Love Locks at Pont des Arts

Amiga 1000 Restauration, Part 1

When the Amiga 1000 was launched in 1985, it was too expensive as a home computer, but rather targeted the professional graphics workstation market. The sales figures were correspondingly low. Only 27,500 units have been sold in Germany. Nevertheless, and without a doubt, the Amiga 1000 is the jewel of every Amiga collection. Now I finally had the lucky chance to get my own one.

The Amiga 1000, as I got it. The keyboard is a French/Belgian AZERTY type, with labels for the German keyboard layout.

The overall state is fine, considering that the machine is almost 40 years old. The Amiga itself is only a bit yellowed, but has some heavy scratchmarks at one edge. The keyboard has a French/Belgian AZERTY layout that was changed to German layout using stickers, like it was usual for the first machines that were sold in the EU. Its case and the space bar are much more yellowed. The stickers are also yellowed, and one is missing.

The expansion slot at the front contains a 256KB RAM module. The original mouse and the disks have been lost, but I can use any other Amiga mouse and make new disks myself.

What's Inside

Inside I found a Rev A mainboard and a piggyback board. That extra board stores the Kickstart that is loaded from disk when the machine is powered up. Later revisions used Kickstart ROMs, and didn't need this piggyback board any more.

The mainboard, and the piggyback board on top.

Usually all piggyback Amiga 1000 were produced for the US market. They could not run in Europe without modifications, due to different power frequencies and TV standards. My machine was produced in early 1986, presumably for the US market. One year later, it was modified for the European market. The original Agnus chip was replaced by a 8367R0 that is able to generate PAL video signals. The crystal is still the original 28.6363 MHz NTSC one though, so the video signal is not truly PAL.

The system has a Denise 8362R6, which is the first revision that is also capable of displaying the EHB mode.

Altogether, it is an early Amiga model, and very likely one of the first that have been sold in Germany.

The PSU

Generally I don't recommend to power up an old computer straight away after many years of storage. Without a visual inspection and the necessary refurbishment, the power supply could damage the computer, or components inside could blow up.

A first visual check of the PSU seemed to be allright, with no obvious damages, and no bulged or leaked capacitors. But then I found tiny cracks in one safety capacitor.

A look into the PSU. This RIFA capacitor shows signs of fatigue.

These RIFA X class capacitors are actually infamous for blowing up after many years. Their insulators are made from paper. The material gets brittle from age and thermal stress, letting in moisture, which amplifies the problem. Eventually the capacitor can crack open and go up in fumes.

It was good that I kept the PSU disconnected from mains. It is now being refurbished by @DingensCGN, a member of the A1K.org forum who has a lot of experience with Amiga PSU restauration.

The Mainboard

I recapped the mainboard and piggyback board. For the seven 22µF capacitors, I used a bipolar type instead. Those capacitors are used for filtering the audio and RGB signals. Using bipolar caps here might improve the signal quality, and won't hurt otherwise.

To be honest, this time I had doubt if I should replace the old capacitors. This Amiga 1000 will not become a workstation, I have other Amigas for that. It is rather a collectible. Still I want it to be in a good technical condition. When I started to collect retro computers, I promised myself not to keep machines that are broken or otherwise not fit for use.

After that I removed all the dust, and gave the boards a thorough wash with IPA.

The mainboard, with fresh electrolytic capacitors.

The mainboard is now ready to get remarried with the piggyback board, and then move back into the case.

Whitening

The first thing I actually did was to disassemble the entire machine. The plastic parts of the case were cleaned in soap water and carefully scrubbed with a dishwashing brush. After that, I used the sunny July weather, and whitened all parts in the sunshine. I did not use any chemicals, just the sun. After two days, the Amiga was almost white again.

All case parts are whitened and ready for reassembly.

That's it for the first part of the Amiga 1000 story. The next part will be about the restauration of the keyboard. There is a lot to do there.

Amiga 1000 Restauration, Part 2

In this second part, I will take care about the keyboard. I expected that it would be the usual procedure: Cleaning the key caps and case, whitening the yellowed parts, dusting off the keyboard frame.

The Amiga 1000 keyboard, before cleaning and whitening.

