Now that the motherboard work is finished, it is time to rebuild. Lots of 3D printing involved in this one, let’s dive in.
Using neat rust remover wasn’t working as well on the tiny bits of rust around the case. Instead, I used a Dremel with a sanding tool to remove as much as I could, and then polished afterwards. This improved things a lot.
For the PSU I am using a 500W “be quiet! SFX L Power” power supply with a wire harness to convert ATX to Amiga 4000. This power supply has a very quiet fan and is very reliable. I have used it for quite a while in my Amiga 4000.
Horizontally, the power supply fits perfectly, but vertically it is much smaller. So, we need something to support it, as well as support the power button. I used this 3D printing design to do just that.
Now the motherboard and Zorro daughterboard get installed. Here is where you can see a couple of extra goodies I installed as well.
The left black card is a ZZ9000, which I used in an earlier post in this series to help diagnose one of the video issues. It provides an HDMI output, ethernet and several other things. The back card on the right is a BFG9060, which is a 68060 based accelerator card with 128MB of RAM onboard. Both of these have been removed from my Amiga 3000, I have plans for that machine, but that is for another day. The CPU is a rev. 5 68060 with MMU and FPU running at 50MHz.
You may remember, near the beginning of the blog series, that the floppy drive looked like it had taken a beating.
The face is cracked and the eject button is broken. But, does the drive work at all? Time to test in Amiga Test Kit. I used an Amiga 500 motherboard for this because it was simpler to wire-up at this stage.
All green! This drive is definitely worth saving. It is actually a Chinon FB-357A. These are great drives because they can read HD disks, which isn’t easy to do for an Amiga. To do this, it has to run at half the speed of a normal HD drive.
The first thing I did was to 3D print a replacement for the eject button. I went with this design on Thingiverse. It also included hooks to repair the face of the drive if the clips were broken, but that doesn’t help me.
At first, I decided to glue the face back together, this worked really well, but I wasn’t happy with the final look. I figured I could make it look as good as new. So, I decided to design a completely new face.
This is the first revision alongside the original face.
It needed refinement, it needed a door, and it needed to use a more appropriate PLA colour. I ended up using my A600/A1200 colour-matched PLA to print the eject button and the final version of the face. It took 7 revisions in total, this was mostly down to me breaking the clips every time I tried to fit it. This is around revision 5:
The design isn’t exactly the same as the original, but I’m quite happy with it. The print lines are almost invisible, you need to shine a strong light at them (like I did here) to see them. I have made this design available on Cults3D.
Now that we have a floppy drive, there is a 5.25″ bay that is just itching to have something installed. How about a CD drive? I have an 8 speed Panasonic drive that I pulled from one of my RiscPCs that is begging to be installed in something. I installed this into the drive bay and screwed the drive bay back in. As a bonus, I found a CD in the drive!
You can see that I also installed a Buddha IDE card for the CD drive, and I have installed a CF card reader to the rear of the machine to boot from. In addition, I have now installed the RTC battery and hidden it below the PSU. It is secured there with double-sided tape.
The final finishing touch to the hardware is to install the machine’s faceplate. This is the final look of the machine. If I retro-bright the faceplate in the future, it will end up a similar colour to the floppy drive. That is a decision for another day.
Finally, the machine needs an OS. Time to install Amiga OS. I could just do a blank install, but since the accelerator and video board came out of my Amiga 3000, I should just be able to clone the hard drive image. The Amiga 3000 uses a BlueSCSIv2, which uses image files. I took the primary image file and used it to image a 16GB CF card. I then popped it into the back of the Amiga 4000, turned it on, and…
It wasn’t working properly. The Amiga crashed on bootup. It was fine if I held down the right mouse button to disable the RTG (ReTargetable Graphics) output of the ZZ9000. Which means something is up with the RTG. Also, the mouse vertical movement wasn’t working. More issues to fix.
I figured the RTG was due to the Buster chip, I removed that and gave it another clean, I likely missed a grubby pin from the original corrosion. For the mouse, the left input pull-up resistor had a broken trace from the chip that converts the inputs to a serial stream.
This was a simple patch wire to fix, and luckily, I did not have to remove the board to do it.
Let’s try again.
Bingo! I now have a working Amiga 4000 with a 50MHz 68060, 388MB RAM and a very fast graphics card.
An epilogue to this repair work. Jools went to a friend of Stoo and me. Jops is actually staying with me. This is going to be my main Amiga 4000 going forward, which is why I put all the upgrades in it, whilst preserving the motherboard as much as I could.
The only minor thing I want to do to Jops is add an audio cable from the CD drive to the motherboard. I have run out of such cables, but I have some on the way.
Jools will be coming back to me in February 2025 to finish off the remaining work (new SIMM sockets, new joystick/mouse ports, new U311). In the meantime, I need to backup the original hard drives for the machines and see if there is anything interesting on them.
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That be quiet power supply is not available in the US. My 4000 has a UK power supply. I’d love to exchange for a 60 Hz American PSU so I don’t have to worry about 50 to 60 Hz conversion, etc. but why mess with it if it’s working?
The "bequiet!" brand may not be available, but any SFX power supply would work. If your PSU is working, there is no need to change it. I changed it in the first Amiga 4000 because the PSU was dead. This Amiga 4000 the original PSU would have needed a lot of work to restore and make safe.