Teardown of an old Soviet made PC. - Page 1
Forum section: electronics / general

author: Refrigerator
author_rank: Super Contributor
timestamp: March 21, 2014, 02:59:22 pm
content: Hello, i've found this old Made in USSR PC and thought it would be fun to tear ir apart.There was also a 260 page book with it.And there was a series of pages dedicated to programming this PC to draw the soviet symbol.Sadly, i don't have the power supply for it so i can't test this thing.After taking all the screws from the rear and opening it this is what i saw.The main board actually has four layers ! ( that's not including bodge wires )I almost instantly spotted this weird bodge (?) chip glued on top of another chip.This seems like it was pretty good at it's time, even the bodge wires on the bottom board are glued on.Right next to the weird bodge chip there is a couple of UV eraseable EEPROM and a chip which has CPU marked on it.On the other side of the main board there are a few heatsunk chips and alot on wire wound resistors.This PC was made in 1991 04 and for it's time it seems like it was a pretty nice machine for it's time.I gonna look around to find out the voltages needed to power this thing up and maybe test it.

author: lpc32
author_rank: Frequent Contributor
timestamp: March 21, 2014, 03:21:34 pm
content: I like the Soviet BASIC.Looks satirical.

author: Bored@Work
author_rank: Super Contributor
timestamp: March 21, 2014, 03:22:39 pm
content: Technically one would call this a home computer not a PC. It could be one of the many Sinclair spectrum clones produced in the USSR.The 80A-CPU is a Zilog Z80A CPU ripoff. Stolen with socialistic pride by VEBMikroelektronik KarlMarxErfurt of the former GDR.

author: free_electron
author_rank: Super Contributor
timestamp: March 21, 2014, 03:33:29 pm
content: How many arrow keys do you need ?

author: dexters_lab
author_rank: Unknown
timestamp: March 21, 2014, 03:41:59 pm
content: nice :+:is it operational?

author: Bored@Work
author_rank: Super Contributor
timestamp: March 21, 2014, 03:45:50 pm
content: It is indeed a Spectrum clone called Byte / bayt. Many made, in the city of Brest in Belarus, but these days supposed to be rare.http://zxbyte.ru/index_en.htm

author: TiN
author_rank: Super Contributor
timestamp: March 21, 2014, 05:02:16 pm
content: CoolAlso PCB seem to be 8 layer, there is marking on corner (digits 1 2 3 4 5 6 7 8 on each layer)

author: SeanB
author_rank: Super Contributor
timestamp: March 21, 2014, 05:07:29 pm
content: They cloned the ULA? or built it out of discrete logic, though with the heatsinked chips it is likely they did the logic inside a few custom chips.

author: Bored@Work
author_rank: Super Contributor
timestamp: March 21, 2014, 07:49:05 pm
content: Quote from: SeanB on March 21, 2014, 05:07:29 pmYou can try your luck with the schematics to figure out how they did ithttp://zxbyte.ru/doc/byte_scheme.zip

author: Bored@Work
author_rank: Super Contributor
timestamp: March 21, 2014, 07:58:29 pm
content: Quote from: Refrigerator on March 21, 2014, 02:59:22 pm+5 V and +12 V according to the site I referenced a few times.

author: pickle9000
author_rank: Super Contributor
timestamp: March 21, 2014, 08:03:35 pm
content: That is an awesome find, as Dave would say "A of thing beauty and a joy forever". Congratulations.

author: Vgkid
author_rank: Super Contributor
timestamp: March 21, 2014, 10:11:53 pm
content: Thanks for the teardown.

author: Shock
author_rank: Super Contributor
timestamp: March 22, 2014, 12:31:57 am
content: Quote from: free_electron on March 21, 2014, 03:33:29 pmIn Russia the arrow keys move you.

author: GeoffS
author_rank: Unknown
timestamp: March 22, 2014, 01:34:50 am
content: Quote from: free_electron on March 21, 2014, 03:33:29 pmOnly a left key, moving to the right was frowned upon.

author: xtv
author_rank: Contributor
timestamp: March 22, 2014, 03:02:01 am
content: Pretty interesting piece of hardware!Shame on you not having a psu to try powering it on..That glued chip.. Soviets were already using package on package (pop) technology that time

author: calin
author_rank: Regular Contributor
timestamp: March 22, 2014, 03:24:05 am
content: Hey, i learned to program on a similar machine ... This one:http://www.old-computers.com/museum/computer.asp?c=632&st=1Yes you can poke fun @ them but these machines have created many good engineers at got lots of kids (including me) into the world of electronics and IT.So clone .. no clone .. soviet bla bla .. It was actually a good thing

author: Refrigerator
author_rank: Super Contributor
timestamp: March 22, 2014, 05:34:19 am
content: I couldn't find the pinout of the PSU connector. It doesn't seem like this thing was used, there are two arrow keys and a unmarked key that seem to have wear on them, i suspect this was only used for playing games.

author: pickle9000
author_rank: Super Contributor
timestamp: March 22, 2014, 05:47:36 am
content: Quote from: Refrigerator on March 22, 2014, 05:34:19 amTake a pic, connector back, top, bottom.

