. I'll probably keep a separate floppy-only A500 as a spare, but I wanted this one to be a bit more upgraded. Back in the day we eventually had an A590 hard drive, which made playing multi-disk adventure games so much better. So also with this project a hard drive and some extra memory was a minimum requirement.

However, I also want to keep the system easy to set up and storage, so this ruled out the A590 or any other external hard drive. I'd also want some extra RAM, but probably not really any other extras. The system should look totally plain and original.

So, which motherboard to use? I happened to find a rev 8A board which belonged to an A500, not A500+. This meant that the clock circuitry and therefore the battery was never installed, and the board was in pristine condition in that regard.

No leakage here.

However since this was an A500, it also only had the 512kB of chip RAM installed. This would not do, so I added a few sockets, tweaked a few jumpers, and upgraded the memory to 1MB.

But since the board did have a 2MB Agnus, why stop there. I put together Yulquen74's RAM board and expanded the memory to the full 2 megs.

While I was doing this, I also cleaned the board, changed all the electrolytic caps (they weren't leaking but I want this board to be good for a long time to come, and not have to repair it). While there was no battery corrosion, several of the IC sockets were otherwise oxidised. I replaced all of them with good quality turned-pin ones, also the big 68000 socket and the PLCC Agnus socket. Some other connectors were also replaced with fresh ones.

For the hard drive and extra RAM I chose the DCE Viper 520CD board. This provides 8 megs of fast RAM, IDE ports and a 33MHz 68020 (also Kickstart 3.0 but I already have 3.1 installed on the motherboard itself).

I needed some way to access the hard drive, or in this case CF card, but I didn't want to cut any holes in the side of the case. However, as the trapdoor memory expansion is so small, there is plenty of space on the other side of the bay. I installed a CF card reader there. I did have to make two holes for the M3 standoffs, but they are small, tidy and in the bottom so it's OK by me.

I left the original floppy drive in (after some cleaning), since the system will have a hard drive and plenty of capacity for running games via WHDLoad. I still occasionally play with actual floppies so the drive is nice to have.

Now everything was basically wired in.

Second part coming right up...
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Last edited by ajk; 16 August 2016 at 14:47.
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