Restoring my old Soviet radios

[paulsherwin]

The Selena plug appears to be rewirable. The examples we see here in Europe are always moulded onto the cable and are notorious for developing faults. Being moulded, they are impossible to repair, so there is a great shortage of Selena mains cables.

[Miguel Lopez]

You're right Paul, it is rewirable, and in that case, it is rewired, as I had to replace the cable. All Selena mains cords in Cuba were rewirable, AFAIK, and they also failed everytime, but they could be fixed.

[Miguel Lopez]

Here my new radio adventure. This time it is a Siboney, ......or two of them, but the purpose is to get one of them restored in the end. The good thing is that I have given them a look and the parts that are broken on one set, are OK in the other, so I think I can make an hybrid to reach my goal. Siboney is a Cuban copy under license of the Soviet Spídola 231 (or 240, not sure). As most Soviet radios of that age, it uses Germaniums.

[SteveCG]

Thank you for the mains frequency info as well as the 220V point. With the 220 Volt option is it 0 - 220V or is it 110-0-110V (that is, both plug pins live)?

[orbanp1]

Hi Steve,

Here is a link to the Selena B-216 schematics:
http://www.eserviceinfo.com/download...na%20B216.html (It is in three pieces.)
As you can see the mains transformer has a 127V tap.
In another schematics of the same radio shows 2x110V windings for the mains transformer, they probably came in both versions.

The B-215 is the same radio as the 216 except the FM band covers the CCIR frequencies while the 216 has the OIRT FM band:
https://en.wikipedia.org/wiki/FM_broadcast_band

Peter

[dave walsh]

Hi Miguel. I'm wondering if the current change in the relationship with your country's immediate neighbour will now make things easier for you re getting parts etc in and out of Cuba? I presume that Russian sets have been predominant for sixty years! Are there pre-revolution radios and other electronic items in existence along with your fantastic vintage cars? Is there a large radio/tv repair industry?
Best Wishes,
Dave Walsh

[Miguel Lopez]

Originally Posted by SteveCG

With the 220 Volt option is it 0 - 220V or is it 110-0-110V (that is, both plug pins live)?

110-0-110V with both plug pins live.

Originally Posted by orbanp1

except the FM band covers the CCIR frequencies while the 216 has the OIRT FM band

Not 100% exactly, as all B216 in Cuba cover 88 to 108 MHz.

Originally Posted by orbanp1

In another schematics of the same radio shows 2x110V windings for the mains transformer

That is the case in my brand new Selena.

Originally Posted by dave walsh

will now make things easier for you re getting parts etc in and out of Cuba?

Not sure about that. There weren't components shops in Cuba during the Soviet era, when everything was abundant, so I don't think that it is going to be diferent due to the good relationship with the US.

Originally Posted by dave walsh

Are there pre-revolution radios and other electronic items in existence

Very, very few. People dumped most of them. Really sad. I don't know even about a museum to preserve such stuff in Cuba.

Originally Posted by dave walsh

along with your fantastic vintage cars?

Yes, they are fantastic, but vintage? just in appearance. Most od them fit Japanese, Korean or European modern diesel engines, and modern mechanics from any corner of the world.

Originally Posted by dave walsh

Is there a large radio/tv repair industry?

there are assembling plants for foreign product such as TV sets, and more recently digital TV decoders. During the 90s there was a solid state components plant which manufactured excelent components. I ignore the reason why that plant stopped working. Before that, there was an assembling plant for Eastern bloc radios and TV sets. (such as the Siboney and the RITMO that I have presented on this thread)

[Brian R Pateman]

Originally Posted by Miguel Lopez

Yes, they are fantastic, but vintage? just in appearance. Most od them fit Japanese, Korean or European modern diesel engines, and modern mechanics from any corner of the world.

Just a gentle reminder that discussion of motor vehicles - even in Cuba - is Off Topic for the forums.

[dave walsh]

Noted Brian I've never been into motors, I was just trying to be complementary. Thanks for the replies Miguel. I suppose any early sets that are around could be valuable at some point although I did once see a documentary re getting pianos into your country for young musicians. It seemed that your otherwise favourable climate+Termites? turned their woodwork into a sponge in no time at all. We sometimes find wooden cased radio sets in the UK that are riddled with woodworm holes but nothing like the Cuban piano experience! Your English seems to be better than can be expected from the average Brit these days.
Dave

[Miguel Lopez]

Originally Posted by dave walsh

It seemed that your otherwise favourable climate+Termites? turned their woodwork into a sponge in no time at all.

