Several months ago, there I was, minding my own business, when the phone rings and it’s none other than our own Dave M (Arcadian). We do chat from time to time but this time, there was a particularly excited thrust to the call as he’d just purchased a large quantity of empty/unused PCBs that previously belonged to Slogger Computers – one of the most well known producers of Electron upgrades in the 1980s.
It turned out that amongst Dave’s amazing find, and the word ‘find’ does not begin to do justice to Dave’s efforts to enable that ‘find’, there was a good stock of what transpired to be a revised and updated version of the Pegasus 400 Disc Interface PCB for the Acorn Electron. This standard of P400 PCB had not to our knowledge ever actually made it to full production as a deliverable unit and whilst I already had a P400, as did Dave, we did not have access to any schematics or drawings of any standard of board and so the challenge was to somehow figure out how to turn ‘Pegasus II – The New Batch’ into a functional unit
I will now necessarily skip a thousand details and show you this – a fully working prototype of what Dave and I now refer to as the Pegasus ‘Phoenix’…
- p400 prototype (s).jpg (29.32 KiB) Viewed 9791 times
“Brilliant, that’s really nice for you both” I hear you say. Well, you know us and of course we didn’t stop there
So Elk lovers, feast your eyes on the following …..
- six production p400's (s).jpg (34.87 KiB) Viewed 9793 times
- p400 pp001 front (s).jpg (28.95 KiB) Viewed 9803 times
- p400 pp001 back (s).jpg (24.74 KiB) Viewed 9791 times
- fitted & working.jpg (33.74 KiB) Viewed 9738 times
In case this is all new to you, the Slogger Pegasus 400 is a disc interface for the Electron and it simply plugs into a Plus 1 expansion unit (as shown in the photo) or into a third party equivalent such as the Slogger Rombox+. The Pegasus is completely self-contained and once fitted to your Elk you can plug in any BBC Micro-style disc drives, 5.25” or 3.5”, via their 34-way ribbon cable and off you go. (Note that the Elk doesn’t have an auxiliary PSU connector for drives so any units you use will need to have their own power supply). If you don’t already have a BBC disc drive, then probably the simplest DIY way to add a drive is to salvage a 3.5” unit from an old desktop PC together with the PC PSU to power it. Alternatively, BBC Micro disc drives can usually be picked up cheaply on eBay.
There were several disc interfaces marketed for the Electron but this definitely ranked amongst the best. Just some of its excellent features are…
• Very comprehensive DFS command set including format and many useful disc management commands unique to the Pegasus – have a read of the attached manual, itself an impressive document compared to other manufacturer’s efforts!
• Fully compatible with the BBC Micro DFS
• Acorn ADFS can be fitted in place of (or together with) the Slogger DFS if required
• The board has it’s own SRAM chip to use as a disc buffer area and hence PAGE remains at &E00 to allow maximum compatibility with software that has been transferred from tape to disc
• There is one spare ROM socket which can be used to host additional versions of DFS or ADFS or any Elk utility roms such as Starmon etc.
One of the really attractive features of this specific board build is that I’ve chosen to socket every single IC with the huge benefit that if you were ever unlucky enough to suffer a fault, even the non-technical can fix one by simple IC substitution. This means that you will have a disc interface for your Elk that will last a lifetime and beyond. Trust me, if you have an existing interface with soldered IC’s and no circuit diagrams, fixing a fault can be an absolute nightmare, even for techies. Of course, the likelihood of a fault occurring on a new Phoenix is absolutely minimal since all the IC’s are “new old stock” having only been powered for an hour or so during burn-in test of the boards. We have even gone the extra mile and fitted brand new VSLI 1772 chips which, as I’m sure you are aware, are the higher spec relative of the original 1770 and allow the connected drives to perform at their best.
There is just one down-side to the Phoenix tale in that sadly, we were unable to find any original cases for the boards. However, this is really only a cosmetic issue and back in the day, many owners would operate interfaces such as the Pegasus 400 and AP3/4 with the plating removed since this would give immediate access to the panel of ROM sockets thus enabling Eproms to be switched more easily. Furthermore, other manufacturers (such as Solidisk) also intentionally shipped Electron Disc Interfaces without any casing.
If you are really keen on having the board cased, I have done some cursory research and it shouldn’t be too difficult for anyone to find and modify a suitable plastic case or even to fabricate a simple flat plastic front and back plate. Indeed, we can happily supply photos and dimensions of the original case and it would be a nice little project for a local engineering apprentice or even for a High School engineering student – GCSE and A-Level tutors just love this sort of thing when covering ABS moulding techniques.
Ok, I know you’ve skimmed straight to here because what you want to know most of all is “How much…?”
Well, we have decided to give first refusal on the boards to members of the community at £40 each, inclusive of P&P, which is a good deal less than we’ll be seeking should we end up having to take the eBay route.
This might still sound like a fair bit of cash, but if you’ve ever seen Elk disc interfaces being sold on eBay (and that won’t be often!) then you’ll know they always command a princely sum especially bearing in mind these would have been second-hand units, not brand-spanking new ones like ours!
In fact, I’ve been reliably informed that only 4 x Pegasus interfaces have been sold on eBay in the last 10 years (one of which was bought by yours truly) and on each occasion, over £100 ended up exchanging hands. So the bottom line is that Dave and I are not doing this for the money – you can trust me on this.
We can also offer additional ‘power-ups’ such as an Acorn or Pres ADFS rom (to give compatibility with software that was released for the original Plus 3) and/or the excellent Tape2Pegasus400 rom which virtually automates the process of transferring software from tape to disc. We haven’t particularly thought about prices for any extras but were thinking along the lines of £5 for one Rom or £8 for both.
So … if you’d like to reserve one, please leave a message in this thread or contact me via PM.
And of course, the very first person to purchase will become the proud owner of unit/serial number SL2K-PP001 … which will surely become a collector’s item in the future!
Martin
and I've a BBC 5.25" drive kicking around as well.
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