Keeping yesterday's computers ticking takes more than nostalgia ARCHAEOLOGIC Repairing and restoring vintage computer hardware has grown increasingly popular, but keeping decades-old machines alive presents different challenges from fixing modern kit. Earie Salmon, of the YouTube channel Earie's 8-Bit Workshop, is one of many tinkerers documenting the process of keeping retro computers …
Articles like this, please, much preferable to reading about some incremental increase in resolution of yet another boring phone.
I really admire people who can do this and I even understand a lot of the electronics, but unfortunately I am that person who solders with a spoon.
For anyone interested in this stuff, I heartily recommend Usagi Electric on YouTube, the chap is a genius and a great presenter. Recommended.
https://m.youtube.com/@UsagiElectric
where you concentrate on placing a probe and your hand accidentally touched a high‑side power component
Been there, still here. I was about 13 or 14 at the time, and it was when probing a transformer.
Got thrown/I just stayed on the floor recovering. A bit like one of those looney tunes cartoon characters after getting knocked on the head and getting dizzy/swirling stars effect
Not just mains. Charged electrolytic capacitors, especially big ones can still give you a belt, even after mains is removed. If there is sharp metal around, the involuntary reaction tends to cause you to gash your hand as well.
And HT from a tube TV or monitor can be even worse.
Still bear the scars of both of these when learning this from 50 years ago. HT burns don't heal well. Faint, but still there.
Bit of a shock but unless you have your bare feet standing in water it isn't going to cause any real problems or least it hasn't on the many occasions I've been shocked.
But I've always been careful around capacitors, especially larger ones. If we still had those old style TVs I would 100% call someone to repair it rather than poking around to see if I could figure out the problem on my own! Some of those were lethal.
You bet that is by design
It is very common to have a heat sink at a high potential.
typically if a part is dissipating enough heat to require a heat sink the component in question will have all or part of its casing in metal.
Adding an insulator impedes heat transfer (even if there is one fitted over time they degrade) so always assume a heat sink is live
I have mentioned this before but using a bare screwdriver as a Scope probe and touching a (live) triac heatsink had blobs wizzing down the tracks and 74LS chips blowing their tops off.
Repaired and working afterwards .
Do a lot of 8 bit micro-controller tinkering these days and all my boards are hand built using veroboard, good old 0.1" through hole soldering - can't get on with microscopic surface mount stuff that the surviving electronics magazines seem to have switched to these days, although I do understand that a lot of modern electronic components are *only* available in surface mount.
I fear the traditional electronics enthusiast are a dying breed unlike the 1970's when I got started.
Anyone who is interested in this activity might enjoy a YouTube channel, "Noel's Retro Lab", here:-
https://www.youtube.com/@NoelsRetroLab/videos
He covers repairs to all sorts of different makes and models of computer - Atari, Sinclair, Dragon, Commodore, on and on.
I found my way to his channel after a search for a "starter electronics kit" turned up this specific video:-
https://www.youtube.com/watch?v=dR8nqJzrnSg
To be fair, there are dozens of channels and thousands of videos on YouTube that cover this - I'm sure there are many others people could recommend. But this is an excellent place to start.
A comment worthy of the BOFH…
but much, much kinder:
"I don't want to talk anyone down," … "but… their confidence exceeded their skills."
Indeed no mention of the ancient and most excellent Order of the Striped Apron.
Back in the day, when our product was sold in Boots, I received a support call about the length of the connector*, could he de-solder it & pull it forward a fraction for extra clearance\pull it back for a tighter fit as he had a soldering iron....
I vaguely recall advising him it would void his warranty but stupidly trusted in his abilities it was the 80's & all sorts of tinkering went on.
Some months later... a shipment of repair under warranty devices came in from Boots, I opened up this one box & that phone call came flooding back to me, the 8PTDT switch was in pieces, heat gouges & the traces destroyed, because this guy's soldering iron was a plumbers soldering iron.
I sent it back saying this wasn't warrantable repair with a lengthy letter of my findings, a few weeks later the branch rang me up asking why it wasn't repaired, as the prototype Kieran* complaining loudly about his interface, why it wasn't repaired or replaced. It transpired that my letter had got misplaced so I took great pleasure in reading it to her (Off my Amstrad PCW8256 screen), she listened with equal pleasure & said she was greatly looking forward to informing the customer of this on his return, I think I faxed her the letter (she didn't have a email address).
*From memory this was our comms interface for the Spectrum128.
