Someone recently sent me their Amiga 1200, which used to be their pride and joy, for free, to look after. They no longer had a use for it. It needed a bit of work, so I decided to document it.

This Amiga

This machine came with a case that was not in great condition. One of the screw hole posts had snapped, and it had been painted black at some point.

It also came with an Apollo 1220 accelerator, which has a 68020 at 25MHz, a 68882 FPU and 4MB Fast RAM.

Testing

I took the machine out of its casing and booted Amiga Test Kit on it, a great sign that this booted. There was a hard drive inside the machine, but this wouldn’t even spin up, so this was set aside for another day.

Surprisingly, everything tested OK, including the accelerator. There doesn’t appear to be obvious capacitor leakage, either. I plugged in the keyboard and tried that out too.

Most of the numeric keyboard and right Amiga key have failed. This is an indication that a couple of the traces on the membrane are faulty. You can see the layout below. Although this is for the Amiga 500, the Amiga 1200 shares an almost identical membrane. From this, we can see that it is likely X7 and PB2 are faulty.

Whilst it might be possible to use conductive ink to repair wherever the failure in the membrane is, I’ve found this is almost always a temporary fix. It often fails again. I found a new membrane on eBay for under £30. So, I bought this.

Even the floppy drive worked fine. The ‘B’ here is marking a known issue with this particular floppy disk.

Keyboard Cleanup

The keys had signs of paint on and were not in the best condition anyway. I had a spare Amiga 500 Plus keyboard which was in better condition, the keyboard layout is identical and the keycaps are compatible. So, I cleaned these up ready for transplanting.

When pulling up the original keys, we can see how dirty things are underneath.

This needed a bit of a clean… After blasting it with air and wiping it down, I managed to get it a bit better. A quick brush after this photo would finish it off.

Next, the key caps from the Amiga 500 Plus keyboard went on. They could probably do with a little retrobrighting, but they are much better than the ones I removed.

Then the membrane replacement. Here is the old and new membrane.

Once the new membrane is in place, all the screws need to be put back in to hold the front to the back and allow the membrane to work.

I’ll revisit the keyboard when the machine is reassembled.

Recap

Whilst the capacitors have not had any obvious leaks yet, it is only a matter of time. I went ahead and replaced them. Most of them are Wurth capacitors, the 10uF ones are Panasonic, as this is what I had in stock.

As you can see, I also removed the TV modulator whilst I was at it. There are pretty much no use cases for this in 2023 and the space can be used for something else.

Testing

After this, I then plugged in the rebuilt keyboard to test it.

Using this, I was able to run Amiga Test Kit to try out the entire keyboard…

Looking good!

Reassembly

I managed to find an old Amiga 1200 case in excellent condition for sale for £60. I acquired this and started to rebuild the machine into that case.

The badge on the case still had the plastic protective film on it! I had to do the honours and remove it.

Conclusion

This machine came out better than expected. I have installed a PiStorm32-Lite with a Raspberry Pi 3A in it because it will be used for a special event in October. I will be wiring the Pi’s HDMI port to the space where the modulator was, so that RTG can be easily used.

I’ll be able to share more about how this machine will be used in the coming months. Watch this space!