It takes a special eye to see a junkyard car and envision it as your latest hotrod. The guys at RMC found what they termed a “disgusting” Acorn Electron and decided to restore it to its former glory. The Electron was a budget version of the BBC micro with a 6502 running at 2 MHz when executing code from ROM and 1 MHz when it hit the RAM. Apparently, at least some of the bus was operating at 4 bits instead of 8. Go figure.
The 1982 machine was meant to head off the Sinclair ZX and was set to sell for about £200. However, the machine didn’t catch on like the Sinclair and undersold it by around 20 times with a paltry quarter of a million units.
Powering the machine up showed white raster on a monitor, so it wasn’t running but it wasn’t dead either. The computer had a type of programmable logic chip known as a ULA that replaced lots of interface logic and the guys knew that many common problems wind up being a dirty socket for that chip. When you see the package it is in, you won’t be surprised.
After a good scrub of both the socket and the IC, they were rewarded with a Basic prompt. So electrically, the restoration wasn’t too much of a challenge. Cosmetically, though, there was a lot of work to do and that affords us some great shots of the computer’s internals.
They did replace a few components as long as they had it open. The case stayed a bit yellowed, but at least it was cleaner and by the end of the 20-something minute long video, you can see the computer going through its paces quite well.
If you have one of these machines, it probably doesn’t have WiFi. But it could. You can even get a fully modernized version of its competitor, the Sinclair ZX.
42 thoughts on “A “Disgusting” 1980s Computer Restored”
if you haven’t done a mouse piss rebuild your a bit lacking or live in a nice area
Mouse piss is…
A) incredibly corrosive to copper, even as a vapor .. and ..
B) in large quantities the most incredibly, amazingly, revolting smell imaginable, way off the
normal “something marked it’s territory here” scale
As a young man I had to service arcade games in one place that was… not know for it’s
housekeeping. Arcade game cabinets are warm and sheltered and near ample food.
Mouse piss is a truly a terrible substance, and we should be grateful that mice are the
size they are and no bigger.
“be grateful that mice are the size they are and no bigger.”
I don’t know about that, it would be pretty hard for a capybara to get into a piece of electronics.
Would be kinda epic though…..
Yeah, I admit, I’d go to a capybara infested arcade.
On the upside everything is likely TTL and easy to solder, on the down – some chips may only exist in the bottom of some of our chip drawers….
Is this Acorn the same company that was the genesis of ARM?
How cool. Amazing how far we’ve come…I’m typing this from an ARM desktop :)
I’d suggest that the Acorn Electron was eschewed in preference to the BBC Micro. The ZX Spectrum was a lot cheaper, but it was a different market segment.
Well, the BBC Micro was also manufactured by Acorn… But that was backed by the BBC, and was part of a course program on TV.
So I would rather say that Acorn sacrificed the Atom and poured all their money and resources into the BBC. And that was a good decision, because it gave them the necessary respect to get the funding for their first ARM processor (and develop the ARM computer).
Then they almost got killed by Commodore and Atari. And made their decision to stop making computers and license their ARM architecture.
And when Microsoft got the idea of making the Pocket PC and the most popular Pocket PC’s were based on the SA-1110 (StrongARM cpu, made by DEC), ARM got it made. Since then they skyrocketed, and you’ll find ARM everywhere.
But well. When the ARM computers came in the market, I wanted one so badly. But never got one. Now I have ARM in everything (writing on an iPhone 11). But never got that feeling of the home comouter times back. :)
Ok, maybe I got it back a little with the Raspberry PIs. ;)
Not quite right. ARM was spun out of Acorn (as a JV with Apple) while Acorn were still making computers (1990 iirc – Acorn had just launched the A5000). ARM grew, and an investment bank realised Acorn’s shareholding in ARM was worth more than Acorn’s market value. So they bought the majority of Acorn shares, and asset-stripped Acorn for its ARM shares, making a hefty profit in the process.
The ‘leftovers’ (ie the company itself) were broken up into ART (basically the s/w and hardware guys, who did ARM consultancy for a few interesting projects) and Xemplar (sales – another JV with Apple to sell Acorn/Apple kit into schools). ART did an ill-advised last hurrah of a desktop machine in ‘Phoebe’ (never got a real name), and then Pace Micro bought that team, at which point the computer story was over for ‘Acorn’ (another company – I forget who – continued making RiscOS desktop machines for a while).
The SA-1110 went into the Acorn RiscPC, but I don’t think any PocketPCs were based directly on the SA1110 – the Dell Axim X5 had a successor (by then owned by Intel) SA chip – the PXA270 ‘Bulverde’ though.
Ah, not sure on the Acorn but after refreshing my memory the SA-1110 went into some popular handhelds, the Sharp series among them (I own one and saw the designation frequently).
The SA-1100 from the DEC/Intel transition era wasn’t as much of a success. Unless it made it into non Psion devices not noted by Wikipedia.
Now that I didn’t know. A quick google enlightens me! And also reminds me that it was the SA-110 in the RiscPC, not the SA-1100 onwards. I’d also completely forgotten about the SA-1500. Fun times…
Yeah, ARM was out there, but in the early Windows CE days the shareware archives tended to be divided into MIPS R4000 and SH3 sections.
Electron .. according to the BBC docu drama “Micro men” (available on Youtube), the reason of Acorn downfall… and ARM rise!
The RAM is shared between cpu and video. So that is the reason for slowing down. C64 has the same issue.
It’s a bit more complex than the C64, which just splits RAM bandwidth 50/50 between the CPU and VIC-II. The 6510 can’t run faster than 1MHz, even if the display is disabled.