**Male version of the Karen.
The capacitors degrade over time. Hence 'recapped' appearing in adverts for refurbished gear. Large capacitors are typically part and parcel of the power circuits.
You can get memory card adaptors for several early machines. Helpful as neither cassettes nor floppy drives/microdrives were designed to live forever.
If you have an old Mac that appears dead, a new mobo battery may be all you need. Whilst PCs come on forgetting the date, Macs often play dead with one that has expired.
"always keep the mains voltage covered to prevent you accidentally touching it"
And always use an RCD which will cut the power in time to save your life! Test said RCD with the button first. If you want to be really careful, put it through an isolating transformer.
Actually, best just avoid mains.
Also, remember, if you're trying to resurrect something like a PET, Sharp MZ-80K or Amstrad 8256/9512, etc. with their built-in screens those CRTs need something in the region of 10kV (something with an integrated colour screen even more) and those capacitors in the flyback circuit will put a dangerous voltage on the CRT anode, even for some time after the machine is switched off.
A fact I learned the hard way...
CRT's are electrically capacitors & even a dead set for many years, if briefly powered on & still seemingly "dead" they have already stored a massive charge in those few seconds if you FAFO by going to remove the final anode cap on the now powered down TV.
Industrial electronics & indeed computing seemed a safer career path.
Just to be clear - for the first 5 years of my employment life I worked testing, repairing, and latterly designing circuit boards - from PSUs that had to handle a 10000V Megger isolation test, to 16 layer ejecter seat controllers. Tools I had to master - over a dozen different soldering iron tips, variable and fixed voltage irons, Pyro Pens with both naked heat and tips attached, variable heat guns, desoldering ovens, different solders, a dozen or so tweezers, forceps, pliers, and custom chip extractors. I still have much of the same equipment at home, although not in use as often as I would like - pressures of life I guess.
Anyway, I regularly pop onto a youtube channel about a computer restoration, or sometimes car restorations with "modernised computers". Many a time I see the presenter with a soldering iron that's more akin to a garden spade than a precision instrument, or using a Pyro Pen to extract a through board resistor. Sometimes it makes me nausious just watching tracks lift from excess pressure or heat, and the fix is glue, or putting solder in the through board hole, or just throwing more solder at the component. There's so much bad practise that i sometimes fear for the life* of the users of the now "fixed" circuit boards.
* Solder is not a substitute for copper or iron/steel making contact. Solder has a much higher resistance and is thus prone to generating heat on higher power curcuits (such as car relay boards). Solder in general is meant to hold the contacts in place, not be a conducting agent between them. Only in specialised cases is the solder itself meant to be part of the conductive path.
Show a kid today a wire-wrap gun and they will laugh at you
- actually they will barely glance up from their phone, while making vague grunting noises.
I swear my German Shepard is brighter than some of these people. My Border Collie definitely was, but I always suspected she was brighter than me and just humouring me.
I was toying with getting some of my old favorites back, but this stuff is quickly starting to become silly expensive.
Then someone released a humongous ISO image with all the emulators and software and I decided that that is good enough for me. https://virtualosmuseum.org/
Great fun and no electrocution risk!
(Always one hand behind your back, kids, when probing live AC!)
"(Always one hand behind your back, kids, when probing live AC!)”
And also, if possible stand on one leg! The logic being that if you do touch a live contact, the current will ground itself down one leg (assuming that you are standing on the right single leg), rather than passing across your chest and doing unfortunate things to your heart rhythm. Now although I do get the idea, I’m not too convinced that this is helpful in any way.
I have had precisely two belts from mains electrical supply (UK so 230-250V), neither of which were pleasant. In both cases the jolt caused muscles to contact and pulled my hand away, as opposed to gripping the live terminal and not being able to let go - in which case you will not be having a good day. However the first time was many, many decades ago, where I was installing an early touch-sensitive light switch, This involved turning a variable resister with the power on to calibrate it. Although I was using an insulated screwdriver, it was obviously not insulated enough, or somehow I was touching the metal part. When my hand whipped back, I managed, somehow, to stab myself in the face with said screwdriver!
It's becoming an increasing issue for many older systems. I have a couple of old Silicon Graphics systems and the power supplies for these things are becoming increasingly troublesome. One "reseller" I've spoken to has boxes full of dead Indigo2 IMPACT power supplies and has pretty much stopped selling his remaining working ones because they've become so failure-prone.
