I built an Amiga 4000T motherboard replica two years ago. It was a fun build and a great way of getting to know the A4000T model that I have had little experience with. Naturally, when the PCB was offered for sale I jumped on the possibility to buy one even though I did not really have a master plan.

An example of this no-plan setup was that I had no idea what case I would use for it. Though I assumed the situation would fix itself either one way or another in the future (as it usually does).

The A4000T is an interesting Amiga. It is the last C= Amiga computer and it is different from other Amiga models in certain areas.

For example Commodore used daughterboards for various functions and offered it in a really cool full tower that later was replaced with another style (even more cool looking) full tower by Amiga Technologies.

Difference between Amiga 4000D and Amiga 4000T

Compared to an Amiga 4000D the difference between A4000T and A4000D are:

While the A4000D is sort of Baby-AT in its form factor it does not follow PC guidelines for the Baby-AT format as it has ports soldered to it on the back and i slightly larger.

Amiga 4000T compatible cases and finding the right case

The Amiga 4000T motherboard follows the AT standard and should fit large AT cases. It can also fit EATX (Extended ATX) cases with modifications.

Original Amiga Technologies Amiga 4000T case

When I was a teenager this was the coolest Amiga case ever -I think- but from todays perspective I think it has some problems.

• First problem, it is a huge case and the space is not really optimized well, and even if it was optimized well I would not need that much drive bays these days.
• Second problem, it is impossible to find one. Good luck finding one!

The Amiga Technologies A4000T case was actually just a regular PC case from Enlight. There are similar cases from Enlight that occasionally pop up on Ebay that can be used but if you want the original prepare to wait and save money for the rare occasion it shows up or hope that someone makes a replica.

AT cases

Can you use AT cases for the Amiga 4000T motherboard? Yes in some cases, depending on if the case has enough space for the motherboard. In the 90ies, there was both AT and Baby-AT cases.

The A4000T is AT, it is a larger size than Baby-AT. When I researched cases I found that many full size AT towers could fit the A4000T if you ditched the internal 3.5″ bay.

Most AT cases has the DB9 and DB25 cutouts at the back for the IO module and mounting holes for the motherboard should match.

ATX cases

Can you use a modern PC ATX case for the Amiga 4000T motherboard? Yes, with some modifications it is possible to use a standard PC EATX (extended ATX) case for the A4000T motherboard.

The A4000 is a huge motherboard so it wont fit shallower ATX cases. The case has to support EATX. EATX is wider than regular ATX.

There are a few problems with going the ATX route. But all of these can be fixed by modding the case.

1. Some screw holes for the motherboard do not line up correctly in the case.
2. There is no space for the IO module. To be able to access mouse, joystick, parallell and serial ports from the back you will need a special A4000T ATX I/O board that is available here (or wire up ports directly to the motherboard pin header).
3. There is no space for the disk module to be accessed from the back of the case.

PC AT tower case for A4000T case mod

As said above I did not really have any plans on what case to use but I found this old beige PC AT case on a local trading website and I instantly thought for myself, could the A4000T motherboard fit into that?!

I thought it looked small, but after spending an hour in Photoshop adding the A4000T motherboard on top of a side pic of it it in a separate layer I thought it could actually fit inside.

Believe it or not, I actually had an AMD K6 in exactly this case almost 30 years ago. Maybe it is the same case? What comes around goes around.

The case has three 5.25″ drive bays and one external 3.5″ drive bay and two internal 3.5″ drive bays. It also has space for a front 80 mm fan. As the case will be heavily modified I expected all of the drive bays to be non usable once the A4000T motherboard is fitted inside. The case also has this unnecesarry door that slides up and covers all the drive bays. I remember it was a major PITA BITD, but it sure makes the case look clean with the door closed.

DISCLAIMER

I want to point out, the aim of this project was to find a case for an Amiga 4000T replica motherboard. As such the goal was not to make a showstopper but an actually working setup that would enable the Amiga 4000T to be used regularly and reliably. It is not the most beautiful case in the world but for real world use this project makes the A4000T motherboard usable without hunting down an unobtainium or 1000+ euro case.

The picture above shows the case with the cover removed. Cases do not look like this anymore, it was nostalgic to see a case like this again, though I prefer modern black cases.

The AT and Baby-AT form factors disapeared from the markets almost 30 years ago and was replaced by ATX. ATX gave us bigger cases until Mini-ITX became viable alternative. Some ITX cases are the same size as Baby-AT cases. I always wanted a BoXeR in a small Baby-AT case. That never happened though and after 30 years, I think it is fine and not something to get upset about anymore, there are so many badass alternatives these days that the BoXeR is just a faded, if not very cool, memory now, if all.

This picture shows one of the problems the case had. There was simply no way of installing the large Amiga 4000T motherboard in the case without cutting off the 3.5″ drive bays and the horizontal support shelf under the PSU at the back of the case. The A4000T motherboard is simply too tall to fit otherwise.

The picture from the back of the AT case shows cutouts for DB9 and DB25 connectors. The IO daughterboard can simply be installed here, however some other modifications are needed, more on that later.

