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RiscPC

Two slice RiscPC

Two slice RiscPC
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  RiscPC stripped down

RiscPC stripped down
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While we played with our Archimedes machines, the rest of the world caught up and then overtook Acorn in the technology stakes. The RiscPC was a great leap forward for Acorn, but the 24bit graphics was playing catch-up, not the great revolution 256 colours had been in the days of 4 colour PCs. There were some rather nifty features though, such as two slots that could be used to put the processors - an upgrade is as simple as pulling one card out and putting a new one in (although new processors often require a change in the OS, so you had to change two bloody awkward ROM chips without bending the legs and snapping them), plus the second slot could be taken up with a 486 or 586 (not true Pentium though) processor for PC compatibility.

The case used an innovative design - pop out some pegs (not screws), lift off the lid, and you can add another slice to house all your extra hard drives etc. The cases were made of riot shield plastic for extra toughness. The rest of the machine used fairly standard parts though, so standard SIMM memory could be upgraded easily, and I still get standard PC hard drives, keyboards, CD-ROM drives and monitors to upgrade it (and even mice via a converter) although compatible parts are getting slightly harder to come by.

Pizza Oven
Resurrected Pizza Oven Slice
1600x1200 | 800x600 | 400x300

The upgradability of these machines was taken to extremes for the shows when Acorn was still going strong - known as "rocket ship" having lots of hard drives wasn't enough, and I can remember one with a toaster (which resulted in lots of joke error messages being thrown around on newsgroups for the fictional "ToastFS"), a pizza oven, and yes, even one with a kitchen sink in the top.
 
ARM7 vs StrongARM
ARM7 vs StrongARM
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To the right is a comparison of the ARM7 (bottom) and StrongARM (top) processor cards. Note that not only are the cards the same size, but so are the processors themselves - despite one being a lowly 40Mhz and the other a "blistering" 206Mhz. The difference is one was produced in conjunction with supercomputer boffins Digital. I still have the 200Mhz card in my main machine despite the fact that you can get 300Mhz versions with faster RAM on the same card, and the PC world is currently up to 2Ghz (=~ 2000Mhz) processors. The OS itself (upgraded to RISC OS 4.02) and the software that it has spawned is plenty fast enough for even professional use, although when I'm trying to play MP3 digital music at the same time I'm starting to get a little maxed out.

P5190004
Full 1600x1200, 341KB
Medium 800x600, 60KB
Small 400x300, 18KB

P5190007
Full 1600x1200, 381KB
Medium 800x600, 82KB
Small 400x300, 28KB

Prototype StrongARM card - the header card means it's too big to fit into a standard single slice RiscPC case, it needs a two slice machine

My first RiscPC I got "for free" - apart from the year or so of freelance graphics, game design and DTP work I had to do for a games company first. I was very proud of this machine and used it to great effect. The monitor blew, and I sent it to be repaired under warranty - it took over three months. Then I upgraded it at considerable cost to a second slice so I could get the more powerful (and less likely to fail) power supply that came with it; about a month after I received that I moved to Chichester to work for an ISP and left it at work, and a window open one night the first week I was there, so thieves decided to steal just my computer and a laser printer despite all the other desktop machines and servers in the building. Although the insurance didn't cover people leaving windows open the company kept me on and bought me a new machine (there was some back-payment they owed me for previous freelance work, but it certainly wouldn't have covered the cost of a new machine), and I still have it, still take it to work and bring it home weekends. However, pretty much everything's been upgraded or changed - keyboard, mouse, monitor, memory, hard drive, processor, OS ROMs, power supply, CD ROM drive.

I now have three of these machines, plus enough parts to make a fourth bar a power supply. Two are RISC OS 4, StrongARM machines; I used to carry my work machine home with me every night in case I felt the need to do some programming or web design, and I also set up an MP3 music jukebox with a custom web based front end so it could be controlled from anywhere in the house. It soon became obvious that I should get another machine of a similar spec for home, but the two machines I had there were in various states of brokeness and probably weren't up to the upgrade: both only had 8bit sound, only one of which worked; the other had a broken floppy controller; on one the VRAM slot was dodgy. One - a 30Mhz Arm 6 machine - is still in use as a word processor in the bedroom, in case I can't be bothered to get up. The other is currently in bits decorating my coffee table. The idea is that I'll use it as a template for building a custom case for the home machine/MP3 player/fileserver I eventually built after buying a new motherboard, an old prototype processor, and got the company I worked for to shell out for the OS ROMs after they made me work late.

