Restoring a Soviet-era analog synthesizer | Hacker News Reader

Restoring a Soviet-era analog synthesizer

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206 pointspmoriarty44 comments

Yeah, that's where Open Source was born - in USSR.

I do remember that each consumer device was sold there with its schematics, assembly/disassembly and installation instructions. And that was the law.

> "I do remember that each consumer device was sold there with its schematics, assembly/disassembly and installation instructions. And that was the law."

That's interesting. I wonder if there's a archive of those schematics/documents for Soviet consumer devices somewhere.

I guess you can just do image search for [принципиальная электрическая схема].

A lot of western instrumentation and test equipment used to come with full circuit diagrams and assembly info. The understanding was that your HP spectrum analyser or Tektronix scope cost so much money that if it broke then you would have it repaired, and to do the repair you need the circuit diagram.

Not any more, of course. It also deserves to be mentioned that lots of higher-end equipment used a lot of custom parts, and not always out of necessity (like custom µPs in HP multimeters, or stuffing solenoid drivers into unrelated hybrids ... and of course anything handling higher frequencies almost always used some custom chips or selected transistors hidden behind opaque part numbers).

Sometimes there are still schematics, Agisight still does it e.g. for low-end power supplies.

Yes, similar information used to be made available for Western electronics. In addition to engineering equipment, consumer electronics such as TVs and radios, and even computers had full schematics at one point.

As an example, can see hardware schematics in the Apple II Reference Manual found here:

http://www.applelogic.org/UserManuals.html

I'm mostly interested in the Soviet material as I'm assuming that because it was a legal requirement the types of documented designs will be more broad, but if you know of an archive of old Western schematics also, I would be interested in taking a look.

At least for home computers, much of the schematics and manuals have been preserved through the dark ages of the 90's by home computer enthusiasts and put on the internet thankfully.

For instance (not Soviet, but East German): here are a few links to manuals and schematics for the East German KC85 computers:

http://floooh.github.io/virtualkc/p060_links.html

But this sort of detailed schematics 'coming in the box' was also common for Western home computers, and it's all preserved. The same for reference manuals of CPUs, and especially support chips. Without these, writing emulators would be much, much harder.

There are websites created by enthusiasts of different categories of equipment: audio amplifiers, radio receivers, home computers, synthesizers. Easy to google "device_name схема".

I think it was the norm at the time. Even toy Amstrad computers in the 80s came with Basic manuals. Manufacturers expected a lot more from the consumers, I guess because tech at that time was more a beautiful new thing rather than a product to sell regularly.

The Apple II also had schematics, and a listing of the Monitor ROM. Quite a contrast from the sealed-box-no-serviceable-parts-inside philosophy that they went to starting with the Mac.

I wonder if Lenovo keeps the service manual tradition alive for thinkpads.

You know it's all consumer dynamics. People buy even without, then why bother.

Yes, they do. Just google "thinkpad nnnnn hmm" for the Hardware Maintenance Manual, or "thinkpad nnnnn psref" for the "tbook-style" datasheet, where nnnnn is the model number.

I got a service manual for an old camera and it is a fine, complete piece of technical writing, literally all the information one would need to fix any problem with the camera.

It dawned on me that in the 70s things needed to be that comprehensive because ... no internet!

In college a teacher told us that before internet they had to wait a month just to have a reply with a catalog of papers from another university; then more months to get a print of their selection. Now they have the whole series in an hour. But for the consumer market this went the opposite way.

> Even toy Amstrad computers in the 80s came with Basic manuals

You're likely talking about the Amstrad CPC, I'm not sure why "toy" should apply to it : it was the best selling 8-bit in several European countries, and by far the most capable of all (the C64 had better sound but much worse graphics, and the ZX Spectrum well... let's be charitable and say that it had at least price going for it.)

For some reason, the Amstrad was underrated in parts of northern Europe (and especially the UK, its homeland), usually in favour of the C64 (fair), and the ZX Spectrum (IMO inexplicable)

Compare screenshots of Operation Wolf, Gryzor, Barbarian side by side on CPC/C64/ZX and you'll see what I mean.

it was marketed as a game machine for children, hence the toy, sure it's a full fledged computer but it wasn't really sold as a programmable device, yet it came with a basic manual

Wasn't every 8-bit home computer marketed as such though?

While selling devices with schematics was a common practice everywhere, you are, interestingly, correct. The USSR had the government organization, GosFAP(ГосФАП, National Fund of Algorithms and Programs), which was enforcing sharing of code in the country. I recall reading in some memoirs that it effectively shunted software development as you had to register any software with it and it involved printing source code, filling forms and traveling to the physical location of the office and interacting with a number of officials for a number of days. And even if something got registered there it was for the version 1.0 and never had been updated.

I'd call this a servicing more than a restoration. The thing looks incredibly well built with an eye towards serviceability over ease of assembly - pretty much exactly what I would expect for a Soviet built appliance.

There was plenty of awful Soviet tech, too - this thing has survived because it had some value, was well built and taken care of but you don't hear about the thousands of pieces of tech that were shoddily made cheap crap (though expensive for a Soviet citizen) and wouldn't last a year without repairs.

Soviet tech had to be built for serviceability - people couldn't often afford new things and even if they had the money, there was no guarantee it was even available. And many things just broke down constantly. It even went so far that "a set of golden hands," meaning one could fix a lot of stuff was a valued characteristic in males, and women sometimes may have overlooked other personality flaws in a relationship because of it, like drinking.

