Yet another A4000 DIY tower guide!
(This one's for the technically inept)

This page is a description of my tower conversion effort for my A4000, and is designed to provide those of you who feel like attempting it some help. I decided to create this page, as I felt there wasn't a single page available which really gave me the tips and help I needed to be sure I was doing the right thing in pulling apart my functioning A4000 to rehouse in a PC tower case.

Disclaimer: I take no responsibility if you blow your Amiga (or yourself) up whilst attempting rehouse it. You do so AT YOUR OWN RISK. Whilst it is pretty straightfroward, there IS a level of risk involved. However, if you plan, think clearly, and DON'T PANIC, then it is a straightforward and worthwhile exercise.

One very full Amiga 4000 - notice how the CD-ROM drive blocks airflow to the fan, and the IDE cable is in danger of being eaten by the PSU's fan.

What you need

- Amiga 4000 desktop machine
- PC tower case - the bigger, the better
- 2 PC 9-pin male serial port plugs
- 2 PC 9-pin female serial port plugs
- 10-wire ribbon cable (length dependent on the size of your tower, although one metre should be enough)
- 5 1/4" drive bay converter for a floppy drive

- multimeter
- angle grinder
- spare grinding disks (depending on how much cutting is needed)
- electric drill - pliers
- various sizes and types of screwdrivers
- soldering iron
- solder
- pot rivet gun
- pot rivets
- screws or bolts and nuts (size and number depend on the tower case you have - mainly neede for mounting the joystick ports on the tower case)
- ruler
- pencil
- eye protection (for using the angle grinder)

- patience

How to build your DIY tower case

1. Buy a tower case. The higher, wider and deeper it is, the better. The one I settled for is 56x40x20cm, and had 4 x 5 1/4" external drive bays, 2 x 5 1/4" and 3 x 3 1/2" internal bays, plus 1 x 3 1/2" external bay, which couldn't be used with my A4000's internal floppy, as the drive is too big to fit. I wouldn't recommend getting a tower smaller than the one I got - sure, you can still do a successful DIY with one, but it will require more work than the method I used. Also get one with an AT PSU (not ATX, as it doesn't work with an Amiga motherboard - don't ask why, just take my word). My tower has a 300W PSU - more than enough for most uses. Look around for a secondhand one, as you'll save a lot of money that way. (I had to remove the internal 5 1/4" and 3 1/2" drive bays, as they wouldn't fit with the A4000 motherboard inside the case - more on that later).

The secondhand case I bought for AUD $20 (US $12)

2. Plan. I cannot over-emphasise the need to plan what you are going to do. I did this extensively, yet still made a couple of silly errors.

3. Disassemble the tower case. This is where I made my first mistake, as I didn't notice that the bottom drive bays weren't welded in, which later caused a silly mistake (which didn't affect the finished product though). Remove the tower's PSU, as you will be using the angle grinder on the tower case. Also removes any plastic fronts, LEDs, and so on.

Make sure you keep the various screws and bits separated and labelled for later.

4. Disassemble the A4000. The beginning of the transformation. This is pretty straightforward. I did it in this order.
1. Remove any Zorro cards.
2. Remove the hard drive(s) and whatever you have (if anything) in the 5 1/4" drive bay.
3. Disconnect the IDE cable and the floppy cable.
4. Remove the floppy drive.
5. Remove the Zorro daughterboard. Undo the screws on the supporting bar, and it should just need to be pulled out like a normal Zorro card.
6. Remove the processor card. The A4000 hardware guide is a useful guide for this.
7. Unscrew the two screw holders on the serial interface - I used a socket set to do this.
8. Unplug the power cord from the motherboard, and the LED cables.
9. Remove the plastic front of the case.
10. Unscrew the motherbaord and remove the motherbaord - there are nine screws - one or two can be hard to reach.
11. Remove the PSU.

One disassembled Amiga...

5. Rehousing the A4000's case inside the tower case. This idea was provided by Kleng, and is the best way to have a backplane for the tower case, with a minimum of fuss. Look at the back of the tower case - there is a space for PC expansion cards - this is going to be the basis for the backplane. Through this hole (which probably will need to be made larger) is where the A4000 case's backplane will emerge.

The idea is to trim the A4000's case so it will fit inside the tower case, so it is just larger than the motherboard (so all nine screws can be re-inserted to hold the motherboard in place, and so all I/O ports are still on the backplane, and part of the front, so the supports for the Zorro cards are still there, and the hole to screw the supporting bracket back in). This means, in effect, that the bottom part of the A4000's case is cut in half.

When you are measuring this, don't forget to allow at least 1 1/2 cm for space between the edge of the A4000's case and the bottom of the tower, as the joystick/mouse ports are here. This stage is the most critical of the entire project, as it should hopefully be a good fit. Use a ruler and pencil to draw guide lines on the tower case and the A4000's case.

This is the last chance to turn back - cutting the A4000's case means you can't rebuild it in it's original case!

When you have cut the tower case's backplane and modified the A4000's case (I used the angle grinder for this), line the A4000 case up correctly inside the tower case. This is where I made a mistake - I didn't take out all the drive bays which I could from inside the tower case, so I had trouble getting the A4000's case inside, so I kept cutting the hole in the tower case bigger and the A4000's case smaller. Once I did remove the drive bays, there was no problem. Before I did this, I considered buying a pre-made tower case - the shock of how much it would cost from my local dealer made me press on, as did the two month wait to get one.