Also, take notice of the keyboard connector hole that lines up with the A4000T motherboard beautifully and the 7 slot card openings that lines up with the A4000T video slots, daughter boards and Zorro slots. Inside, the motherboard almost lines up with every hole inside.

Another look at the inner piece I had to cut off. I do not have access to power tools so I had to come up with a way of sawing it off with a metal saw.

I do not enjoy doing sheet metal work in my living room, often it turns out really bad and amateurish looking. But sometimes you have to be bold, I think this was such a time.

Modifying the PC AT case for the Amiga 4000T motherboard

To be able to do the nesesarry modifications I used a hand powered drill -that I suspect is 100 years old- to drill out the rivets for the upper side plates. This drill has been with me through many Amiga case mods during the years, a lot of Amiga case mods, maybe too many Amiga case mods.

The side plates had to have the horizontal stability plate that sat under the PSU cut off. The internal 3.5″ drive bay was easy to remove as it was just riveted to the case and just had to have its rivets drilled out.

I did not take any picture of sawing pieces off but imagine spending four evenings with a metal saw blade like a mad man. Whatever it takes.

I could finally do a test fit of the motherboard when the pieces that blocked the motherboard from being installed in the case was sawed off.

I was really surprised to find out that there was space left to use the upper 5.25″ drive bay even after the motherboard was installed in the case. I was really happy to find it fit the case well but there was still a ton of stuff to do. I had to push on.

As you see on the image, there is no way I will be able to use a regular AT or ATX PSU, not even an SFX PSU would fit so that was something I had to solve.

Here is another image from the front from test fitting the A4000T motherboard. There is an alignment issue with the upper part of the case so I had to use shorter hex standoffs there. The case was a bit flimsy at this point as the upper right sheet was removed.

And here is a picture from the back of the case to see if the keyboard connector would line up with the hole for it – and it did.

Another picture that displays the space left over the A4000T motherboard.

I used this riveting tool to rivet the sides back to the case once they had been cut off and modified. I bought it back in 1999 when I was modding my then A4000D into a PC mini tower case. See that case below.

And here I am almost 30 years later using it again (for the second time) for the same purpose.

Make no mistake, the rivets and riveting tool works great for securing case sides and makes for a very stable case again.

Test fitting Amiga 4000T motherboard, daughter boards and Zorro cards in the modified case

I was now at a point were I could test fit cards and other hardware in the case to get a feel for what would fit and what would not fit.

One thing that hit me is how roomy the case is, inserting full size Zorro cards is a no-brainer in this case and is a real pleasure to do. The daughter boards unique for the Amiga 4000T also fits great in the case.

The daughter boards can be accessed fine from the backside.

Full size Zorro cards fit without problems in the old AT case. Even my A2386SX slides in and out without problems here. That is great for being such a small case relative to the original A4000T case.

But one problem was quickly noticeable, the Zorro boards are offset slightly. I fixed it by adding spacers under the brackets.

Finding and installing a PSU that would fit in the case for the Amiga 4000T

There was no space for a regular ATX, AT or SFX PSU. After an intense brainstorm session were I played with the idea of using a Pico-PSU and an laptop charger I Instead opted for a NOS thin Flex-ATX PSU.

Flex ATX PSUs are smaller than a regular PSU and are quite popular these days because of tiny PCs. This PSU has 12a on the 5V line and has a total wattage of 250W. I have always steered away from PSUs with 40 mm fans because they usually create a ton of noise. This PSU is not an exception, but the noise level is not that bad to what I have heard before.

So how do you fit an Flex-ATX PSU to an AT/ATX case? I found this ATX-PSU to Flex-ATX PSU converter on ebay. It is a thick plate of aluminium and makes it possible to use the Flex-ATX PSU in a normal case.

The adapter plate fit great and holds the Flex-PSU securely in the case.

This picture shows that there are plenty of space for the A4000T P8/P9 power connectors and the turbo card. As the Flex-ATX PSU is short the case can still take a full length 5.25″ drive in the upper bay.

One problem with the Flex-ATX PSU was the cables. They were long and took up a lot of space in the case. Just look at the image above. What is not shown is the AT to ATX adapter taking up even more space.

So I cut off cables I would not need. I also wired the AT to ATX adapter directly to the PSU and shortened cables. This made a huge improvement to cable management in the case.

A picture from the top shows cables neatly tucked under the PSU. I saved some SATA power cables because you never know, could be usefull in the future.

Wiring up the I/O board to the A4000T motherboard

The I/O board gave me a couple of problems. The first problem was to find suitable D-SUB connectors. The D-SUB connectors on the Amiga 4000T I/O board has to be a little bit taller than regular straight D-SUB connectors as otherwise the I/O PCB board will hit the case.

The D-SUB connectors I got was quite expensive but options were few. The only ones I found was D-SUB connectors without threads for the hex nut so I had to glue nuts to the D-SUB connectors with Epoxy glue. It was a nasty solution but works.