In the Electron the ULA chip acts as a memory controller, with the system RAM attached to it via a 4-bit bus and the CPU via an 8-bit bus. The RAM runs at 4MHz, so gives the same bandwidth as 2MHz 8-bit RAM. That’s obviously not enough to feed a 2MHz 6502 and also the video system, so the CPU only runs at 2MHz when accessing ROM as that doesn’t need to be shared with the video system.
When accessing system RAM the 6502 is throttled to 1MHz in screen modes 4-6, which have a small memory footprint. In the more demanding modes 0-3 the ULA actually stops the CPU clock during screen refresh, reducing effective speed to around 0.5MHz.
But there’s a couple of interesting wrinkles in this scheme. First, any RAM attached to the expansion connector (‘sideways’ RAM) doesn’t have to be shared for video access and thus runs at the full 2MHz. The ElkSD128 featured in the RMC video (full disclosure; I designed it) adds 128K of RAM to the Elk, all of it working at 2MHz. Any code in that memory runs as fast as it would on a BBC Micro.
There are also ‘turbo boards’ that fit between the CPU and motherboard, these allow the section of main RAM not used to store the screen (up to 12K) to be accelerated to 2MHz. This pulls up the Electron’s performance close to the BBC Micro (not 100% as screen writes are still slower). These were popular with Elk owners back in the 80s, and I recently did a modern open-source version; https://github.com/ramtop-retro/ostc
There are hundreds of retro-restoring videos on YouTube, but people only ever link to the main guys, like RMC and 8-bit guy.
Please, if you like retro computer content, hunt out the channels of the people with smaller subscription numbers and watch & sub to them instead.
Do you have a list of a couple you’d like to mention?
Retro Recipes – https://www.youtube.com/c/Perifractic/videos
Adrian’s Digital Basement – https://www.youtube.com/user/craig1black
Jan Beta – https://www.youtube.com/channel/UCftUpOO4h9EgH0eDOZtjzcA
8-bit Show And Tell – https://www.youtube.com/channel/UC3gRBswFkuteshdwMZAQafQ
GadgetUK 164 – https://www.youtube.com/user/GadgetUK164
Noel’s Retro Lab – https://www.youtube.com/channel/UC2-SP1bYi3ueKlVU7I75wFw
Mark Fixes Stuff – https://www.youtube.com/user/markfixesstuff
flashjazzcat – https://www.youtube.com/c/flashjazzcat/videos
Hey Birt! – https://www.youtube.com/channel/UC2V0T-vGOewtuCW3pazzczQ
8-bit and more – https://www.youtube.com/channel/UCmyydM9_kZHk49GXC4r-FKw
This list is courtesy of Thomas Kalbe, who just posted it on Facebook yesterday in the C64/C128 group, complaining how 8-Bit Guy seems to get all the subscriptions to his channel, while the other are just as great but seem to be left behind.
They’re all great channels, worth watching. :)
Love how you’ve linked to Mark Fixes Stuff when he’s in the video XD
Mark from Mark Fixes Stuff is the guy doing all of the actual repairs. He occasionally collaborates with RMC. Thanks for the list, I already subscribe to most of these. I’ll add 8-bit and More plus flashjazzcat to my list of subscriptions. The 8 Bit Guy really hasn’t been releasing videos that often lately due to Covid, the Texas Ice Storm that flooded his house and his focus on shipping his latest game. Sorry your Anti-RMC, I enjoy his channel along with lots of other YouTubers that focus on 80s early 90s retro computer content.
Those are the “main guys” Anti-RMC was talking about ;-)
there are loads out there, not to mention me.
Retro Tech Ralph – https://www.youtube.com/c/retrotechralph
YouTube doesn’t limit the amount of subscriptions you can have, so why not subscribe to the larger *and* the smaller channels?
It’s a great list you’ve posted, the more retro the better.
Seriously? They call this “disgusting”? :P I have cleaned computers with so much dust and dirt that I decided to wear a face mask, just in case. :)
But good job anyway!
They meant Electron internal architecture, the way it handles ram is disgusting.
We restored a computer that was covered in chicken shit. It’s one of our restoration, “Museo dell’Informatica Funzionante”. Also, we had a SUN SPARCStation 5 with a rat nest inside it. If this is “disgusting”, what are thooooooose #LOL
I was going to say disgusting is when you have to evict former tenants :).
I need internet, open source etc.
Why not creating macintosh II SE clasic put faster memory, ethernet, wifi, open source rom (like wine)
I need zx spectrum but with normal keyboard and mobile (offgrid)
So, basically a normal modern PC?
Speaking of disgusting, I once had to work on a PC from a snack bar, and yep it was full of caked grease. Utterly disgusting and amazing it still worked.
That’s not disgusting. This is:
Commodore 64 left outside for over a decade! Could it still work??
“These things are robust you just plug them in and they either work or…”
‘K. Now I want to know what they used for capacitors!!!
I’ve got one in the loft. Bought off of a schoolfriend so I could play Dare Devil Dennis. Happy days.
It’s an honour to be featured so a big thanks to Hackaday.
Also big thanks to those who think I shouldn’t be feature and simultaneously should be featured. Like Schrödinger’s YouTuber…
Mike’s old computer is about 100x as interesting as that advertisement loaded rubbish with silly background music.
Not sure why you have to share another persons video whilst making salty comments mate. Jealous tears are not a lubricant for success. It’s a shame because now you’ve cast that content producer in a negative light. If you don’t like things it’s easy not to watch them, and moaning about something you neither pay for or like makes you sound entitled to be honest.
Oh no! They’ve ruined one of the rare original “green label” prototypes!
That could have been worth a fortune….
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