Finishing up the Archimedes

So I have made quite a lot of progress since my last post.

I replaced the damaged capacitor on the mainboard.
I cleaned the case a bit further to eliminate some corrosion I missed the first time.
I replaced the dead cooling fan. (I need to modify this fan as it’s way too loud currently. Time for a resistor in series I think)
I made a replacement backplate, so I no longer have a gaping hole in the back.

After all that I fired it up. Unfortunately the internal MFM hard disk is toast. Initially the floppy drive also failed.

As an aside, the process I went through to write out the floppy disk image I used is as follows:

1. Get a PC with both a “real” floppy drive controller, floppy drive and a suitably old OS. (I used Windows XP as it doesn’t care about driver signing)
2. Get a double density floppy disk. I have exactly three. Hope none of them ever die, as they’re getting stupidly expensive, and I am recycling what I have to bootstrap various systems.
3. Find a suitable disk image. I initially grabbed one I was unable to write out. Turns out it was more like an archive designed to be copied to a hard disk.
4. Install OmniFlop. It’s a great piece of software capable of writing out quite a few different formats.
5. Replace the floppy driver in your windows install with the one from OmniFlop.
6. Open the disk image from OmniFlop and write it to your floppy disk.

After all the work, my floppy disk didn’t work and I determined my floppy drive wasn’t even spinning, despite making all the “right” noises.

At this point I remembered I had a Gotek in with my Amiga “bits” (I have an Amiga 1200. It just doesn’t yet have a case). Time to pull it out and pre-use it for the Archie. I’ll replace it later. (I currently need an additional FOUR Gotek drives. One for the CPC 464, One for each of the Atari STᴇ systems, one for the Amiga). It already had a Rotary encoder and an OLED (Crap! I’ll need another 4 of those too!) as well as the speaker piezo.

I ran a long molex to floppy power lead and a long 34 pin IDC cable out of the front where the floppy drive is supposed to go and ran it to the Gotek. Almost immediately I had booted my first software, and what better to run than a classic?

One thing that didn’t work, and doesn’t work is the MIDI card that came with the system. It locks the system up with a cryptic error. (Error:AddressException:Address exception at &%0 (Error Number &80000003)) and I have not been able to identify what exactly the issue is. The StarDot forums suspect it’s either a bad chip, a bad ROM or just a plain incompatible Podule. Unfortunately no one seems to have the ROM anywhere so I can’t eliminate that.

Oh well. So much for my plan to run an MT32 emulator and have MIDI coming out of it.

I decided to clean and lube the floppy drive, and much to my surprise, it now works! I just cleaned with isopropanol and lubed with lithium grease. Nothing to fancy, but it did confirm my disk burning process was fine.

This put me in a dilemma. I want to use a Gotek, but I also want to use the floppy drive. The system does support two drives, but there’s only one floppy drive hole, and it’s non standard. After debating cutting a hole in the front bezel (Something I really didn’t want to do) I realised the system is designed with modules in the back. Why not mount the gotek in the podule bay?

My initial tack was going to be to design something and have it 3D printed. I even investigated alternative software to OpenScad but decided there was an alternative. My backplate is made out of some cheap Aluminium extrusion I found in a discard pile, so I had no emotional attachment to it. I had painted it to match the rest of the system, but that was it. I decided I could, if I was careful, cut suitable holes in the plate and mount the Gotek directly. I even had spare Gotek cases I could use and abuse. What did I have to lose?
I even had some cunning plans for the encoder and OLED.

I carefully scribed the hole for the USB, the LED and the two buttons, and then carefully scribed them AGAIN on the correct side. (Measure twice, cut one and all that gumph).
Some punching, drilling, filing and general cleanup and I had the holes transferred from the Gotek case to the plate. Now for the first tricky bit.
I then used a fine saw and a rotary tool to cut the fascia off the Gotek case. It added too much thickness to the overall project. Then I carefully epoxied the bottom part of the gotek case to the plate and waited for it to dry. This allowed me to mount the PCB in place with proper standoffs. Once it was dry I did a test fit. A little more filing to make the holes slightly wider and it fitted quite nicely. Onto the second tricky bit.

I wanted the OLED and Rotary encoder to be a separate module I could plug into the back of the unit so I sat down with pen and paper and designed a simple setup. It consisted of a 8 way Dupont connector with a hole masked off as a polarity indicator. (I used a toothpick to mask off the hole). This then connected to 7 points on the Gotek board. On the other end I got some simple pin header, cut it down to 8 pins, pulled the matching pin to match the dupont connector, and soldered it to a piece of veroboard for mechanical strength. I then soldered on a length of cable, securing it to the veroboard with a cable tie for mechanical strength. (Once everything was tested, I then put a piece of glue filled heatshrink over the whole end to make quite a practical connector.)

At this point I decided “practical prototype today” trumped “final product that may not work in a week”, so I hunted through my parts bin for the first vaguely suitable container I could find. Turns out it was an old spice container that I’d already used for an electronics project several years ago. Out came the IR LEDs. In went the OLED and Rotary encoder.

Another wander around found a generic knock off child’s construction block that made it easy to secure the dupont connector to the backplate. I then just cut a small rectangle out of the top of the plate, glued the block to the plate and then glued the dupont connector to the plate and the block. It’s surprisingly rigid.

The first time I fired it up, the OLED didn’t work. Turns out I had inverted the wiring on the dupont connector I was using to connect on the inside to the Gotek. Thankfully it’s easy to remove and rewire them. I also had the OLED in upside down. It was only held in with electrical tape, so I was able to rotate it without any issues.

I’m very happy with the way it all looks.

The next step (for now) is to get some more 34 way IDC connectors and build the custom cable needed to support two drives. Once that’s in I’ll probably just enjoy the system for a while. Down the road I’ll get an IDE Podule, but not yet. I have already spend all my monies for this month. Next month I’ll be getting a cartridge for my Atari 800xl.