I used a strong epoxy glue and let it cure for a few days. The picture above clearly shows the extended D-SUBs needed.

During a test fit of the I/O board I found out that there was no space for the pin header. The I/O board is hooked up to the A4000T through two 40 pin cables called short and long. The pin header is usually facing down from the board on the front side but that would not work as the they would hit the case.

So what I did was that I desoldered the angled pin headers and soldered straight pin headers to the back of the I/O board instead.

Then I ordered four 20 pin single row cables from AliExpress and hooked everything up. As it was not entirely clear how to exactly mount the cables I accidently hooked them up wrong.

But after thinking really hard for 30 minutes (including drawing up a routing scheme) I figured out the right way the cables should be mounted and everything worked as is should. Please keep in mind that the cable is installed in the wrong direction on the picture above and below! This part of the project was extremely confusing for some reason.

I am very happy with how it turned out. However I would prefer 40 pin cables as they are easier to insert and remove. Maybe I will wire up custom 40 pin cables in the future because these 20 pin cables need a lot of force to be inserted correct into the pinheaders.

Modifying the 3.5″ drive bay to fit the case with the A4000T motherboard installed

I do not use floppy drives anymore but I had this 1.76 MB floppy drive in my stash that I got in a trade for free and thought why not. Could come in handy in the future. To fit the drive bay it had to be cut on one of the sides to make way for the motherboard and I had to figure out a way of securing it to the case as it was riveted to the case.

Interestingly it has a small speaker on the underside. The small speaker actually comes in handy since the Amiga 4000T has a pin header on the motherboard for a speaker that can play Paula output (controlled by the turbo button).

To secure the 3.5″ drive bay I screwed it down on one side with a nut and screw. As the 3.5″ floppy drive sits a bit tight in the front of the case it does not really matter that only one half is screwed to the case. It is not perfect, it is a bit flexy when ejecting floppy disks but works fine.

And here is the Amiga floppy drive installed in the A4000T case. Now, what to do with the upper 5.25″ bay?

Installing something in the 5.25″ bay

I installed a CD-ROM drive in the upper 5.25″ bay just for completion purposes. It is not like I actively use CD-ROMs anymore. I would prefer a ZuluSCSI or Compact Flash bay here instead and will probably exchange it in the future for that.

Installing power button

With all DIY projects there are problems that needs to be solved, even with a silly power button. The screw holes for the power button did not fit the case so I super glued hex brass nuts to the front and screwed down the power switch to them.

I did try to find a better fitting power switch but found nothing that would fit better.

Figuring out a better way of mounting the Amiga 4000T motherboard to the case

Some mounting holes on the motherboard lined up with hex standoff nuts already installed for installing the motherboard in the case. There was also space for these plastic plugs. I was disappointed that the motherboard was not really that securely attached to case with the mounting solution of a few brass hex standoffs and plastic plugs so I looked for an alternative.

What I came up with was to use two washers and a brass standoff with a slightly longer thread.

Here is a hex standoff with a washer.

And here is how the brass hex standoffs are secured to the case by screwing it down with a nut having the case back wedged between two washers. I put Loctite on the threads to make them stick and I also glued washers to the case before screwing them down tightly.

This is a great picture that shows all mount points for the motherboard. What I especially like is the full support around the ISA and Zorro area. Inserting or removing a Zorro card leads to minimal flex in the motherboard or the case. Inserting and removing Zorro cards is pure pleasure in this case, even bridgeboards thats slots into both the Zorro and ISA slot. Please note that there are hex standoffs on the upper area too, the A4000T motherboard is huge!

The Amiga 4000T motherboard is fully secured in the AT case. I thought everything was fine but I had just created a big problem, can you guess what?

Fixing offset problems for daughter cards and Zorro cards

The problem was that adding a 1 mm washer under the hex standoff pushes the motherboard further out. That meant that cards did not sit flush against the back of the case.

Off course I could have fixed this with shorter brass hex standoffs. But as they were already screwed down tight and glued and loctited I just decided to find another solution. And that was to add some thin washers under the bracket for the daughter boards.

Kinda weird but the Zorro boards sits further out than the daughter boards. So I needed thicker spacers here. I do not know what it is but no matter what Amiga project build I work on I always have problems with offset cards in all my builds – so I was not surprised here.

I used epoxy glue to fix them to the back. It is possible to 3D print something to fit here or to order some custom machined plate. Maybe in the future. It might look naff but the spacers actually work, cards sit very solid in the case.

Final thoughts

While the build is not finished yet, the case sure is. In its current state it has a Multifix scandoubler, and a Matze graphics card. A 256MB memory card and a Zorro-LAN-IDE card. There is also an AmiGUS in it and a cool red BFG9060. There are small things to do here and there like cleaning up the cables, adding power to the CF adapter and installing a ZuluSCSI, a bridgeboard with ISA cards will also go into this case. Building a bad-ass PPC workstation is also a potential future for this build as it has the potential for much better case cooling than the A4000D has.

And I must not forget, I need a boing ball badge for the front.