Acorn RISC PC

[alexh]

My first computer was an Acorn Electron in 1982 and while I never owned their successor the Archimedes in the day I always had an affinity for them.

You might have read that I managed to bag an Acorn Archimedes A5000 Alpha a few years ago but the battery damage was beyond my capabilities and it has been stabilised and awaiting my soldering skills to catch up. More recently I bagged an Archimedes A310 which is arguably the first Archimedes mine works but it is running Arthur (RiscOS 1.x) only has 1MB RAM, no HDD controller and while I am interested in upgrading it in the future I was still looking for my Acorn jewel for my collection.

A week or so ago a telephonics engineer replaced the RISC PCs that were operating a telephone and answer machine network in a building and sold off the approx 10 RISC PCs individually. I know these are notorious for battery damage and SMT capacitor leakage and are notoriously to fix if the rot has gone too far, I had too much wine the night they all sold, each one going one after another 2 minutes intervals between, the next going for even more than the last. I bid a low-ball amount in the last 5s of the last one to sell, not expecting to win but I did. Oops.

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It's a MK-III (A1208-000) motherboard which I read are an improvement over the older ones with 16-bit stereo sound but the downside is there is no schematic of this board only earlier ones which can make it more difficult to repair.

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As expected the battery has leaked and needs to come off ASAP and the area nearby neutralising with white vinegar light clean with very soft brush before a bath of deionised water and IPA. It's a lot worse than I had hoped. It's reached the SIMM sockets and there is a layer of white alkali residue over 1/4 of the board.

Again my skills at soldering mean I won't be able to fix this myself in the near future but I am hoping to either bribe the Technician here at Toshiba who assembles much more complicated PCBs than this all the time and/or maybe IanJeffray over at StarDot?

It came with a 200MHz StrongARM processor (and I have bought an 610 to help bring up later) IDE HDD, CD-ROM, 10 base T network card.

[rubber_jonnie]

Ahh, the drunken bidding adventures to be had with eBay :cheers:

Looks decent, but that battery has to go for sure, and quick.

[stephen_usher]

I've seen FAR worse than that.

Vinegar and then de-ionised water for that. People who use Isopropyl alcohol don't know their chemistry. IPA is an organic solvent and the battery contents are inorganic so the IPA does absolutely nothing, similarly it does nothing to clear out the acidic vinegar.

You may be lucky and the corrosion hasn't gone deep.

[rubber_jonnie]

Looking closely at the pic with the battery, it looks like the CMOS/clock IC has been hit quite hard.

I don't know how different the RISC PC might be to the A5000, but corrosion similar to that killed the equivalent in my machine. I'd go gently as you suggested since I know on my A5000, even gentle cleaning cause bits to fall off!!

[alexh]

I'd go gently as you suggested since I know on my A5000, even gentle cleaning cause bits to fall off!!

Yes the slightest touch with the soft cotton wool on my A5000 alpha was enough to knock off some "bird seed" SMT capacitors/resistors taking their pads with them.

[rubber_jonnie]

I'd go gently as you suggested since I know on my A5000, even gentle cleaning cause bits to fall off!!

Yes the slightest touch with the soft cotton wool on my A5000 alpha was enough to knock off some "bird seed" SMT capacitors/resistors taking their pads with them.

I hear ya.

[stephen_usher]

I'd go gently as you suggested since I know on my A5000, even gentle cleaning cause bits to fall off!!

Yes the slightest touch with the soft cotton wool on my A5000 alpha was enough to knock off some "bird seed" SMT capacitors/resistors taking their pads with them.

If they were that far gone then they wouldn't have connectivity anyway so they're only cosmetically on the board and would have to be replaced anyway.