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Buying old Acorn kit

I've been getting a few emails about buying old Acorn machines for playing those old classic games that made school days just about bearable. So, here's a quick guide about where to buy and what to look for. The focus of this page is mainly early RISC OS machines, with some BBC Micro era stuff; brand new RISC OS machines can still be bought, but that's at least another page in itself.

Where to buy

There are a number of places to go on the 'Net, although before I launch into that I want to recommend going to one of the RISC OS shows. You can get base units of old machines like A300 and 400 series machines for about a fiver, later machines for a bit more, spare parts and cool toys from the charity stall and so on. Okay, so you have to pay petrol to drive there and then entrance money, but you get to see the machines, know that they're in perfect working order, take your pick from a number of options, avoid potential damage when getting machines by mail, ask questions of knowledgeable people and support RISC OS companies (or at least take old stock off their hands so they don't have to pack it up and take it home with them).

Next I recommend talking to CJE Micros. Although they don't often list second hand machines on their website they have a reputation for having everything in stock, and sure enough when I checked they have things as far back as the BBC Micro and Electron available. The guys there are award-winningly knowledgeable so should be able to answer any questions you have. You can also try Future Computers who list second hand RiscPCs and A7000s on their site, and had an A4 laptop last time I looked; ITC UK claim to have second hand machines, and although I can't see any listed on their site I do know that they are a good source for spare parts either new or refurbished. A quick Google shows AJS Computers have some Archimedes for sale at around 30 quid, and Octopus Systems have some second hand parts.

If you don't want to go though dealers then you can source bargains yourself, although you have less of a guarantee that things will reach you in good working order. There are two main options here; the newsgroups, or eBay. The comp.sys.acorn.* hierarchy of newsgroups get postings offering systems for sale all the time, especially comp.sys.acorn.hardware. These are likely to be a bit more expensive as the people on the newsgroups are a little more likely to either know what they're talking about or prize their possessions more highly, but you are fairly likely to get a full system in proper working order, including monitors, mice, software and so on. You should also look out for people giving stuff away, but usually it'll be some school offloading a whole skipload of stuff which you have to pick up yourself in its entirety. eBay's Acorn or BBC Micro sections (both listed under Vintage in the Computers and Gaming section) can offer some real bargains, but you have to be a little more careful. I've bought maybe five items off eBay and not had any problems, but quite apart from the possibility of fraud there's the time it takes to conclude the transaction (after the auction ends which takes time in itself it could be several days until the cheque clears and the seller manages to box up and send the goods), plus the cost of postage. It's also too easy to buy stuff from eBay, so try not to allow it to become addictive ;) Set an upper limit for yourself and stick to it - if things get too rich for your wallet back off. Oh, and try not to bid right away, wait until the auction is about to end if you can as it means people are less likely to bid against you. Finally, it's easy to get partial systems off eBay, so you'll have to source the other parts to complete the system. Which leads us to...

What to look out for

Buying anything second hand is a risk, and most things have known potential problems to look out for - like woodworm in wooden furniture or the electrics in a Land Rover. Computers are no exception, so I've tried to dredge a few tips from the depths of my memory.

A lot of systems come without (working) mice. This is pretty normal given the amount of hammer they take in the course of normal usage. Try cleaning the mouse first. There are two screws underneath most Acorn mice, take these off and the bottom opens on a kind of tab/hinge arrangement, and look for the rollers on which the ball of the mouse rests. This might be caked in grime, use the flat blade of a screwdriver or a sharp flat knife to scrape this away. Don't drop this cruft on your work surface as the mouse will probably end up picking it up again! :) If this doesn't work, your can try sourcing new ones. I think the original Acorn mouse was actually a Sun mk1 mouse, but that's probably not much help. RISC OS dealers (such as the ones listed above) will probably be able to source new or used replacements, or if you want to go with cool/PC standard stuff you can get converters to make them work on Acorn machines. A PS2 mouse can be used on Acorn hardware with something like the PS2Mouse which is sold by Stuart Tyrrell, and USB cards such as those made by Simtec have generic and some specific USB mouse drivers included. I think Castle also sell both of these options but I haven't played with examples. Anyway, one of my RiscPCs has an optical scroll mouse installed, and the other (sometimes) has a wireless mouse. Note that A7000 machines use PS2 mice as standard.

RiscPCs and A7000s use PS2 keyboards as standard, so you can get pretty much any PC keyboard so long as it's PS2 or dual PS2/USB. A USB card will allow you to use USB keyboards too. Older machines (e.g. the A310) have different keyboards - they have PS2 type adapters (I've used a PS2 cable extension so I know that much) but I'm told aren't actually PS2. Seeing as they have the mouse plugging in to the back of the keyboard I guess this must be true although I don't have one to hand to experiment on. Hit the dealers, look out for people getting rid of otherwise broken or useless systems, or ask around on the newsgroups for replacements.

Hard drives
Older Acorn hardware (A400 series) had ST506 hard drives - good luck finding a replacement. Better to just ditch that, get an IDE (or SCSI) interface and buy something slightly more up-to-date. Note that older machines are restricted to a maximum of 512MB per drive, although if you have a third party interface you can usually get up to 4 partitions on a drive - so a 2GB drive can be used in full, just split four ways. Some machines have in-built Acorn IDE interfaces (A5000, RiscPC) and can't be partitioned without third party software. Small drives like this are almost impossible to get from standard PC part retailers, so go to the RISC OS dealers, newsgroups, auction sites etc. Big, modern drives probably won't work on older machines, although you don't have to get something exactly 512MB - anything sub-8GB should work, you'll just lose anything above 512MB (or 2GB using partitioning). A waste, but maybe necessary if you can't find anything more suitable.

