Mystery КР580ВМ80А (Intel 8080A) Machine: Part 1 (First Look) [#TCE0691]

Added: 2026-05-20

[00:00:05][music] [music] >> Good day. Good day, comrade subscribers.

[00:00:16]Hope you're all well.

[00:00:17]A little souvenir from uh Estonia early 2000s when I used to live in Finland.

[00:00:22]Anyway.

[00:00:23]So, I don't know what this is. I'm not sure what this is. It came in this box.

[00:00:28]>> [clears throat] >> So, it's got every technical specification number. What is it? TU 25-7458 {dot} 000 something.

[00:00:39]So, I think this box is for the um Soviet Ukrainian Ukrainian Soviet Ukrainian SSR UMPC R computer, which I've um I've done a few videos on that. Still work in progress.

[00:00:56]This is not that computer. Definitely not the computer. So, it kind of fits.

[00:01:02]But, no. I do not think this computer goes with this box.

[00:01:07]So, what is this? I don't know. I'm That's what intrigued me about it.

[00:01:15]Uh it's basically got what I assume is a power cable, which is very very long.

[00:01:32]And a single five-pin DIN port.

[00:01:36]So, normally on these sort of machines you'd have that for say a magnetophone cassette. And then you'd have say an RF modulator output or another DIN for video.

[00:01:47]Um but this is all there is. So, uh I don't know.

[00:01:54]I I'll kind of suspect maybe might be an Radio 86 RK based machine kind of home home built, but it's a nice solid case.

[00:02:07]Really good solid. There's no factory marks on it, which makes me kind of think it is homemade.

[00:02:13]Um Now, the interesting thing is it's got a QWERTY. If you look at the Latin characters, they the the Cyrillic is always the same kind of but um it's a QWERTY keyboard, QWERTY layout, not a JCUKEN, which would which would match the um Cyrillic.

[00:02:32]So, Soviet computers at the time always kind of had a JCUKEN in my limited experience.

[00:02:39]Uh and it doesn't really have the the keys that you would expect. So, I think maybe maybe this is just a keyboard.

[00:02:50]Uh we've got Russian Latin or Cyrillic Latin Alt, which is Okay.

[00:02:56]Um we've got a control and a caps lock.

[00:02:58]So, I'm thinking this might be perhaps a home brew keyboard for a western western computer.

[00:03:07]Although again, it's only got a five-pin DIN uh which would indicate a serial protocol rather than a kind of a keyboard matrix.

[00:03:18]So, yeah, I I don't know. That's why I thought it'd be interesting to to have a look at. Um we'll figure it out together.

[00:03:27]Uh so, we've got screw screws.

[00:03:31]Let's see. I'll open it up and um we'll try to figure it out. Okay, I think the top All right, top comes off.

[00:03:40]All right.

[00:03:44]We've got ROM. We've got an 8255. We've got an 88 Okay, so this appears to be a computer.

[00:03:52]But uh how does it get an expansion port? The I have no idea what this is. All right.

[00:04:00]Um definitely looks homemade.

[00:04:03]Let's All right, let's get this. Going to get the power cable through.

[00:04:09]Doesn't look like there's any There's no Oh, we've got the good capacitors. We've got the KM types, the green KM types. I love these capacitors.

[00:04:19]Um they have um platinum, palladium, silver. Sorry if that made a noise on the microphone.

[00:04:30]Um so, quite often, I think that's what also drew me to this machine is that it had the um these KM type Be careful the sides here, but KM type capacitors.

[00:04:44]Quite often, you'll see them stripped out.

[00:04:46]So, they're being used as decoupling capacitors here because of the uh scrap value. So, you'll see them cut out, which is annoying.

[00:04:54]Um to me, sorry, I just need to sneeze. So, to me, um it's the computer's the scrap value of this is a lot less than the computer is worth.

[00:05:06]But, you know, it is what it is.

[00:05:08]Love them. Perfect. I love all these capacitors.

[00:05:12]Perfect. Okay. So, we've got a Trying to figure out what this power power in.

[00:05:21]So, we've got I don't know if you can see it. It's a Is it KRE 4? So, it's like a the Soviet 7850, 7805 5-V regulator. So, to me, that means this is definitely not AC in.

[00:05:39]Maybe.

[00:05:40]I think maybe it comes from Maybe there's an external Maybe there's an external um Okay. All right. So, what do we got here? We got a line. Okay. So, oh okay.

[00:05:52]So, this there'd be some external power supply block Britannia.

[00:05:57]Uh power block.

