Saturday, June 03, 2017

Amiga A1200 in a Micronik Tower

This post is primarily to show my pride and joy - that I am now looking to sell. I am an Amiga nut and always have been but sometimes real life takes precedence...

UPDATE 4th July 2017 -

After failing to attract any interest on the Facebook page or eBay as a complete unit, I dismantled this and sold it piece by piece. I made more money that way but I was disappointed that the complete system could not go to someone who would appreciate it as it was.  Cest la vie.


On with the show.

When the A1200 was launched it was a capable machine but, even in 1992, the PC  was starting it's rise as more than a boring green screen spreadsheet generator. The expandability of the A1200 was a bit limited, being restricted to a (somewhat pointless) 16 bit pcmcia slot, an ide interface and a trapdoor expansion slot. But the trapdoor does allow access to all of the input/output lines and is essentially a Zorro slot with AutoConfig. 

Just as an aside, AutoConfig allowed pretty much any expansion to be hitched up to the Amiga and it would just work. Windows would not get this equivalent functionality until 1995 but the Amiga had it almost from day 1 (c.1986!).

I digress.

By shoving the A1200 into a tower case, this allows more expansions to be added via additional boards known as Mediator boards. These connect to the expansion slot and act as an interface to standard PC PCI or Amiga A2000 cards such as graphics cards or sound cards or even ethernet cards. It was for this purpose that I bought the Micronik tower. Sadly, these 'Mediator' boards are even more rare than rocking horse droppings (and more expensive).

Tower Loveliness

This is a Micronik tower which is built from plastic modules that fit together around a minimal metal frame. It includes slots on the back for accommodating any installed PCI or Zorro type cards (additional Mediator board required to install PCI or Zorro cards). It has a Rev 1A A1200 motherboard installed. This board was re-capped in 2014 (see here) and the audio fix was applied at the same time. For more info on the audio fix see RetroGameModz youtube video here.

Rev 1A - Channel Z

There is a single floppy disk installed although there are two slots which should allow a second unit to be included if necessary (you'd need to find another plastic frame to accommodate this). I currently have a standard external floppy plugged into the socket on the back and the unit just rests on the top without any problem.

There are three bays for CD-ROMs etc and there is a SCSI CD-ROM installed.

CD-ROM's Butt

The power supply is 200W which is more than enough to drive whats currently installed and should be ample for most Mediator boards with a couple of cards installed.


There is no Mediator board included with the tower.

There is an ACT Apollo 1220 accelerator board installed with a full 68020 at 25Mhz with 4Mb of RAM. This is the maximum this particular board can handle but it does mean it stays PCMCIA friendly and still does a pretty good job of zipping things along.

68020 Accelerator
Cowabunga indeed...

This particular case also comes with a couple of caveats. The previous, previous owner had cut off the plastic plug that linked the power supply into the keyboard adaptor board. The previous owner (who I bought this from) just used a standard Amiga power supply brick to drive the motherboard. I did try to find a replacement connector but it proved harder than I expected. To allow the whole system to be switched on from one button, i.e. the red button on the front, I soldered short cable lengths to the connector in the case (see photos), and then linked to the power supply by a simple connector block. (I should point out that I had not intended to sell this, hence the slightly unorthodox solution.) Then I inserted the power port adaptor at the base of the rear of the tower. The next owner might have more luck in finding the right internal connector. Either way, what I did is easily reversible.

Power Connector Block

Wires Soldered to Power Connector
Power connector adaptor - the whole reason I soldered the wires internally!

The top panel of the case is a simple loose fit on top. Despite having obtained a PDF of the case construction instructions it's not clear if this is the way it's supposed to be. I added two small screws to stop the 'lid' from being pushed off too easily.

Top Cover
There is a right angle PCMCIA adaptor that allows the PCMCIA connector of the SCSI interface to connect to slot without any problems.

PCMCIA Right Angle Slot

The A1200 keyboard is contained in an external case with a coiled cable that has a PS2 style plug. This also means that it's possible to use any PS2 style keyboard and, to be fair, they do actually work quite well. The existing A1200 keyboard is fully working. Note that the keycaps show some sign of blooming after a couple of attempts at retrobrighting them...

Bloomin' Keys (See what I did there?)

Keyboard underside

To allow the CD and Amiga audio to mix I have a 'home brew' audio mix cable which takes phono cables from the CD audio out and also from the Amiga audio out and combines them into a single pair of standard phono cables. It's not just cut the cables and join them together. It has resistors in series to generate the right impedance. (Audio purists might be outraged by this - but tough.) The levels produced are comparable enough to make playing games like Liberation perfectly OK.

One of the smaller back cover panels is missing but this gives a handy exit point for the CD audio connectors. :)

In summary this is what you get:

A1200 Rev 1A in Micronik tower
A1200 keyboard in external Micronik keyboard case (with cable)
Kickstart 3.1
68020 4Mb Accelerator card
External 3.5 inch floppy drive
Logic 3 SpeedMouse
Power cable
Squirrel PCMCIA SCSI interface
CF IDE adaptor with 4GB card (pre-installed with WB3.1 and WHDLoad)

So there you have it. The price I'm asking for this is shown on the Amiga Facebook group. See you there.