The problem is that it doesn't just seem to be a case of re-capping them, there's other parts that are failing as well - and when they do go pop, other components can be damaged in the process. Repairing is a major issue: They're custom PSUs, SGI hardware is quite niche and there's pretty much no documentation at all for them. Hence trying to truly figure out how they work and how to properly repair and overhaul them is incredibly complex - not to mention the fact that each generation of system came with a completely different PSU - and this is just the power supplies. Other components on these systems are also showing their age and begging to fail more often.
It's way beyond my capability and skillset, but I have the utmost respect for those that manage to reverse-engineer and repair old systems like these so they can continue to be enjoyed for generations to come.
I'm afraid most SGI machines are very particular with power and often require large current draws on voltage lines such as 5v that have much lower outputs on most modern power supplies. Plus, many of the pin-outs are also not documented either. It's not a complete non-starter, but these things are remarkably finnicky with power. A working "lab" setup wouldn't be cheap or easy.
I do know that some hobbyists have managed to retrofit an ATX power supply to the Fuel by using a custom adapter board, but the Fuel is the most PC-like and doesn't use less common voltages and/or current draws.
It's certainly the case that for various Sun systems the network address is stored in a module with an embedded battery which expires. It's possible to either get a new module and re program it, or take the existing module and scrape/burn the package until the contacts are visible, then solder a CR2032 holder on to it.
I've done this with a Sparcstation 20 and revived its connectivity.
Apart from the safety warning about working with mains electricity...
Don't plug in a vintage computer that's been in storage and turn it on to see what happens.
There's an infamous brand and type of mains voltage-rated capacitor used in a lot of computer power supplies that degrades over time and is apt to depart this world with a bang and a cloud of smoke.
Those in the know 'check for Rifas' before powering up and replace them first.
Hence Rifa (Company name) = Replace If Found, Always
I spent many an hour in my early to late teens tinkering with Spectrums, BBCs, Electrons etc etc. Got to be quite a dab hand with a soldering iron. I miss those days. I still remember the sight (and smell) of a Spectrum ULA that had burnt a hole though itself and the board underneath when the kid that owned it plugged a PSU (not the original) into the MIC jack at the rear. Apparently there was a LOT of blue smoke....
Managed to get it working again too, but it looked like a cat's cradle.
Excellent! Another channel to add to my list of places to get my fixing fix, and a couple more in the comments too - thanks guys!
It's always good to see vintage kit restored to working order. Perhaps, one day, I'll have go myself, if time and eyesight permit, but for now I'm happy to watch.
got my Spectrum sitting next to me.... dunno if it works, it sacrificed its PSU for some long dead project, my memotech mtx still works... if only I have a decent TV to plug it into and I dare not try the Atari ST why? because the first thing I'll do if it works is load in dungeon master and thats me gone for another weekend ........
After a break of many years I've got back into soldering, courtesy of Small Computer Central and RC2014. Whilst this is still computer based, there's something compelling with working on hardware rather than Yet Another Software Problem. I'm enjoying this to the point that the next stage is a (fairly simple) circuit from scratch.
SCC kit tends to be 80 pin, RC2014 is mostly 40.
This is almost all through hole, and tolerant to a moderate extent of inept dabblers. I've just built one of the SCC CP/M kits, a Z180 with 512KB, and a switchable ROM monitor or BIOS running CP/M or BASIC. On to that I've added a compact flash card, a VGA/keyboard interface, and am adding a backplane extender[1] and some digital and analogue I/O.
That provides a solid state, low power system capable of booting into various CP/M type systems and other associated Z80 based OSes.
If you go RC2014 the world is your oyster. It's basically cards on top of a backplane. There's a number of Z80 options, but also 6502 etc. Then you can add video of your choice - simply a serial output, a VGA text out, or i.e. a TMS9918A board switchable to the port locations of various old 8 bit micro locations. So, it's possible to e.g. construct an MSX from a series of plug in ports.
It's probably not the best option if you're explicitly looking to build a specific 8 bit micro (there are other replica systems which handle that better, and the stability of the 80 pin and in particular the 40 pin connectors are sometimes worse than old edge connectors of yore, although probably not the ZX81..)
[1] I would recommend one of these from the start if you're using a kit with only a couple of sockets, two is not really enough. Also, if you use the SC715/SC729 it may need a 5V connector, and it'll be easier to use a backplane with a 5V connector than find one on the main board. Ask me how I know..