author: Refrigerator
author_rank: Super Contributor
timestamp: March 22, 2014, 08:41:11 am
content: Here's the connector.I expect two of the center pins to be GND.

author: Bored@Work
author_rank: Super Contributor
timestamp: March 22, 2014, 09:11:16 am
content: Quote from: Refrigerator on March 22, 2014, 05:34:19 amOn the site I now referenced multiple timeshttp://zxbyte.ru/byte5.htmhttp://zxbyte.ru/doc/bp_old.ziphttp://zxbyte.ru/doc/byte_scheme.zip

author: Bored@Work
author_rank: Super Contributor
timestamp: March 22, 2014, 09:40:16 am
content: Quote from: calin on March 22, 2014, 03:24:05 amMostly we are having fun looking at that old stuff. And yes, we are also poking a tiny bit of fun at it.Don't you find it ironic and funny that the self-proclaimed superior socialistic/communistic system needed to clone, copy and steal the technology of the despised western imperialistic pigs and class enemies? Instead of coming up with something on their own? Something which by their own ideological argumentation could only be vastly superior to anything from the West. I could now link that pst propaganda and behavior to current Russian political events, where they do all kinds of funny things to proof their superiority and cover up their questionable behavior. But we aren't supposed to discuss politics here, so I leave it at that.

author: Refrigerator
author_rank: Super Contributor
timestamp: March 22, 2014, 11:39:57 am
content: I've tried looking through that site but must've missed the part about connecting the power supply. ( I don't speak russian )

author: andtfoot
author_rank: Unknown
timestamp: March 22, 2014, 12:15:49 pm
content: Quote from: Refrigerator on March 22, 2014, 11:39:57 amhttp://translate.google.com/translate?sl=ru&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fzxbyte.ru%2Fbyte5.htm&act=urlTowards the end it shows using an AT or ATX PSU to power the computer with some photos.

author: Refrigerator
author_rank: Super Contributor
timestamp: March 22, 2014, 12:59:47 pm
content: Thanks for the help, now all i need is a cable to hook up to my TV.

author: amyk
author_rank: Super Contributor
timestamp: March 22, 2014, 01:24:11 pm
content: I was going to say "that looks awfully like a standard PC Molex" and "you'd better check the pinout before just plugging an AT PSU into it", but this picture shows it pretty clearly:http://zxbyte.ru/pic/byte5_09.jpg

author: abyrvalg
author_rank: Frequent Contributor
timestamp: March 22, 2014, 01:35:13 pm
content: This is the power supply pinout picturehttp://zxbyte.ru/pic/byte5_10.jpg"B" letters means "V".!!! WARNING !!! This is PSU's side plug, not the socket on board, mirror it !!!You can use just a piece of coax with stripped ends to connect it to the TV, good contact is not required, most of those HF modulators were so powerful that sometimes I was able to tune my TV to neighbour's ZX behind the wallThis particular modulator uses SECAM colour coding, some "western" TVs may show it B&W.Having discretes vs ULA was cool - like having an "open source" ULAI still have a schematic sheet of my first ZX somewhere at parents house.

author: ResR
author_rank: Regular Contributor
timestamp: March 22, 2014, 08:47:40 pm
content: I remember soviet Estonia made "Juku" was similar in internal construction, it was pain in the arse to get it working. Also those resistors are metal film type MLT 0,125W, not wire wound. I have seen a lot of things that was made in 1989 to 1991 in soviet union utilizing western parts. But it has been a long time since I have seen a specimen, so teardown needs to wait for the opportunity. Two thumbs up to OP for good teardown.(Forum changed the cyrillic letters into ? marks)

author: abyrvalg
author_rank: Frequent Contributor
timestamp: March 22, 2014, 09:23:44 pm
content: Btw, MME Z80A wasn't a layer by layer copy, but a compatible design (like Cyrix i486). It was even possible to detect it with a software trick based on slightly different implementation of LDIR instruction (Zilog repeats the opcode fetch cycle on every iteration, MME does fetch only once).

author: calin
author_rank: Regular Contributor
timestamp: March 22, 2014, 09:28:20 pm
content: Quote from: Bored@Work on March 22, 2014, 09:40:16 amI don't mind anyone poking fun ... like I said I truly did not care or even know at that time were it was made or who claimed what. Was it superior or inferior .. ?!! who knew. All I knew it was I could get my hands on something cool .. western .. eastern made .. whatever; i had a "computer" and all is that what matter at that time . What I wanted to point out is the fact that regardless from where these things came they inspired an entire generation of kids.As for the Russian spirit .. I suppose you did not ever lived close to "mother Russia" to know what that means. I-ll just live that there .. any guys from eastern Europe know exactly what I mean. If you did then you know (sorry if I missplaced you) and what is Russia doing now wold start making some sense. Also what US and EU is doing about it.. makes sense also it is called "deja vu"

author: FrankenPC
author_rank: Unknown
timestamp: March 22, 2014, 10:49:10 pm
content: Comrades! I present to you the Kommodore?

author: iDevice
author_rank: Regular Contributor
timestamp: March 25, 2014, 07:17:27 pm
content: Quote from: Refrigerator on March 22, 2014, 08:41:11 amWhat's funny, is that it looks like an oversized Sinclair QL power supply connector...Maybe another "inspiration".