I spent AGES doing this step, just because I didn't remove those drive bays, and kept trying to get the A4000 case inside the tower. Make sure you wear goggles whilst using the angle grinder.

Drill holes through the A4000's case and into the frame of the tower case, and pot rivet the two together. You should now have a solid tower case and supports for the motherboard, as it just screws straight back into the original holes on the A4000's case.

To make it easier to insert/remove Zorro cards, drill four holes in the bottom of the tower case, so you can insert a screwdriver to reach the screws which hold the Zorro cards in place.

The A4000 case inside the tower case. It is pot-riveted in several places - enough to keep the A4000 case firm. Make sure the pot rivets are not higher than the raised circles on it.

5. Wiring up the extension cables for the joystick ports. Use the PC 9-pin serial port plugs as the plugs which you will plug your mouse and joystick(s) into, and use the ribbon cable to join the two sets (one male and one female/set!). The female plugs plug into the joystick ports on the A4000's motherboard, and the male ends are screwed to the tower case. I haven't provided a wiring diagram, as it's pretty simple to do (i.e. - pin 1->pin 1; pin 2->pin 2, etc.). Be careful not to heat the ribbon cable up too much whilst soldering, as it is very thin. The alternative is to simply buy a couple of pre-made joystick extension cables.

6. Rebuilding the computer. You are now on the rebuilding phase of your A4000. The hardest part is behind you.

Cut the plug off the A4000's PSU, about 4cm away from the plug, as you will need this. Use the diagram below as a guide. The tower's PSU has a number of wires and plugs coming out from it - two plugs are for a PC's motherboard (twelve wires in total, between the two plugs). The Amiga only needs six. Find the long flat plug which has six wires and voltage levels (use your multimeter to check) like the one in the diagram below:

This is what your Amiga motherboard plug looks:

The Amiga's plug has the same voltage levels, but in a different order. Use the diagram below to wire up the plug correctly. I used a plug which is very similar to the A4000's plug, to join the two sets of wires.

The colours represent which wire from the tower PSU goes into which socket on the Amiga motherboard plug.

Check the voltage levels of the plug, to make sure that it is wired correctly!

Replace the tower's PSU in the tower.

Put the A4000's motherboard into the tower case, making sure that you have plugged in the joytsick/mouse extension cables beforehand. Screw the motherbaord into place before you put the motherboard into the case. Bolt the joystick plugs to the correct-sized slots on the back of the tower case (ther should be several of them to choose from). Replace the little bolts you removed from the serial port socket when the motherboard is seated and screwed in correctly.

The motherboard back where it belongs.

Plug the motherboard power plug into the motherboard (you DID check the wiring with a multimeter, didn't you?).

Replace the Zorro daughterboard and the support brace across the top of it.

Replace the processor card. Once this was in, I realised I couldn't replace the drive bays I had removed. It isn't a big loss, as I don't have very many devices which need bays. There is a lot of air circulation around the processor card, and a lot of room for a G4 card and its GFX card :)

This is the time to test your machine, in case you made a mistake with the wiring, so you don't blow it all up. Turn it on. If you are sure you didn't make a mistake, then leave this until later.

The Amiga fully back together inside the tower case.

The floppy drive - the 5 1/4" drive bay adapter you bought is probably too small, so cut the top strip of it off, and now the A4000's drive should fit perfectly into it. Screw it into the adapter, and then screw the adapter into one of the 5 1/4" drive bays in the tower. Plug one of the PC floppy power cords into the floppy drive (the wiring is the same). Plug the floppy data cable into the motherboard and the drive. You may need a longer cable (I didn't) - if so, first try mouting the floppy in the bottom drive bay, if you haven't already.

Mount your hard drive(s) in the correct empty drive bays. Plug power cable(s) into the hard drive(s), and the IDE cable into them and the motherboard. You might need a longer IDE cable - I did. Same goes for a CD-ROM drive/ZIP drive, etc.

Replace any Zorro cards you have (you will now appreciate those holes you drilled in the bottom of the tower case).

Replace any other form of expansion you have.

Plug in your mouse and monitor.

Cross your fingers. Pray. Do whatever makes you feel better.

Turn your machine on.

If you did everything correctly, then you should now have a working A4000 DIY tower!


The back and front views of the completed tower. Notice how the back of the A4000's original case pokes through the new casing of the tower.

Little touches - plug the LEDs from the tower case into the A4000's motherboards, so you still have a power light and one for the hard drive.

I sprayed painted my tower case, as the tower didn't look too good, and the drive bay adapter was a different colour anyway.

Ultimately, it was a pretty straightforward exercise, which required more courage than skill. I am not an engineer or an electrician, and am not very good with power tools, but I managed it easily enough.

Now all I need is a G4 card and a "Boing" sticker for the tower!

This project wouldn't have been possible without the help of the following people/guides:

Kleng, who provided me with the idea of using the A4000's case, as well answering my many questions. His own page has a DIY tower guide, but it's in Norwegian!
The A4000 hardware guide, for various A4000 information, especially the motherboard plug's wiring;, for the pin-out of the PC motherboard plug.

Whilst you are here, why not take a look at my main web project, Die Toten Hosen - Until the Bitter End? It's the only AUSTRALIAN site for one of the world's best bands, and my personal favourite, Die Toten Hosen, who are from Germany.

Uploaded on January 26, 2000 by Anthony Long.