[00:05:59]Okay.

[00:06:00]>> [laughter] >> That it was connected to.

[00:06:03]Um and I would say this is also a video output as well because if you look at this DIN connector here, it's only got three connections. So, this would be for tape magnetophone.

[00:06:15]So, power power and um and video output are all coming through this.

[00:06:23]Excellent. That's going to make things interesting.

[00:06:27]So, what uh the ROMs? We've got Oh, okay. We've actually got three ROMs. Little piezo piezo right there.

[00:06:39]Um So, whether it's an So, let me just Let's have a closer So, there's two main kind of homebrew designs that I'm vaguely familiar with. There's the radio 86RK um and then there's the specialist. So, the main difference in my limited understanding is that the um 86RK used, for example, the 8275 CRT controller 85 8257 DMA controller or the Soviet equivalents.

[00:07:12]Uh so, it's kind of like text only.

[00:07:14]Whereas, the specialist um used its own discrete logic for for video output. So, it actually was capable of graphics. That's a very simplistic view.

[00:07:25]So, what we what we can see here is we've got the Let's maybe go this way.

[00:07:33]So, we've got the KR580VM80A, which is the Soviet uh 8080 clone.

[00:07:40]Then we've got this one here, the KR580VV51A.

[00:07:45]I don't know what that is. Maybe that's So, that would off the top of my head, 8251 Intel. I don't know what that is off the top of my head.

[00:07:53]Um then we've got we want to move the little speaker a little bit.

[00:07:59]Um KR580 uh VI53.

[00:08:03]So, that'll be an 8253.

[00:08:06]Is that a PIT, programmable interval timer? I can't remember.

[00:08:10]I'll have to look it up. KR580VV55A.

[00:08:13]So, that's an 8255 programmable peripheral interface. So, like for keyboards or for interfaces there. And we've got some more boards under uh some more CPUs there.

[00:08:27]So, what do you reckon? Um all right, let's have a look. What are these?

[00:08:32]So, RIT M, RITM.

[00:08:37]Uh what is that?

[00:08:40]K LAV, KLAV.

[00:08:46]KLAV uh keyboard.

[00:08:48]It's a KLAV KLAV something is a keyboard or something.

[00:08:52]RITM.

[00:08:53]KLAV. So, uh I have no idea what this is. So, it's got a CPU.

[00:09:00]It's got a cassette interface.

[00:09:02]And I'm guessing it'll have some sort of video output here.

[00:09:07]Again, oh, I love those. Love those capacitors. It's KM type capacitors.

[00:09:13]If um if you're ever looking at a Soviet-era computer and it doesn't look like it's got any decoupling capacitors, it's probably because they're all been snipped off.

[00:09:23]Not a big problem. You can just replace them with 100 nanofarad, but it's always nice to have these original capacitors.

[00:09:31]Right. So, I think I'm going to have to get this off to have a look at what those other chips are.

[00:09:36]And then I'm going to have to figure out here what signal is what.

[00:09:43]So, I could probably run it off DC.

[00:09:47]Just put in say 9 volts or 6 volts so that the 5 volts is generated by the regulator.

[00:09:55]Um but yeah, for video output, well, I'm going to have to get the oscilloscope out, I think.

[00:10:00]I've got the side off and I'm just looking at these again. So, these I thought initially were just LEDs, but they actually appear to be indicators of some description.

[00:10:09]Now, interesting. So, I've got that.

[00:10:12]Oh, no, it's soldered on, of course.

[00:10:15]Let me just um I'm just looking at the uh the ROMs.

[00:10:18]There are actually two pairs piggybacked.

[00:10:22]So, that one I'll be able to dump cuz obviously socketed. That one's going to be a bit of a pain cuz I need to desolder it.

[00:10:29]Um but I'll also try to figure out what this pinout is um on the cable wherever the end of it went.

[00:10:39]Oh, there.

[00:10:40]Try and figure out what that is compared to that so I can power it and um check what signals are coming out.

[00:10:50]How interesting.

[00:10:52]What a mystery. So, actually one thing that makes um figuring these old Soviet machines out is their insistence on using color-coded wires so that you can tell which wire is which.

[00:11:04]>> [laughter] >> That's all part of the fun, isn't it?

[00:11:08]All right. I have made some progress uh but I'm a bit stuck. So, 8080 is a tri-voltage chip. So, we've got uh plus minus 5 volts and plus 12 volts.

[00:11:23]That there is an 8224 clock generator.