My grandma had a Soviet TV well into the 90s and even early 2000s, maybe out of sentimental attachment more than anything else. The thing broke down constantly, every 3-4 months at least, and she'd always call a repairman. In the end I think more money was sunk into it than a brand new 4K TV would cost now. It was finally laid to rest when her usual TV repairman died, and the new one found it increasingly difficult to find replacement parts, and finally gave up, and we could at last get her a new TV.

>Soviet tech had to be built for serviceability

also there were significant sharing of tech between military industry and consumer (one can say that in many areas the consumer one was just a minor branch off the main military industry, kind of a USSR version of COTS). TVs and control boards of cruise missiles used the same electronic parts and were built using the same skills/processes - the consumer parts (like transistors, etc) were just the ones that didn't make the higher quality military bin (the military binned parts were marked "VPK" - "Voennaya Priemnaya Komissiya"/"military quality check", and these ones you'd prefer to use in your own electronic projects when/if you could get them).

Just a datapoint: lots of czech(oslovak) devices contained large amounts of MH54xx military grade TTL logic, because it was more readily available than lower-spec MH74xx (and I believe that both soviet-made KL555xx-series and east german D1xx-series of SN74xx TTL logic clones didn't have different reliability grades)

To make a counterexample, my grandmother had a Zil refrigerator she bought in the 1950's (http://i.imgur.com/POw7U6R.jpg) that worked for over 50 years until the late 2000's. It would have probably worked another 50, if we hadn't changed it for a modern larger and more energy efficient one.

Well, yeah - I think most of the stuff was overbuilt by modern standards so it should work for a long time, just that often the build quality would be shoddy, or had improvized components. I didn't mean that one TV example to be the definite example, that was just an anecdote to illustrate the general point.

It's not only Soviet built things would last longer. US washing machines, refrigerators made in 50-60s also last forever. The ones you buy now, the way the are made and painted will rust in couple of years and will be thrown to garbage in 5 years. And no, it's not because it's cheap to buy a new one, they are just simply bad.

You can actually buy decently made appliances nowadays, it's just that the majority of people don't want to spend that much money. A $300 washing machine in the 50s was much better than a current washing machine at the same price but that amount of money in the fifties is $3000 now. A $3000 modern washing machine would probably blow the 50s one out of the water.

Unless you buy insane super-appliances, long-lasting appliances typically cost 2-3 times the consumer average.

I bought a Miele washing machine in 1996, and it's still being used today. It was about twice the price of machines that I'd had to before that never seemed to last more than a few years.

It's cheap to buy a new one for the features. It'd definitely be cheaper to buy a washer with 2010s construction and 1950s feature set, but that's not what consumers (or environmental regulators) want. Likewise, a modern washer with 1950s construction would be outrageously expensive, not to mention material and energy inefficient. (Keep in mind that the operating cost of an appliance is a significant fraction of its total cost)

I'd also like to see a good data set of real prices of appliances over time.

Edit: Here's some examples of 1950s appliances: http://www.thepeoplehistory.com/50selectrical.html

Washer + Dryer in 1953: $494.90

Average monthly wage in 1953: $ 3,139.44 [0]

Average monthly wage in 2013: $44,888.16

So a 1953 washer+dryer cost the same amount of labor as a $7076 washer+dryer today.

[0]: https://en.wikipedia.org/wiki/Average_Indexed_Monthly_Earnin...

I'm pretty sure those "average monthly wage"s are not exactly per-person. The average person in US certainly did not make >$500k/year in 2013.

I think he meant average yearly wage.

Yep, that's correct. Doesn't change the math though.

Still running strong. Mine is from 1940s.

It a faithful copy of a decent General Electric fridge, so no wonder.

I think that building for serviceability would be better than the planned obsolescence with the latest fad included (washing machines with touchscreens). That doesn't necessarily mean poor quality, even if it sometimes did in the Soviet Union.

Being well built says nothing to how durable the parts are that were used to build it - the parts might have been awful - but it was clearly designed to be easy to repair.

Reminds me I have a PSR-420 to "service"

That's a great piece of work - it's wonderful to know that old electronics are being cared for.

If you're curious to see one in action - https://www.youtube.com/watch?v=zlP5hdPVB18

so rad

Another one : https://youtu.be/6SRYIPlt3z0

The upside-down mounted capacitors seem weird. They are particularly visible in the modulator board picture[1], but are also on other boards. Anyone know why that was done, or seen such assembly before?

[1] http://i.imgur.com/VNEpWkS.jpg

Stress relief. Thermal / moisture expansion of the PC board (and this looks like shoddy phenolic paper) bends the leads a tiny bit and the bending forces go through the component. By making the leads longer, they are less stiff and require less force to accommodate, so less drift due to this.

It was a relatively common method in precision electronics.

There could be other reasons as well, e.g. if these were ceramic capacitors they might do that to avoid cracking issues. (Because ceramic capacitors drift a lot by themselves, a drift/precision explanation does not make sense)

I've taken a good amount of Soviet-era electronics apart and those capacitors (the red ones) crack very easily. I think they are ceramic.

In fact I remember being deliberately careful around them as they were easy to bend, when reaching in a tighter space to solder or adjust some variable resistors or capacitors.

I would add that there exists another standard method for stress relief http://we.easyelectronics.ru/Tools/formovka-opornogo-ziga.ht... (link in russian).

Here's the Alisa 1387 album it mentions at the beginning: https://www.youtube.com/watch?v=3K9g0Kmznxc

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