Restoration of a barn find Amiga 2000: part 1

I recently acquired an Amiga 2000 for £350 which was in an unknown state, but had many upgrades in it. There is a lot to go through with this machine, so I’m going to break this up into multiple parts. For the first part, I’ll see if I can get the motherboard working.

The Amiga 2000

A local seller had several machines for sale that were a “barn find”, luckily I saw the post quickly and asked if I could purchase their A2000. A few days later, I made the trek to pick it up. To be fair, it looks like it is in pretty good condition for a barn find, even if the keyboard and mouse are discoloured.

You may notice the sticker that says “040” on the front. This is due to one of the upgrades in the machine. It has:

• Harlequin frame buffer (I think the 4000 version)
• ICD 2000 SCSI Board with 105MB HDD
• Progressive Peripherals 68040 Accelerator

There is also a battery which has caused a little corrosion too.

Of course, I immediately snipped this out and cleaned up the corrosion. I also tested the traces on the edge of the 68000 CPU, and they were all good. I swapped out the CPU for a clean one, just to be sure the pins are going to make good contact with the newly cleaned socket.

Testing

I decided to test using my own power supply for now, until I know the one that came with the machine is good. I powered it on, and…

It struggled to boot, often resetting itself or just crashing. Not a great start, it is going to need a little work. I pulled all the cards to trim it right down to the bare motherboard, and I was still not getting anywhere.

I then plugged in DiagROM, I had to bend a pin back so that I could use the serial port, this could be an indication that someone plugged the RGB cable into the serial port in the past.

Suffice to say, DiagROM wasn’t happy.

The serial output was slow, corrupted and the output was bad. This could indicate a few different issues, but the most obvious one is Agnus. I popped Agnus out and checked the socket.

The socket looks a bit tarnished, so I used a fibreglass pen to clean the pins and tried again.

Bingo! We have a booting machine. From here, I shoved the 040 accelerator back into the machine to see if it would still boot.

As we can see at the bottom, we have a 68040 CPU with 2MB of Fast RAM.

Kickstart

Now it is time to pop the Kickstart ROM back in and attempt a boot with that.

The SysInfo output confirms that this is a 68040, claiming to be clocked at 28.5MHz. Apart from PiStorm, this is probably the fastest A2000 I’ve ever used!

I think I can safely say that the motherboard is working now, as is the accelerator. The accelerator has an old, noisy 12v fan on the CPU, I think that will need changing for a much quieter one as I complete this machine.

PSU

The PSU was still had its factory seals on, I figured I would open it up and test it before I put it back in the machine. The main reason for opening it is my first Amiga 2000 had a Rifa capacitor inside it, hidden behind the power socket. I always swap them out first as they will combust with age. Unfortunately, in that Amiga 2000, I didn’t spot it until it was too late and smoke filled the room.

Anecdote aside, let’s look inside this PSU.

It is almost immaculate inside, no dust on the fan and hardly any inside. The capacitors look fine and they are good quality brands.

I tried to do a voltage test with just a hard drive attached, but the PSU kept cutting out and restarting every second. My best guess is that whilst the hard drive was loading the 12v line, it wasn’t loading the 5v line enough, as that is likely what is used for regulation.

More testing is needed.

Next steps

Now that I have the machine running, there is a list of things to do:

1. Get the original PSU running.
2. Test the rest of the cards in the machine.
3. See what is on the hard drive.
4. Test the floppy drives.
5. Clean and test the keyboard and mouse.

In addition, I may do these optional things:

1. Change the fan on the accelerator.
2. Swap the hard drive for a BlueSCSI v2.
3. Add a new RTC battery.