However, this time it wasn't that easy.

The trouble started when I pulled off the key caps, but also pulled out the plungers of three keys. Fortunately this can be repaired, as the switches are easy to maintain. More about that below.

Keyboard Cleaning

The key caps were cleaned in an ultrasonic bath with a drop of rinse aid, and then brushed with a soft toothbrush.

Below the key caps, there is the keyboard frame where the switches are mounted. I found the usual filth that you would expect there after almost 40 years, but there was also flash rust, a crusty dirt layer, and… dead insects. I went outside and brushed off the insects and all the other loose dirt. Then I went back inside, and sprayed the frame with IPA, in an attempt to clean off the crust. The room immediately filled with an unhealthy stench of dust, dirt, and insect excrements. 🤢 Also, my attempts to remove the flash rust with a fiberglass pen wasn't really successful. There was too much of it.

Yuck! Rust, crusty filth, and dead insects. My attempts to clean the frame in place were futile.

I wanted to avoid that I had to refurbish the frame, because it can only be removed after unsoldering all 91 switches (and one LED). But there was no other way to do it. So I unsoldered everything and removed the frame. On the PCB, I found dried stains from a liquid (maybe from a soft drink that had been spilled over the keyboard), and more dead insects. It confirmed that it was the right choice to go all the way.

Under the frame I found liquid stains, and more insects.

I sanded down the old paint and the dirt crust from the frame (outside, and wearing a good filter mask). Then I spray-painted it in a matte black. It's looking so much better now.

The frame, after sanding it. Freshly painted with matte black spray paint.

Refurbishing the Switches

The next bad surprise came when I was about to reassemble the keyboard. I tested all 91 switches for continuity when closed, but found only about 40 of them actually working. When I depressed the other keys, they either did not close the contact, or the plunger got stuck, or both.

The switches that are used in the Amiga 1000 keyboard are Mitsumi Type 2 tactile switches. They are out of production by today, but they are easy to maintain. After trying the best approach with a couple of switches, I found the following procedure to be most successful.

The switch can be opened by putting a kind of blade (like the head of a flat screwdriver, or flat pincers) into the latch on both sides, and then carefully removing the cap with a blade or another screwdriver. The switch consists of four parts: The cap, the plunger, the switch plate, and the base.

Insert a screwdriver or pincers, then carefully pull the cap from the base. From left to right: Cap, plunger (with spring), switch plate (with metal lever), base.

I cleaned the switch plate with contact cleaner spray. I also bent up the legs of the lever a tiny bit, so it will give a bit more pressure on the switch when the key is depressed.

Spray a bit of contact cleaner on the copper part in the center. If the contact does not close properly after cleaning, bend up the legs of the lever a tiny bit.

Finally, I applied a bit of silicone grease on both small sides of the plunger. It is important to use a very very tiny amount! If too much is used, the key will feel sluggish or might even get stuck.

Apply a very tiny amount of silicone grease on the bottom half of the small plunger sides.

After that, the switch was reassembled and tested again. If it was still getting stuck or didn't close the contact properly, the process was repeated.

It was a lot of work and a monotonous task, but at the end I could make all the switches work again.

Cleaned and refurbished keyboard, before putting on the keycaps.

Whitening

The keyboard case was cleaned in soap water. After that, the case (and the yellowed space bar) were exposed to the July sun for whitening.

The result is quite good, but on some parts a bit of yellow is still visible. I guess there would be an even better result if I would use peroxide, but I have no experience with that, and am not too keen to gain it with this rare keyboard.

The labels on some of the keys are still yellow, and wouldn't get any whiter in the sun. I guess that I will have to replace them with new labels some day.

Reassembling

With every parts cleaned and whitened, the keyboard was ready for reassembly. I pressed the key caps back on the keys, mounted the shielding, and then put the keyboard frame back into the case.

Take care when closing the case: One of the four screws is a bit shorter, and maybe also has a different color. This single screw must be used for the upper right hole.

One case screw is shorter, and has a different color. Use the shorter screw for the hole at the top right.

The keyboard restauration is completed now!

The Amiga 1000 keyboard is completed.

In the next part, I will reassemble the main unit, and have a first test. Is the Amiga still working?