21 August, 2012

Fixing my Lithuanian oscilloscope

I visited Riga, Latvia with a youth group which we as a family were involved with in 1992, and there I stumbled upon a Soviet oscilloscope in a department store. It was from the neighboring country, Lithuania, and was manufactured in Vilnius, the capital. The markings say what I guess means "Made in the Soviet Union". At least it says CCCP in the upper right-hand corner. I remember these letters very well as all Soviet athletes used to have them on their backs.

The oscilloscope came with full documentation, even with a bilingual manual. I had grown fond of this oscilloscope as it was lightweight and simple to use once I had learned what the Russian markings meant. It is a typical instrument for TV-repair with a 7 MHz bandwidth.

Now after 20 years, I was therefore very sad when it malfunctioned. This was the time to test if the manual was helpful or not. The symptom was that the beam no longer could span the whole screen in the X-direction. Even with the Horizontal positioning all the way to the left one could barely see the beam.

I opened the bilingual manual only to discover that the two languages were Russian and Lithuanian!

But lucky for me, the schematic was similar to what I am used to and quite readable. It even contained PCB-layouts.

It showed two high-voltage transistors, KT940A, in the last stage of the horizontal amplifier. One of them turned out to have an open emitter-base junction. Specs that I could decipher from Russian data sheets on the web showed that KT940A is NPN, 300 V, 90 MHz. I found that I had a 2SC2611 lying around with similar specs. It even fitted the same footprint.  So now the oscilloscope is back in business again.

The oscilloscope is called Saga - осциллоскоп "Сага" - osciloskopas "Saga". It would be interesting to learn if this factory is still in business. Were they able to diversify into other areas in these very interesting last 20 years of independence for Lithuania, and indeed all three Baltic states, or have they vanished?



  1. Hello Sverre, great to repair such a device. At the top of the oscilloscoop is also the word oscilloscoop in Cyrillic and Сделано в СССР means made in the USSR. 73, Bert

  2. Oh yes, your Russian is better than mine. All I know is that CCCP is SSSR. When I put your sentence "Сделано в СССР" into Google translate it gives exactly "Made in the USSR" like you said.

  3. Hello Sverre, I took a course in Russian in 1994-1995, but I did not know enough words to develop myself further. But now we have Google translate for instant translation from many languages. Recently I used Google translate to study radio related expressions in Russian. After that I had great fun writing a Blog entry on the attenuators in Russian.
    You can translate to both Norwegian and English. hi
    73, Bert

  4. I love languages myself, but haven't gotten further than knowing most of the cyrillic letters. But it turns out that your blog when it sometimes is in Dutch is almost readable for me. With some German, some English and above all a background from Norwegian/Scandianavian it sort of works.

  5. Congratulations to the successful repairing, Sverre! I have an almost identical scope, the C1-94, this model was so "bulls-eye" in design, that French and German export version also existed. My friend, who's musician, borrowed it to check the tones and filter curves of analog synthesizers. I use on daily basis a Hungarian EMG-1564 (30 MHz) and Russian C1-83 (5 MHz). Both are very good machines!

    Greetings from Hungary: Zoltán

  6. Hi Zoltán,

    That's interesting. When I look up the C1-94 on the internet, I find an almost similar one with German text. Thanks for the information! I hope these oscilloscopes will last many years for you.

  7. Hi Sverre,

    "It would be interesting to learn if this factory is still in business. Were they able to diversify into other areas in these very interesting last 20 years of independence for Lithuania, and indeed all three Baltic states, or have they vanished?"
    I'm from Vilnius, Lithuania my self. It's sad, but "Vilniaus Spalio 60-mečio radijo montavimo prietaisų gamykla" or in english "October 60th anniversary plant of radio equipment assembly in Vilnius" is long gone.. I think they closed in 1993 or so right after our independency. In fact lots of our production factory's closed back then, may by it was due to decrease of market or may by our politics..

    As of the Osciloscope I have two of them my self. And one recently got broken. I don't have any of documentation left so may by you could scan the user's manual or at least the schematics of the osciloscope and send to me? I would be realy thankfull.

  8. Hi Aurelijus,

    Interesting but sad story, thanks for your comment.

    Let me know your email and I will send you a scan of the schematics, contact me on la3za at qsl.net

  9. Hi from Germany!
    Yes, you have the C1-94 (S1-94) oscilloscope. There is a ton of information on the russian internet on this model. And there are suggestions on how to improve the performance of the scope (published by a magazine in the 80´s or 90´s. Sorry i have no links, but search for "осциллограф с1-94" or "осциллограф s1-94" on google.

  10. Thanks for the tip.

    I tried and indeed I see a lot of hits. And with Google translate it is comprehensible in other languages than Russian also. My brief search did not bring out neither the full schematics nor the tips on improvement though.