Termites have always been a problem in Cuba. Most vintage electronics stuff which had wooden pieces were always "attacked" by termites. Soviet TV sets such as Electron and Krim being the main targets, but they also attacked valve radios, speaker cabinets, record players, and to a less extent, Selenas. I think as the later is a portable device is less exposed to termites.

Back to the radios.

I have fixed the electronics in the Siboney (See pictures). Althought I try to use vintage Soviet GT402 output transistors which originally fits the Siboney, it wasn't possible. They seemed to be OK but when I switched on the radio, current increased unstoppable. I replaced them by a couple of BD140, and I did not notice any crossover distortion.

The problem is that while I'm listenning to the radio, the station seems to vanish (zero reception), then you move the tuning knob and the station is now tuned 5 or 6 mm away. A time later the process is repeated and the station in tuned where it was originally.

I guess that is due to any faulty capacitor which change the frequency in the local oscillator, but I still have to discover which one.

Has somebody had this problem before?

[Miguel Lopez]

The problem with the "jumping" stations is now solved. I replaced the MW PCB in the turret switch by the one from the second set. This PCB has only a couple of trimmers, a 1K resistor, a coil and a fixed capacitor. One of them should be faulty. The radio is working fine now.

Today I intend to replace some ceramic capacitors which had broken corners, and then I will go on with the cabinet.

[ok1dpf tube]

Hi Miguel, I can send you some boards from Russian transistor radios on the components on them except for transistors and other components. You can also write an accurate list of which you seek, in the Czech Republic are fairly common these parts because my country was occupied by the Russians for a long time. Yours sincerely Peter OK1DPF

[Miguel Lopez]

Hi Peter, thank you for you offer. I'll think about it. Will answer you by PM.

************************************************** ****

Here is the Siboney already finished. It sounds very well. As I did in the other radios, I included a plug for the mains cord in the back cover. The PSU was installed in the batteries compartment; it consists of a transformer (of unknown origin) and a PSU PCB from a VEF206. I will keep the other set as spares.

As a curious detail I should say that this radio has the dial graduated in kHz for the MW band, but for all the SW bands, the dial is graduated in meters.

[Miguel Lopez]

I've been working on the Taíno-74 and it is now finished. I had to do several replacements. The first was to replace some parts of the cabinet. I openned some holes on the original cabinet cause this radio was the target of several "research and improvement" projects during my early days as an electronic technician.

I also replace several capacitors and the output transistors. It originally fitted MP41 as outputs, but my stock of this old Soviet germaniums got exhausted with the other restoration projects, I had to use MP26, which has less gain but stand more power. Gain is not a problem cause the output gets saturated before the volume control reach its max.

I have a special appreciation for this radio as it is the first that I had. My mother gave it to me as a birthday present when I was 7 or 8 years old.

[Miguel Lopez]

I have "discovered" a very interesting thing while working with the Taíno-74 and the Juvenil-80. These two radios are Cuban copies of the Soviet, Orbita-2 and Radiotehnika 625, I have said before. Any schematic of the Soviet models that I have found, show 8 transistors. The Cuban copies fit only 7 transistors. Even the Taíno-74 front panel reads "7 transistors". I think one got lost while coming from the USSR to Cuba.

I think that missing one is that of the constant current source that Soviet radios usually had to bias the other transistors. The problem is that the diode of those constant current sources is present in the Cuban sets.

Any idea regarding this?

http://www.radiohistoria.sk/Oldradio...TA%20-%202.jpg
http://www.radiohistoria.sk/Oldradio...LE/Orbita2.pdf

[Miguel Lopez]

Finally I have finished the last of the family. The little Juvenil-80, which is very similar to the Taíno-74, but it can only tune the MW band. Tunning is very good as well as audio, for a tiny Soviet device. Here some pictures.

This one is the last of my Soviet radios, so I think this project is done. I'm very happy with the results and I hope that this work had been of your interest.

[Miguel Lopez]

The whole family together.