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| Mac 7200 Commodore |
| Written by Daryl | |||||
| Friday, 01 September 2006 | |||||
This box has had a very interesting history. It was discovered in an alleyway beside a laundromat near Waterloo, Ontario several years ago. There were no innards, monitor or baseplate, just the empty case & keyboard.... although it seemed the previous owner had been doing some strange mods of his own, as there was already a custom front panel with various switches and wires hanging out, and some schematics drawn in pencil on the inside of the case. This Commodore Pet shell briefly served as a stand-alone Pong console - the guts of a vintage Telstar Pong unit were installed, and holes drilled on either side of the keyboard for each player’s paddle knob to mount. My roommate’s dad had a nice wood shop, and made a heavy wooden base for the unit - thanks Fred! Part One: Semi-Functional FTP/Print Server (2004)
I had a bunch of Mac parts lying around and wanted to make use of this awesome Pet shell to hold some sort of working computer. System requirements were not terribly high. All I really wanted was OS 8 and an ethernet port for networking. I found a Power Mac 7200 (circa 1995) at a garage sale for $20. You can run up to OS 9.1 on this model, but I decided to stick with 8.6 as it still allowed me to use an old serial Connectix Quickcam (OS 8 only) and I really didn’t need any of the OS9 features. CPU was a blazing 75MHz, and I installed a massive 1.2 GB hard drive – that’s over a THOUSAND megeabytes!
After some careful measuring and positioning, I found an arrangement that would allow the power supply, hard drive and logicboard to fit inside without getting in the way of each other. The power supply was mounting using some crudely fashioned metal brackets, so it more “hangs” than is firmly screwed down, but that’s fine for my purposes. I decided to leave the large clamp inside as it wasn’t bothering anything else and did do a find job of holding the top monitor section on. At the time I didn’t need to put any PCI cards in there, but there was supposed to be enough space to insert at least one – as I found out later, there would need to be some further hacking to allow this. I happened to have a 9” green monochrome monitor (it was, in fact, an early Apple monitor, but I am not sure which model) that, when removed from its own casing, fit very well into the top of the housing. There were two existing brackets on the back of the monitor hood. By carefully bending a metal support beam in two places, I was able to support the internal monitor frame and avoided having to drill any additional holes in the Pet case. Dimensions were a bit too big to fit the back panel of the Pet back on, so the monitor components do hang out a bit, which is probably better for airflow anyway. You just need to be careful poking around back there when it’s turned on, as there is no shielding or protective guards whatsoever. The next issue with the video signal. Now I had to convert from old-style RGB Mac video to analog B&W. I found a website detailing how to hack the video port by splicing three pins together (basically isolating one of the R-G-B signals and tricking the computer into thinking a composite monitor had been connected). However, due to the lack of shielding on the monitor and interference, the image was very jittery and difficult to read. Hard drive activity made the image flicker worse. At this point, I had planned to use the Pet Mac primarily for an FTP / Laserwriter server, so being able to see the screen clearly was not really an issue, as it would usually be turned off. I had it up and running for about 6 months, and then started having problems with the video connection. It kept shorting out and melting the video signal wire. Part Two: Funky Working Mac! (2006) At this point, the computer still had the original Commodore keyboard. Although I got a kick out of those crazy ASCII graphics below the letters, it was completely useless and a regular Mac keyboard still had to be plugged in the back to type. Without the keyboard power button, it was also very difficult to turn the computer on, as you had to remove the front switch panel, reach down inside to poke the motherboard main power switch with the tip of your finger. 
I had grand visions of replacing the original keyboard with a proper Mac keyboard, but because of the size, none of the “extended” keyboards would fit - I needed to find a rare Mac “compact” keyboard, without function keys or the separate arrow key block. I did come across one other Commodore Pet case mod recently where the dude had actually managed to keep the original keyboard intact and get it to work with the new PC motherboard, but I wasn’t really up for an engineering task of that level. I looked for months locally for a compact keyboard (I’m sure I have thrown out at least two of these in years previous) and finally ended up getting annoyed and ordered one off eBay for about $30 ($20 of which was shipping). Some tedious enlarging of the keyboard cutout and grinding with the Dremel tool, and it finally fit! There were 6 raised screw mounts getting in the way, and I was using three of them to screw the wooden base to the rest of the computer shell. The other three were cut off, and notches had to be cut out of the edge of the Mac keyboard to allow it to fit into place. It had to be very exactly positioned, or the top row of keys would bind and stay down when depressed. It still looked kinda lame with the beige keys, so I spray painted the entire thing flat black to match the rest of the case. One more problem: I didn’t have an extra Apple ADB cable to connect the keyboard. Okay, knowing that ADB and S-VHS are basically the same cable, I just grabbed one from the dollar store. Unfortunately, after getting it all hooked up and the case all firmly reassembled, I went to test it and found out much to my annoyance by testing the continuity that one of the pins in this particular cheap cable wasn’t even connected. The monochrome monitor is not quite as firmly mounted as I would like, so every time the computer is flipped over to have the base unscrewed, the monitor slips and has to be painstakingly repositioned. I found a higher-quality S-VHS / keyboard cable, and now all is working well. The mouse plugs in the opposite side of the keyboard and pokes out on the right side of the computer. 
Back to the video again: in this next reincarnation of the Pet Mac, I wanted to have a bit more use from the monitor (i.e, remotely playing my iTunes library from my main computer’s hard drive), and the wavy blurry signal wasn’t going to cut it. I suppose I could have rigged up a new colour LCD panel, but the ancient green glow just makes the whole project that much more authentic-looking. I had an old 8MB ATI video card with composite in/outs that would work great for this rig (and the original layout should have allowed for at least one PCI card to be installed) - but I soon discovered the video card was too long and wouldn’t fit under the hard drive. So the HD had to be removed and remounted at a different location. In order to use some of the built-in screw mounts, the hard drive was reattached at this odd angle - whatever fits! Now some more carving and hacking away with the Dremel to create a channel in the edge of the casing for the top of the video card to sit on. I must note at this point that 25 year old burning Commodore Pet plastic is perhaps one of the foulest odors I have ever come across... and I’ve lived with golfers! When it is on, the monitor image (Apple desktop) is slightly shifted to the left of the screen but not enough that it would be an issue. The front panel has two toggle switches, two push-button switches, and two RCA jacks – all installed from the previous owner of the case. I have the monitor power on one toggle switch, and the main Mac power on the other. To start up the Mac, you just quickly flick the one toggle up and down. 
Future Plans Ideally, I’d like to fit some sort of trackball in there instead of having a mouse hanging out, but space is so tight in there (less than 1/2” between the edge of the Mac keyboard and the edge of the protruding ram chips) that I don’t know if it would be possible. In theory, I could also squeeze in a CD drive to load from the side of the case, although I really can’t see much use for it. Anything I need to install on there can be transferred by ethernet. It might be possible to stick a more recent logicboard in there, but because of the low height under the keyboard it would need to be a processor with a very low heatsink, usually the highest part of the board. I may replace the front plexi switch panel with a cleaner one that doesn’t have all those extra holes and switches I’m not using. At the moment I am quite content with this funky beast and it has become quite the conversation piece. Most people don’t recognize the Commodore Pet case and just know that it looks old and cool. They’re amazed to see that you can actually get “The Internet” on such a 9” green screen. 
 
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