Commodore Amiga A1200 Tower Project.
Here are a few notes and pictures following the ongoing conversion of an Amiga A1200 into a tower based system, using a Commodore PC gaming case. I'll add updates as the build progresses.
- Existing A1200 configuration.
- Objective.
- Requirements.
- Parts and materials.
Part 1. Installing the mainboard and new rear panel.
Part 2. Fixing the Lyra 2 & Fast ATA mk iii fitting problem.
Part 3. Converting the PC Floppy and Media Card RW Combo Drive. Added August 16 2014
Resources:
Rear Panel drawings: - Links to the photos were broken due to a hosting closure so I have re-uploaded all photos and drawings to Amibay and relinked them within the thread.
JPEG format .jpg (233KB) For some reason these JPGs do not render well in a web browser, but look better downloaded and opened in Photoshop, Photopaint etc.
Case Rear Panel
Case Rear Pane 2 (Includes dimensions for PCI cutout) Added June 2nd 2012.
A1200_Rev1B_fixing_centres.jpg(Includes dimensions for fixing centres) Added May 14th 2014
Corel Draw format. .cdr (39.8KB). This version is currently lost as of August 2019.
Autocad format .dxf (3.4MB)
Existing A1200 Configuration.
- Standard UK assembled Commodore Amiga A1200.
- Revision 1B "CHANNEL Z" main board.
- V3.0 (39.106) ROMs.
- 68020 Processor.
- 80MB Tidbit Western Digital Hard Disk Drive.
- Original commodore internal floppy disk drive DF0:
- Workbench 3.0 Operating System.
- Micirobotics MBX1200z 4MB + 68881 FPU expansion card.
- Archos Overdrive PCMCIA CDROM drive.
- Philips CM 8833 Mk II Monitor.
Objective.
Remove the internal components from an Amiga A1200 and install them into a Commodore PC Gaming case with additional upgrades.
Requirements.
Hardware.
- Remove the existing backplane of the Commodore tower case.
- Fabricate a new backplane to accept A1200 connectors and PCI slots.
- Reposition the main board mounting jack posts.
- Reconfigure the A1200 LEDs to work with the case LEDs.
- Install a micro ATX power supply.
- Install a chassis exhaust fan.
- Install 3.1 ROMs.
- Install an accelerator card + MMU, 68882 FPU, SCSI kit, + memory.
- Install PCI expansion upgrade.
- Install USB capability.
- Install PCI cards.
- Install keyboard adaptor.
- Install DVD ROM drive.
- Install a combined floppy drive and multi card reader; converted PC unit.
Software.
- Install Workbench OS Version 3.9. + Boingbags.
- Any patches required for stability/compatibility.
- Install Proprietary software for any HW upgrades.
Parts and materials. (required for conversion and upgrade).
- 1 x Commodore PC gaming case.
- 1 x 500mm x 250mm x 1.5mm aluminium sheet/plate.
- 1 x "Be-Quiet" SFX 350Watt Micro ATX Power Supply Unit.
- 1 x 80mm chassis exhaust fan.
- 1 x Borrowed PC PCI rack.
- 1 x Mediator PCI 1200 TX expansion card.
- 1 x Phase 5 Blizzard 1230 Mk IV @ 50 MHz. +SCSI kit.
- 1 x Subway USB module.
- 1 x Lyra 2 keyboard module.
- 1 x Elbox Fast ATA 1200 mk III IDE Controller.
- 1 x ATI Radeon 9250 256MB Graphics Card.
- 1 x Linksys Etherfast LNE100TX 10/100 Ethernet card. V4.1.
Part 1. Installing the mainboard and new rear panel.
Here are a couple of pics of the Commodore gaming case new and just unboxed.
Front Open View:
3 Quarter front view:
3 quarter rear view:
Here's one, of the huge side panel mounted intake fan:
An inside view showing the rear panel to remove:
Checking the A1200 mainboard will fit:
A closer look at the Blizzard card clearance:
A look at the obstacles hindering the mainboard: There are 6 jack posts and two preformed ATX PSU shelf things to modify. The jackposts were simply unscrewed.
A closer look at the PSU tray:
I didn't get a picture of the little angled spacer after it was squashed but I got one of the shelf after flattening with a pair of tile snappers as they were angled and fitted into that rectangular hole nicely.
