Elektronika DVK-3, a Soviet PDP-11 clone micro

[mrcity]

Hello Comrades

A while back, I contacted Mihail via the email address shared in this old "For Sale" post http://www.vcfed.org/forum/showthread.php?57786-Soviet-DVK-3-PCs-available . Anyway, I guess the closest domestic thing to it is the DEC PRO 325 & 350. After probably 2 months back and forth of figuring out if it works, how it works, what comes with it, what can I do with it, how much it all costs, and how to pack it so it doesn't get destroyed, I finally took the bait and got one. Its 150-lb crate arrived at the corner of my front yard last Tuesday, leaving me to haul it up nothing but hills with my hydraulic lift cart. :nervous:

Here are some pictures:


The huge crate


Original packing materials (even the styrofoam)


The computer


Physical documentation

I haven't had a chance to power it on (or even really rip it open yet), and am still thinking of the best way to get it the 220V (+22, -33) @ 50Hz it needs (or if it can live with 60Hz). It has a CEE 7 or GOST 7396 style plug on its power cable, and a separate input for ground. I was thinking of getting a 120VAC -> 12VDC converter, and then another 12VDC -> 220VAC @ 50Hz converter. However, one of my friends suggested that a cheap 220VAC converter might only serve up square waves, which has a slight chance of aggravating a power supply expecting sines. Also, there's been discussion as to whether the two CEE 7 plug pins are supposed to be hot & neutral, or two split-phase hot lines. I'll really have to open it up and take more photos.

Anyway, Mihail has shared with me a PDP-11 emulator configured as a DVK-3, even more digital documentation, and even a forum post about an SD card FDD emulator. The ST-412 hard drive made it through customs, but not the floppy disks, because they were concerned that encrypted data might live on the floppies, though no one had a way to test it. My best bet for now is probably to load things to it over a serial connection.

I'm glad this deal went down so well and that the artifact didn't take any cosmetic damage in shipping. I was especially worried about the CRT, as one I ordered once got broken coming from just California, but Mihail hand-made a really strong crate to protect everything and preserve the original packaging, so now I have...this wonderful piece of eye candy for now.

 

[krebizfan]

Lovely system. So how much lighter is it than the Pro 350?

 

[cthulhu]

60 Hz power should probably be just fine. It is in most cases as long as the equipment being powered doesn't need a particular frequency to run at its intended speed, i.e. certain types of motors. Transformers tend to work just as well if not better at higher frequencies, within reasonable limits at least. People run 50/60 Hz gear at 400 Hz in the aviation and aerospace industries all the time without issue. Running 60 Hz equipment at 50 Hz has been known to be a problem though, but only for the rare things that run right on the edge of stability, i.e. poorly designed stuff.

 

[shattered]

Nice!

Looking at the pics Mihail posted earlier, you've got a setup with CPU board that's capable of running UNIX (the 1201.03), a "MX" floppy controller (part number 7.102.617 silkscreened on the board) and color graphics board. Getting floppies written is going to be a fun exercise -- the controller is nothing like a PC one, but luckily, HxC supports its format -- http://torlus.com/floppy/forum/viewtopic.php?f=19&t=1384

There are forums you may find useful -- http://zx-pk.ru/forums/66-dvk-uknts.html for starters.

 

[mrcity]

Lovely system. So how much lighter is it than the Pro 350?

I've never picked up a Pro 350, but I estimate this guy weighs about 30 lbs. The monitor is as deep as the whole system, and while the CRT screen isn't much bigger than my outstretched hand (as figured from Mihail's pictures), the bezel is enormous, making for a much larger monitor than I expected. (Edit: I wanted to also say that the computer is about 16" wide, 18" tall, and 20" deep.)

the controller is nothing like a PC one, but luckily, HxC supports its format

Great! That's useful information, and I have an HxC controller. Now to find disk images and the correct power. I figured 60Hz would be fine based on what I've been reading as well, as long as the monitor doesn't generate its sync signal off the AC or something like that.

 

[cthulhu]

Great! That's useful information, and I have an HxC controller. Now to find disk images and the correct power. I figured 60Hz would be fine based on what I've been reading as well, as long as the monitor doesn't generate its sync signal off the AC or something like that.

Monitors don't have a choice, they have to sync to the video signal. I've never seen the video signal timing derived from the AC frequency but I suppose stranger things have happened. The Commodore 64 uses the AC frequency to generate the TOD clock. Fortunately very, very few programs (I know of only one) actually use that clock.

 

[shattered]

Great! That's useful information, and I have an HxC controller. Now to find disk images and the correct power. I figured 60Hz would be fine based on what I've been reading as well, as long as the monitor doesn't generate its sync signal off the AC or something like that.

Check the board set just to be sure -- there was another, PC-compatible, controller as well.

 

[mrcity]

I finally have the computer disassembled all the way. Here are my findings on the power supply and the board set:

https://photos.app.goo.gl/OTygMNFjGZHzplRF3 - Power supply (including a video toward the end, covering every angle)
https://photos.app.goo.gl/cTFki2yPs8VyjJQF2 - Board set

And if any of you can read Russian, here are forums with documentation for the power supply: Forum 1 and Forum 2 I'm going to peruse these with someone who knows a thing or two about power supplies just to make sure I don't blow anything up on the first pass.

 

[Terri Kennedy]

I finally have the computer disassembled all the way. Here are my findings on the power supply and the board set:

That seems to be a pretty weird memory layout on the board with the CPU (КМ1801ВМ3) - there are 4 rows of 11 64K chips (КР565РУ5). One of the other boards (with 3 blue headers) has a more normal arrangement of 2 rows of 9 КР565РУ5. Unfortunately, I can't make out the part numbers on some of the other white ceramic parts (low resolution / contrast).

I've powered some other Soviet stuff (mostly Elektronika 7 clocks) with a Goldsource STU-300. That model (300W, supposedly) seems to be discontinued, but other STU models still seem to be available.

 

[Sandisk78]

Hi ! I think I can help. I have friends here, who work with these DVK retrocomputers - so called "REtrocomputer_Club of people who like Soviet/Eastern Block machines " - they can make a controller to boot DVK3 from a modern SD card)

here are my pictures of that place in 2012 -

https://imgur.com/a/dZYbE

and some collectors also... I'm going to buy a DVK3m, too.... )

 

[shattered]

I finally have the computer disassembled all the way. Here are my findings on the power supply and the board set:

OK, you do indeed have a "MX" floppy controller and a color graphics board (firmware revision 181 -- earler, and buggy one). What type of floppy drives did you get?

That seems to be a pretty weird memory layout on the board with the CPU (КМ1801ВМ3) - there are 4 rows of 11 64K chips (КР565РУ5). One of the other boards (with 3 blue headers) has a more normal arrangement of 2 rows of 9 КР565РУ5. Unfortunately, I can't make out the part numbers on some of the other white ceramic parts (low resolution / contrast).

8 data bits + 3 ECC bits -- К555ВЖ1 chip in the center is a LS630 clone.

 

[mrcity]

I have friends here, who work with these DVK retrocomputers - so called "REtrocomputer_Club of people who like Soviet/Eastern Block machines "

Heh, that is quite the group name... No one will ever misconstrue what they are about! It's good to see that there is a healthy interest in retro computers in Russia. Maybe you or one of these fellows could help me fix my hard disk controller. Mihail claims I will have to remove it, or else memory check failures will cause the system to not boot. I would appreciate it!

I believe this is the error screen it will show: https://drive.google.com/file/d/0ByRamH3wFb6SZWVyT3JzeElxMjA/view?usp=sharing Maybe I could use the piggybacking technique to help weed out the errors.

Also, tell me about the DVK 3M - does it have a full color monitor? I've only seen apps run in one color on it.

I've powered some other Soviet stuff (mostly Elektronika 7 clocks) with a Goldsource STU-300.

I think that one came up in my search on Amazon recently, but it wasn't clear to me if it could convert 120/60 to 220/50. Someone is looking at the documentation for me, particularly section 3.5.6 of the power supply manual where evidently it states "The unit provides for the possibility of external synchronization of the master oscillator of voltage converters with a horizontal scan rate of 15.4 kHz".

What type of floppy drives did you get?

Two of this kind, the MC5305:

Also, 22 seems to be a "reserved word" around these parts. I didn't realize the 74LS630 was a thing -- hadn't really ventured that high in the 74-series logic family -- but my assumption was the odd arrangement of RAM chips would have been to support the 22-bit physical addresses that can be used by the КМ1801ВМ3: http://www.155la3.ru/datafiles/km1801vm3.pdf However, I think that devoting all 22 chips for an address would defeat the purpose of installing these EDAC chips, not to mention risky from an electrical error perspective. And thanks for all the rest of that good information.

I might post better pictures of the ceramic chips, but also figured Mihail took some pretty decent shots to begin with: https://drive.google.com/drive/folders/0ByRamH3wFb6SYU1kclZQNWxkQUU

 

[mrcity]

Oh, I forgot to mention, for those of you who want to play along at home with the Russian PDP-11 and KM1801BM3 goodness: there's an emulator for Windows (for lots of DVK systems, not just the 3) that Mihail provided me at https://www.dropbox.com/s/oiecbqlichl1p1m/ДВК-3.7z?dl=0 . I don't know what the original source is, but it contains docs and a PDP-11 emulator with the configs for this processor. Since my Windows version didn't take too kindly to Cyrillic characters, I had to rename ДВК-3.cfg to DVK-3.cfg and update the reference to that file in the pdp11.ini file so that it would stop complaining to me about a missing config file.

Once you get it running (and you might need to toggle Num Lock if you're like me and using a laptop with shared alphabet/numpad), it's pretty easy to load up Tetris. :D The fun part is finding the mapping of Cyrillic to Latin characters on the keyboard, since unfortunately the Cyrillic phonetic sounds don't map to the Latin characters as we see them on ours. Nevertheless, this picture of a keyboard will help: https://drive.google.com/file/d/0ByRamH3wFb6SbFNLWmZrYVhMQ2s/view

 

[shattered]

Oh, I forgot to mention, for those of you who want to play along at home with the Russian PDP-11 and KM1801BM3 goodness: there's an emulator for Windows (for lots of DVK systems, not just the 3) that Mihail provided me at https://www.dropbox.com/s/oiecbqlichl1p1m/ДВК-3.7z?dl=0 . I don't know what the original source is, but it contains docs and a PDP-11 emulator with the configs for this processor. Since my Windows version didn't take too kindly to Cyrillic characters, I had to rename ДВК-3.cfg to DVK-3.cfg and update the reference to that file in the pdp11.ini file so that it would stop complaining to me about a missing config file.

Once you get it running (and you might need to toggle Num Lock if you're like me and using a laptop with shared alphabet/numpad), it's pretty easy to load up Tetris. :D The fun part is finding the mapping of Cyrillic to Latin characters on the keyboard, since unfortunately the Cyrillic phonetic sounds don't map to the Latin characters as we see them on ours. Nevertheless, this picture of a keyboard will help: https://drive.google.com/file/d/0ByRamH3wFb6SbFNLWmZrYVhMQ2s/view

Source for the emulator is http://zx-pk.ru/threads/18351-emulyator-dvk.html -- it is under active development. It's not the only one + yours truly is working (on and off) on MAME driver for DVK series. Preview:

( Your setup should be able to run that )

 

[cthulhu]

I think that one came up in my search on Amazon recently, but it wasn't clear to me if it could convert 120/60 to 220/50. Someone is looking at the documentation for me, particularly section 3.5.6 of the power supply manual where evidently it states "The unit provides for the possibility of external synchronization of the master oscillator of voltage converters with a horizontal scan rate of 15.4 kHz".

This doesn't sound like it has anything to do with the AC line frequency though. I'd be really surprised if anything like this, i.e. a non-consumer high-end computer, has any issues at all with being powered at anything between 50 to 60 Hz. And as I mentioned in an earlier post, even 400 Hz power should be perfectly fine too.

 

[Terri Kennedy]

I think that one came up in my search on Amazon recently, but it wasn't clear to me if it could convert 120/60 to 220/50. Someone is looking at the documentation for me, particularly section 3.5.6 of the power supply manual where evidently it states "The unit provides for the possibility of external synchronization of the master oscillator of voltage converters with a horizontal scan rate of 15.4 kHz".

No, it only does voltage conversion, not frequency.

 

[shattered]

Technical manual specifies input voltage 220 +22/-33 V and 50 +/- 1 Hz. Forum post that links to this manual (http://forum.maxiol.com/index.php?showtopic=5158) also recommends to fully recap it. (I am not an EE expert, though -- ask someone who is)

MC5305 is a DS/QD drive, formatted capacity on MX controller will be 440 KB (it uses FM encoding).

CM5508 hard disk is a Bulgarian near-clone of ST-412 (see http://oldpc.su/articles/hdd/hdd.html). That article warns that heads may stick to the platters and recommends 'shaking' the drive before powering it on.

 

[Terri Kennedy]

Technical manual specifies input voltage 220 +22/-33 V and 50 +/- 1 Hz.

The Elektronika 7-06K clock manual says the same thing, except 220 +/- 22V. This is probably some standard boilerplate, just like old (tube) radio manuals in the US said 117V, even though that was never really a standard.

Even more amusing, the 7-06K has jumpers on the transformer to reconfigure it for 110V:

The smaller Elektronika 7 clock doesn't have those jumpers.

 

[mrcity]

I took just the power supply over to the local makerspace, which has an APT VariPlus 105 AC power converter, and I verified the voltages on the PSU! No "АВАРИЯ" ("accident") light, yay! My +5V reads +5.3, +12V is +12.3, and -12V is -12.1. I'm sure that when I add the components back in and restore the load on the PSU, it'll drop that +5V to back within tolerance. I also went through all the pins (not just the test points) and was impressed that only two of the DC output pins had 0.02V of ripple; the rest showed no AC ripple at all on the true RMS multimeter.

Yours truly is working (on and off) on MAME driver for DVK series. (Your setup should be able to run that ) -- and other good points

Wow, that'll be cool! I can't wait to take it for a spin. I guess that explains why you know so much about the hardware.

I didn't see any obvious issues with the capacitors (i.e. bulges or leaked electrolytic goo), so I left them alone. I'll have to fix the clackety fan before I even have a chance at hearing if there's whistling. I've never even come across DS-QD disk equipment (even after picking over a guy's warehouse with NIB 8" floppies and drives), so I really hope Mihail can get the media he has past customs and to me. As for un-sticking old MFM drives, it's something I'll need to practice. I certainly have some lined up in the queue. Maybe that's a class idea for the local makerspace.

I'd be really surprised if anything like this, i.e. a non-consumer high-end computer, has any issues at all with being powered at anything between 50 to 60 Hz.

Yeah, I think the power supply itself could handle it (in fact, it could even run cooler). There are still 3 signals I'm not sure of where they are coming from, but that get transferred through PSU pins: Ии∂.осм (си) (elsewhere written as Ии∂.ост (си)), КПРТ, and Осм. These are abbreviations but my translator didn't know what they stand for and my quick Google searches didn't turn up anything. Nevertheless, they show up on pages 2 and 3 of http://forum.maxiol.com/index.php?act=Attach&type=post&id=8291. It's doubtful they relate to the PSU, since on page 3 they are probably shown as inputs that just lead straight back out, but it'd be nice to know for sure. I suppose I could take it back to the makerspace and try the 60Hz mode on the power converter once it's back together to make sure it'd work OK after getting a feel for how it works at 50.

Even more amusing, the 7-06K has jumpers on the transformer to reconfigure it for 110V.

Heh, if only... I'll have to go over it carefully to see if it has that. However, I doubt it; the Soviets made certain things for export and I doubt this was one of them.

 

[shattered]

There are still 3 signals I'm not sure of where they are coming from, but that get transferred through PSU pins: Ии∂.осм (си) (elsewhere written as Ии∂.ост (си)), КПРТ, and Осм. These are abbreviations but my translator didn't know what they stand for and my quick Google searches didn't turn up anything. Nevertheless, they show up on pages 2 and 3 of http://forum.maxiol.com/index.php?act=Attach&type=post&id=8291. It's doubtful they relate to the PSU, since on page 3 they are probably shown as inputs that just lead straight back out, but it'd be nice to know for sure.

Two of these three originate on the front panel:
- "Ост" is sent by "ПУЛЬТ" button and goes to the HALT line on the bus. This causes CPU to go into "HALT" mode and run ODT.
- "КПРТ" enables line clock interrupt via BEVNT bus signal.

"Инд. ост (СИ)" -- external sync source for the PWM mentioned in the manual ("The unit provides for the possibility of external synchronization of the master oscillator of voltage converters with a horizontal scan rate of 15.4 kHz".), likely unused.