My A500 project (many photos)

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ajk

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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.

First, I needed to choose a motherboard. 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.

a500_1.jpg


No leakage here.

a500_2.jpg


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.

a500_3.jpg


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.

a500_4.jpg


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.

a500_5.jpg


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).

a500_6.jpg


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.

a500_7.jpg


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.

a500_8.jpg


I chose a keyboard with the proper layout and also one which was relatively unyellowed. I could of course retrobright any keyboard, but the results don't necessarily last. A keyboard that has lasted (more or less) white this long, should do so in the future. I also chose the case the same way - it is slightly yellowed but probably will never get worse than it is now.

a500_9.jpg


I wanted a way to see when the hard drive was accessed. The accelerator board has a header for an LED, and also the CF adapter has a tiny LED of its own. I didn't want a nasty 5mm LED just botched onto the case, so what I did was separate the two LEDs that comprise the floppy indicator light. One still indicates the floppy activity, and the other hard drive activity. Here is a GIF animation showing how it works.

a500_15.gif


At this point the system was pretty much complete. Doesn't look like much on the outside :D

a500_10.jpg


I did a quick Workbench install and tried the system out with a little test display I have.

a500_11.jpg


And here is the obligatory Sysinfo shot.

a500_13.jpg


Pretty nice for an A500, I'm happy with the end result :)
 
Awesome work - what a superb A500! Love the LED's.
 
Do you have difficulties when you want to remove the Viper card from the precise CPU socket?

J.
 
Most impressive, love your attention to detail and also that slick LED hack :)
 
:thumbsup: Very neat mod. Great that you didn't need to make any major changes to the case other than the mounting holes for the CF card.

Bryce.
 
Thanks for the comments all :)

@JanciB

The card comes out quite nicely by using the handle part of a toothbrush or something similar as a lever. As long as you push straight up evenly from first one end, then the other, no pins get bent.
 
Lovely job... some nice attention to detail, especialy the dual LEDs.
 
Fantastic implementation mate. That's a lovely A500 which will give you years of joy :)

Kudos.
 
AJK that is an outstanding LED mod! (and very nice a500 all round!)

Did you just snip the legs at the PCB, bend them up and then solder your LED cable to them?
 
Last edited:
@djos

Thanks! The original circuit has two LEDs (combined in one plastic housing) in series with a 22 ohm resistor. I cut a trace on the keyboard PCB to separate the LEDs and swapped the resistor with a 120 ohm one, bridging one lead of the resistor directly to one LED. This leaves that LED working at the same brightness as earlier, and the other one completely separated from everything on the PCB. Then I soldered two extra wires to the separated LED and connected those to the header on the Viper.
 
Nice work, I might try something similar with my Kipper CF-IDE-RAM expansion. :)
 
First words from me are "Jammy...." lol

Finding an Rev8 board, inside an A500. With no clock ever being installed means its just mint! so lucky, im a bit green with envy lol.

Also that led mod you have done is very inspiring! do you have any pictures of what you did? I wonder if the same thing can be applied to an A1200 led board...
 
@ElectroBlaster

I didn't do much, basically there are already two LEDs on the keyboard PCB, they are just molded in the same plastic to create a single wide light. I cut the trace on the PCB so the LEDs are separate, and also replaced the original 22 ohm resistor with a 120 ohm one to maintain roughly the same brightness. Then I soldered extra wires to the, now separated, other LED and routed those to the Viper board.

I guess you could do something similar on the A1200, but since it already has a light for both the floppy and hard drive, why would you need to? :)
 
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