Ok, on to the rear panel removal: The panel itself is a seperate piece and was removed by drilling out the securing rivets with a 3mm drill.
I think it was 13 rivets holding the rear panel to the main chassis. Here is the chassis after removal:
The rear panel liberated. This will be used as a template to draw around and give the new rear panel its outline:
Taking a piece of the aluminium sheet I bought, I drew around the old rear panel and cut out the new shape, adding a radius to the top most corners and cutouts near the top on either side to allow the side panel top lips to slide back and fore. The aluminium sheet has a protective white plastic film so was easy to mark onto:
I aligned the mainboard connector flange plates to be on the same plane as the rear most angled part of the motherboard tray (where the new rear panel would cut across; shown by orange arrows). I could then mark, drill and tap the 3 mountings for the mainboard (red arrows) and make a note of the distance of the center line of the mainboard connector ports away from the motherboard panel face.
After cutting out and cleaning the edges of the new panel I offered it up to the chassis and kind of held it in place with the top removable panel. When in place I was able to mark a line where the rear panel and the motherboard tray meet, line "1" in the image. This gave me the reference line which I could measure from to get the A1200 connector center line, shown by line "2". I also marked one of the connector ports fixings to give a reference for how high or low the mainboard would sit against the new panel.
I used the A1200 RF shield(?) to mark out the connector ports:
Another obstacle I found whilst dry fitting the mainboard was a part of the chassis that blocked the A1200 power connector.
The chassis was cut to allow plugging in via the brick type PSU if needed.
With the mainboard fixed in place along with the Mediator PCI 1200 TX and a couple of PCI cards I was able to attach a PCI rack I removed from an old PC case that I had doing nothing.
I had by this time cut out the connector port holes and removed any debris/swarf from the new panel. This allowed me to hold it up to the PCI assembly and mark out where the PCI card hole would be, as in the following pic (shown with a red line). The green hilighted area is an indication of the area to cut out. This was determined after marking the red lines then adding the internal "hole" dimensions.
Here's a view of the panel after roughing out the PCI and connector port holes:
...and a quick dry-fit to check PCI alignment:
I fitted the mainboard to its jackposts and added the rear panel to allow marking out the new microATX PSU and exhaust fan. Had a lot of to-ing and fro-ing here checking measurements against that huge side fan. It made no difference in the end because the fan hits any full width PCI cards. I'll have to source low profile cards if they're made. Luckily the Radeon and network card I have are low profile. Not sure what to do with the sound card yet.
After marking the PSU and exhaust fans on the new panel they were also cut out and everything cleaned up. I also added the fixing holes for the PCI rack.
This one shows the PCI rack fixed with a few rivets:
Checking all the bits fit before painting:
Adding primer. I had some Tamiya model primer left in a can which I used the last of for the panel. It was a rare glorious sunny day and it was nice to get outside to do this step:
After adding the top coat of gloss black. Some car paint I had left over from a guitar modding project for my Nephew (which didn't quite go as planned).
The gloss black is a little too shiny to match the rest of the case so I'd like to add the connector lettering, then spray a top coat of satin or eggshell clear.
Another view:
An inside view, sorry about the angle :
Here's a closeup with dynamic lettering added in photoshop. I would like to find some orange or yellow dry transfers or letraset for this:
Whilst the paint was drying I fiddled with a 3.9 install and the Picasso96 mode thing. Was surprised to get a Workbench at 1920 x 1200 @ 32bit. Apologies for the image quality:
Still loads to do. More to come later when I add all the bits inside the case. I've already hit a big problem. The Lyra 2 keyboard controller and Fast ATA mk III are not physically compatible but I have a plan for that.
Cheers for now,
Ed.
Thanks everyone for the kind comments and enouragement.
Part 2. Fixing the Lyra 2 & Fast ATA mk iii fitting problem.
Anyone who's bought a Lyra 2 keyboard adaptor and fast ata mk iii board knows they are incompatible. They physically will not fit together in an Amiga 1200 as the Lyra 2 clips over the keyboard controller IC and pushes up the Fast ATA. I realised the problem after buying both and was initially disappointed.