Case modding

For some time now I've been thinking about case modding - the RiscPC case was innovative at the time, but now it's basically another boring beige box. The first idea was for an A3000 built into a case made of Lego, which would have sorted out a problem with the keyboard bumping up against an upgraded processor. However, that would have needed a lot of Lego. I then tried to modify a Phoebe case to take a RiscPC without dumping the motherboard in sideways, which required cutting away a lot of metal work, and that was going to be replaced with the Lego I'd just bought framing sheets of clear perspex. However, that was proving a lot of effort, and in the mean time I'd built a regular file server, which needed a two slice RiscPC case due to the unorthodox way the prototype StrongARM card was mounted. So plans began for a start-from-scratch clear case with blue LEDs, but I never got round to it because a) it's too much effort (for now) and b) I couldn't find a small replacement for the whacking great ugly RiscPC power supply, so I had to stick with that, and hence the big boring case.

Bad fan! Naughty fan!

However, the fileserver had other ideas. At about 3am it started making a horrendous grinding noise, which can usually be sorted by either slapping it silly or oiling the fan; this time though it wouldn't go away, which is pretty bad for a machine that is switched on all the time. So I switched it off. I looked around for some replacement fans and bought three from Microland's Addons Online - I'd just bought a 1U server from them, and noticed they had a special on some bits and pieces. I bought a straight 80mm fan as a direct replacement, plus a couple of cool transparent fans with flashing LEDs in them - one with blue LEDs, one with green. Obviously the proper replacement sat in the box while I played with the cool ones, and the blue one in particular.

Getting the two slice PSU apart is tricky - two screws at the top, fine, but inside there's some kind of transformer attached to the metal casing which is connected to the PSU main board with extremely short wires, so unhooking the connector was hard work. I then unscrewed the old fan and disconnected it from the power. This was where the second problem comes in. The old fan had a two pin plug, the new has three. The pack I bought came with a converter to power the fan from the same type of plug that powers hard drives, and I had some not being used, but that would have been giving in. I basically ripped the plastic guide off the socket so that I could jam the plug in - the socket ends up as two pins sticking up - and I also cut the cable ties for all the power cables to make it easier to move them out of the way. The fan also comes with a cable with a preset on the end for changing the speed of the fan - at its lowest setting it is only 20db, but as it's summer I cranked it up - and that's a pretty powerful fan! This wire I had coming out with all the power wires, and as the fileserver has no power switch (the plastic broke on another machine, and as the fileserver's on all the time anyway...) the end comes out where the power switch used to be.

Then came the time when I had to put everything back together and... it wouldn't fit. There's a component sticking up from the board that stops the fan from moving all the way down, so the case wouldn't close. Looking at the fan I'd taken out, sure enough one of the corners had been cut off the fan. You would have thought it would have been better to make sure the components all fitted together properly, but no. Anyway, I couldn't find my hacksaw, but did eventually find a spare blade for one, so I took everything apart again, hacked off a corner of the fan, and made it look neater using a sharp knife. I then put everything back together for a second time, and switched it on - nothing. Then I remembered the awkward transformer thing, undid the case, struggled to plug the transformer thing in, and shut the case for the final time. Power on and... success!

Now, this is not an astoundingly useful mod - especially as the fileserver is stuck under a desk, with a full case surrounding the PSU. The new fan works well, and will either be more powerful or much quieter than the old fan even before the horrible grinding sound, but what point were the lights? Well, the lights do come in useful as a little blue light does bleed out of some of the air vents, which means I can see some reflected blue flashes on the wall to check that the machine is working. And if I ever get round to that transparent case...

Update
After experimenting on the fileserver I decided to change the fan on my 1 slice main work machine - it wasn't making a nasty grinding sound, but it was much louder than the fileserver. It's a lot easier on the 1 slice PSUs as there's no tricky transformer clinging to the PSU case, and no component sticking up so there's no need to cut the corner off the fan (even though I'd already done it before opening the case). Plus as there's less wires going out it's easier to get the fan plugged in. The fan with green LEDs in was fitted, but it's much less powerful in the LED and wind departments, and no way of changing the speed, so the quieter running is the only real benefit. Oh, and I did remember to put the cool metal grill in place this time.

 

Click for an MPEG of modified power supply

Click for an MPEG of modified power supply

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