The RiscPC range can have bigger drives, but the Large File Allocation Unit (LFAU) can make a nonsense of this. The LFAU is basically the minimum amount of space on disc a (bit of a) file will take: the smaller the disc, the smaller LFAU, the smaller the amount of space needed to store the file. Cut to the chase, I had a 4GB drive in a RiscPC and in tests it took more than twice the amount of room to store some files than the 2GB it was supposed to replace, which meant it stored less data than the 2GB drive! The best option is to upgrade your RiscPC to RISC OS 4, which not only eases the LFAU problem but offers things like very large hard drive capability and fixes restrictions on filename size and the number of files allowed in a directory. Currently with RISC OS 4 you can get any PC boxshifter IDE hard drive and it'll work - I have one RiscPC with a 40GB drive and another with a 30GB drive, as they were the best deal at the time they were bought. As I'm writing this 60-80 GB drives work out at as the best value for money. Beware though as RISC OS 4 stores the drive's map in memory which can mean 1-2MB of memory being eaten up.

Acorn IDE interfaces only have one socket, so only take two devices - usually a hard drive and a CD ROM drive. Third party upgrades can solve a multitude of problems like more sockets, faster speeds and compatible with more drives/devices, but does your power supply have enough wires coming out of it to power these devices? Y-splitters, external boxes with their own power or a new (additional?) power supply might be necessary.

The A310 was the worse machine for upgrading the memory - you had to desolder a load of chips and solder in a new board, plus replace the MEMC (memory controller) chip with an MEMC1a. This took a trained college technician a whole afternoon upgrading my first Archimedes, and it didn't work straight away so there was a tense half hour checking the connections, so if you want to upgrade best send your machines away to a dealer. The maximum is 4MB, or 16MB with a non-standard dual MEMC1a configuration; as the A310 only had 1MB of memory (and the A305 only 512KB!) you're probably going to need to upgrade unless it's already done, so look for a pre-upgraded one. A400 series machines were more easily upgradable, and some machines came with the 4MB maximum by default - check when buying which one you're getting. A3000s have 1MB on board but a separate upgrade slot for up to 4MB, although I think the original 1MB is "lost" so you don't get 5MB. An A540 could IIRC have much more memory using upgrade slots (16MB?), but it's not until the RiscPC/A7000 that you could use proper PC RAM. This is in the form of 72pin non-parity SIMMs, which can just about still be bought through regular channels (EDO RAM will usually work, but check that returns policy). RISC OS dealers can source these for a little bit more money, but at least they check compatibility for you.

Older Acorn machines don't (or indeed can't) use standard VGA monitors as they output Acorn's weird rectangular pixel low resolution graphics. The A300 and 400 series, along with the A3000, are the ones to watch out for. Best to try getting a monitor from a dealer or getting an old bust one repaired. I think anything from the A5000 onwards has a standard VGA monitor output. The A5000 monitor could overheat though!

Floppy drives
Earlier RISC OS machines used low density floppy drives, so go through the usually dealer/spares channels. Later machines (A5000 onwards) have standard high density floppy drives, although I don't have much experience replacing these with PC parts - it should work, but don't hold me to that.

CD ROM drives
Seek advice from a dealer or the newsgroups for older machines, but I have experience with fitting or replacing drives on RiscPCs and A7000s. I bought about five drives until I could find one that works - strangely Creative Labs drives seem to work, despite being from makers of oh-so-PC Soundblaster cards. I've fitted an old 8x and a spanking new 52x Creative drive to RiscPCs without problems. Some DVD drives may work, but there's currently no DVD movie players for RISC OS. Getting an IDE card will give better speed and maybe a better range of compatibility for CD/DVD drives, and pretty much essential for CD writers.

Hitting the auctions shows a distinct lack of the brick-like external power supplies for Electrons, so watch out. They sometimes get auctioned off on their own though. I never had a problem with the PSU, but as there's no on/off switch either on the machine itself or the PSU there's the chance that you'll switch off by pulling out the PSU plug where it goes in to the computer. This can cause damage to the circuit board inside, although when I did this years ago it just cracked the solder which a quick re-heating with a soldering iron fixed in a jiffy.

BBC Masters
The BBC Master series had a problem early on with exploding backup batteries, but chances are that anything you're buying now will have passed that test long ago. The main worry I can think of is a bust keyboard, which seems to have been a bit iffy on the Master. The Master was quite easy to reconfigure into foreign character sets and fonts (a neat trick at college was to set them up to output Greek, then look like a genius "fixing" the problem with a few *commands) which could also occur if the battery is duff and so the CMOS settings are corrupt, but I've got a BBC Master which won't produce output from certain keys which is a definite hardware fault.

The main worry with the RiscPC is the power supply. One of the components seems to have been the wrong one for its particular job and liable to blow, stopping the PSU working although usually without causing too much collateral damage (I saw this happen at the show the RiscPC was first shown at). The beefier power supply that came with the second slice upgrade doesn't suffer from the same problem, and can power four hard drives instead of just two. I would expect that reconditioned PSUs would have already blown and been fixed with a more appropriate part, but new or second hand these puppies are expensive - find someone who can fix the old one if possible.

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