Here's a pic of the Lyra 2 with its chunky PLCC socket:
...and the solder side:
So I thought I could extend the contacts from the A1200 keyboard controller out to the Lyra2 a few cm's away. I initially thought about soldering wires directly onto the pins of the controller but had second thoughts because they're just too small for my soldering skills and I don't really want to alter the mainboard in any way, if possible.
At the Lyra 2 end of the extension I worked out there are only 5 connections used and added 5 wires onto the solder side. I haven't soldered anything in ages so pls excuse my effort, I applied too much heat to the insulation:
At the controller end I decided to use an SMT PLCC connector upside-down. It's much slimmer than the one on the Lyra 2, about half the height and fits nicely under the Fast ATA mk iii. I had to cut out the center plastic portion because the socket was still a bit too high to clip into place. This unfortunately broke the side of the PLCC socket (expletive!!!!). Managed to repair it with some araldite and a plastic strip as a bandaid.
24 hours later the araldite was secure enough and I soldered the other end of the 5 wires onto the respective SMT connections. I've also cut out the adjacent pins near the wires to try to reduce the possibility of pins touching. I'd like to have added some heat shrink to these but I have none:
To insulate the pins further I've applied some Kabuki tape, (used for paint masking in model making):
...and here's the SMT socket fitted upside-down on top of the keyboard controller:
At first it didn't work so I ended up having to tease out the connectors on the SMT socket. Seems to work ok for now.
Added the Letraset connector port markings today. Doesn't look too bad (from a distance) I need to cover the letters with a laquer or clear coat to protect them. I didn't apply the names word for word, no need really.
Part 3. (August 2014) Converting the PC Floppy and Media Card RW Combo Drive.
It's been a long time since I did anything on this project because I thought I had damaged the Mediator board. But I recently discovered it was ok and this has rekindled my interest in the tower.
The past couple of days I've been looking at the combined floppy and card reader drive I installed in the tower and whether it could be converted from its PC spec to work with an Amiga.
Details:
Made by a company called YE-Data
Label 1. YD-702J-6637J F (image below)
Label 2. D33253 (image below)
Purchased from Scan.co.uk (unfortunately no longer available on their web site).
I managed to find a spec sheet for the floppy drive and after studying the pinouts it appeared (at least to me) that I just needed to cut 3 traces and solder 4 new wires to the interface board that sits between the Floppy connector cable and the drive mechanism.
The drive mechanism itself connects to the interface board via a 26 way ribbon cable and FFC headers.
Here's the procedure for converting the drive.
1. Unclip the FFC header on the interconnect board.
2. Undo 4 cross-head screws, 2 each side to release the floppy mechanism from the main housing. Care must be taken when removing the unit as it is very delicate, unlike most floppy drives. There was some slight distortion in this unit which proved troublesome when it was all put back together, more on this later.
Unit and housing separated. The USB Card reader can be seen now and is a completely separate board.
3. Undo the 2 screws holding the interface board to main housing. One has been removed already.
4. Flip the board over and make the following modifications indicated in the photo below.
- Cut the 3 traces marked by red arrows.
- Add wires between the pins marked with the same letters; A to A, B to B, C to C and D to D.
I can provide more detail on the pinouts if anyone needs it, please let me know.
Here's a photo with the new wires added.
5. Reassemble the unit in reverse order. Connect up and hopefully it should all be ok.
That's it, just 3 traces to cut and 4 wires to add. The hard part was working out the pinout mapping. I also had mechanical issues with the drive where it was slightly warped and this caused DF0: BAD and DF0: Uninitialized errors. If I slightly flexed the unit I could get Workbench to recognise the disks so I actually took it apart again and checked everything was square and straight. I had to make some slight mechanical corrections to the frame which slides the floppy disk in and out. It was only a very minute distortion but enough to confuse the read-heads. I have been testing the read/write functions of the disk and all seems to be ok so far checking against other external drives that I have.
Further ideas:
I noticed on the 26 way interface on the floppy mechanism there are two additional pin signals not used by the Amiga. These are "HD(High:HD)" and "Mode Select" according to the spec sheet. I am wondering if these could be used to enable writing HD 1.76MB disks if I could somehow get the Amiga to recognise the signals. I think this is beyond my knowledge of the Amiga though, but if anyone has any ideas of how to attempt it and would like to share that would be great.
Cheers for now.
Here's a picture of the floppy drive pinout assignments in case anyone finds them useful.
Last edited: