Cold wind from the USSR visiting the Electronics Room tonight

[mrcity]

I just got my hands on an old Электроника ДВК-3 (Elektronika DVK-3) from 1989. It’s a PDP-11 clone microcomputer. I haven’t powered it on yet because i haven’t run it through my usual inspection, plus it needs at least 2 amps of 220V @ 50Hz, not 120V @ 60Hz, not to mention its weird Russian power prongs and separate ground wire (like on old stereo receivers). Come check it out and if you’re so inclined, help me power it on (or at least make a suggestion on the best way to convert US voltage cheaply!)

Oh, and if you think you’re gonna find anything related to certain politicians on it, there are no floppy disks with it and I don’t know how to mount the hard drive (or if it even works). ;). All we’ll do, if even possible, is just see the screen light up.

Pics to come!

[ESmith]

This is possibly the DMS-iest thing ever.

[Photomancer]

@artg_dms Well Art, you’re becoming Comrade E-labs Chairman. You need at least a couple ribbons with stars on it. Maybe we could dye-sub you a tee-shirt with that on it.

[ESmith]

Go fetch yourself a Hero of the Soviet Union from petty cash.

[Raymond]

He can make one…

Медаль "70 лет победы" / Jubilee Medal "70 Years of Victory in the Great...

[richmeyer]

The Electronics Lab has a 220V, 50 Hz power source. Used the APT 105 Power Supply that is sitting on their shelf. I believe it can handle up to 3 1/2 Amps. It even accepts some international power cords. The User Manual is up on the shelf above the computer. Give it a try.

Have a good bottle of Vodka standing by when you power it up.

[Bill]

If you hook it up to the Internet, will it default to .commie and .nyet domains?

[ESmith]

Pretty sure the USSR never embraced the .su iTLD they were assigned…

[Photomancer]

Make sure the video camera has a clear view - love in house movies!

[electron_pusher]

I strongly suspect the power supply is a switcher. Look over the power supply board and see if the power input has a diode bridge and filter cap (possibly after a voltage doubler or tripler). If so you can easily determine the high voltage rail needed to drive the switcher and feed it from a high voltage dc supply. With appropriate caution for high voltage, that would neatly evade any issues of overheating a 50 hz rated transformer or differences in hot-neutral to split phase wiring. If you can lay your hands on a variac that has a VA rating at least 40% over the watts required to run this beast it will simplify making a quick and dirty adjustable high vdc to feed the switcher. I’ll be down at Oz’s matlab class tonight. I’ll bring a bottle of corona dope in case you want to pursue this.

[mrcity]

Hey Steve, thanks but not tonight; I usually try to keep Fridays low-key and low-energy, and shut off my brain for a few hours.

Anyway, I promised I’d post pictures, and since only a few of you saw it in person: (note the original packing materials sitting on top of it in the first picture, and the documentation in the third picture)

[Hammerson]

I hail from the same soviet region as the tech. Let me know if you need an assist reading Cyrillic.

[mrcity]

Sure, I would love to take you up on that offer! I got the whole top part taken apart, but am still trying to crack open the bottom part to learn more about the power supply. I have “djvu” (PDF-like) documentation that’s 95% likely to be for this power supply (and general theory of the computer anyway, including all the GOST regulations it complies with), but I’d like to verify it for sure.

Despite that the document says it must run at 50 ±1 Hz (that part is pretty obvious without knowing Cyrillic ) , it’d be nice if someone familiar with power supplies could reassure me that it’ll take 60 Hz (most people think it’ll be fine with 60 anyway) and/or work with the supply @richmeyer mentioned.

For now, I’ll have to deal with this thing that likes to refer to a power supply as “block food”… it’s a long time until machines will take us over

[Raymond]

I have to wonder if the 50Hz requirement is for some clock or other timing…

[Hammerson]

Send the djvu to daniil.marchenko at gmail.com I’ll take a quick look and see what I can translate about voltage and hertz ratings.

[mrcity]

Thanks, Daniil, for your early insights into the documents! I have totally ripped apart the system now, and have taken lots of pictures (and video) of the guts:

https://photos.app.goo.gl/OTygMNFjGZHzplRF3 - Power supply (video is toward the end)
https://photos.app.goo.gl/cTFki2yPs8VyjJQF2 - Board set, including floppy disk controller, hard disk controller, video card, and motherboard

I can bring it in if anyone is interested and we can look over the power supply in person, and possibly hook it up to the plug in the E-Lab and test the voltages coming from it.

[dejswa]

I don’t recall ever seeing a switching power supply from that era. I’m guessing that was late 70’s.

And there is a good possibility that it may function at 60Hz. Overheating would not be the problem running at 60 Hz but reduced power might be.

[mrcity]

I’d love to make it a guessing game, but just to help out with understanding this piece, I’ll say it was built in:

(Get your best guess in before reading the spoiler!)

1989

With that, there seems to be structures in there resembling diode bridges… Also if I recall correctly, the +5V line maxes out at 24A, the 12V at 15A, and the -12V at 1A, so that means (assuming the negative voltage isn’t treated differently) that we’re looking at 312 watts, or less than 1.5A at 220V (despite there are two 4A fuses in the PSU…).

[mrcity]

I was able to power it on without vodka (but with Todd standing by manning the defibrillator ) and, indeed, I verified the voltages! What a super-cool piece of test equipment the APT 105 is. Now to rebuild the really noisy power supply fan, rebuild the system, and actually power on the whole thing at once…

[mrcity]

IT’S ALIVVVVVVVVVE!

I didn’t know what to do at first. After I got home, I watched some of the videos Mihail posted on using it, and learned the command you write in order to get it to do anything (namely, even enter RT-11 in the first place). I’m not really sure what mode it boots up into, but you have to type B and then MY0 for it to enter the program in its ROM. (MX_n_ is for other I/O devices.)

Now, to get the floppy disks for it…