[00:11:25]So, that also needs 12 volts. So, uh the problem is all right. So, obviously the thicker wires are going to be power input and I have traced as much as I can.

[00:11:41]So, the red one is the regulator input, so that is a if I can read it again, it's a basically a 7805, so that's a KRE N5A. So, pin one is the input.

[00:11:53]Middle pin is ground and then that pin is the 5-V regulated output.

[00:12:00]So, that's all fair enough.

[00:12:02]So, red red is the regulator input.

[00:12:08]Black is ground, obshcher.

[00:12:11]Zemla, sorry, I can't pronounce it right. Blue is number seven.

[00:12:20]And green is plus 12 V. So, green is definitely connected to what was it? Pin 28, this one here.

[00:12:30]So, that's definitely 12 V.

[00:12:32]Um the blue one is not -5 V in as far as I can tell because it's not directly connected to pin 11.

[00:12:44]It goes via Let me I think maybe let's let's put this and I'll move the PCB around here a bit better.

[00:12:51]So, where's my poker?

[00:12:52]Right.

[00:12:54]So, we've got pin 11.

[00:12:56]Um that's -5 V, pin 20 is +5 V and then pin 28 is +12 V.

[00:13:03]So, definitely pin 28 is connected to this green input here. So, we've got +12 V coming in.

[00:13:12]And we've got the regulator input, whatever voltage that is.

[00:13:16]I would, you know, why not just use the 12 V in?

[00:13:20]I don't know, maybe generates too much heat, I don't know.

[00:13:23]>> [sighs] >> So, I'm not sure that is that's ground.

[00:13:25]And then the blue one So, the blue one is connected to Let me just move that.

[00:13:33]is connected to post number seven here.

[00:13:38]So, post number seven then goes kind of across here. It goes via these, I think, diodes. I don't know if these are like zeners or something.

[00:13:46]So, on the um Sord M68000 that we were looking at yesterday, they generated the -5 volts for the 8080 from -12 volts, +5 volts, and a zener which clamped the voltage to -5 volts, and then we had um a couple of resistors and a uh electrolytic.

[00:14:08]So, I don't know if this blue is supposed to be -12 volts, and then we're generating -5 volts via this circuitry, which eventually ultimately ends up at pin 11.

[00:14:26]And Matia, I don't understand. I'll have a closer look. Hopefully, this is a bit bit of a better look. So, that's pin seven there. That's the that's the input that then goes across to these diode-looking things here.

[00:14:45]I don't know if this is I don't know what these are.

[00:14:48]Could be a zener.

[00:14:49]And then ends up over on pin 11.

[00:14:55]There's our clock generator there. So, that also that needs to be running obviously for that to run. And obviously, the crystal here needs to be working anyway.

[00:15:07]So, that's where I'm at the moment. I'm a bit stuck. I don't have I do have I have designed a kind of a specialized universal power supply, but I don't have any -12 volt regulators at the moment.

[00:15:18]They're on back order.

[00:15:19]So, I'm a bit wary of trying to power this up without that. So, that's that's where I'm at the moment. Does it make sense?

[00:15:28]No? I know. Oops, sorry. I didn't mean to put my fingers there.

[00:15:32]Uh and these are the ROMs again. If we have a close look, so written r t r i t m clav, so that'll be keyboard. And then we've got a k 9719.

[00:15:45]How's that?

[00:15:46]That's n, isn't it? That's not i, that's n3.

[00:15:50]The the confusing for me anyway mixture of Cyrillic and then Latin.

[00:15:55]And then we have k b 470 n2. So, I think maybe k maybe for checksum checksum. So, maybe this is the checksum for the ROM.

[00:16:06]And then we've got um piggybacked and also piggybacked there, but that's soldered in. So, if there is interest, I will try to dump those ROMs.

[00:16:19]Um you can see there probably that's the chip select.

[00:16:22]Uh which goes via comes out of there, so maybe some sort of decoder there.

[00:16:29]So, yeah, I'm I really don't know what this is.

[00:16:34]I It appears to be some sort of computer using a QWERTY layout.

[00:16:39]So, maybe some sort of I don't know ham radio ham shack computer.

[00:16:45]If anyone has any idea, I would be grateful.

[00:16:48]But yes, that's where I'm at. So, I'm going to try and figure out those voltages. Once I get those negative 12-V regulators, then I can try and power it up um cuz I've only got plus 12 plus minus 5-V power supply at the moment. I don't have the negative 12.

[00:17:03]Okay?

[00:17:04]Thanks for sticking around. Bye for now.