From Rigonda with love

[Studio263]

I like sets which are unusual and technically interesting, which usually means B&O and Sony. One make which I’ve always struggled with though is Rigonda, and I suspect that I am not alone…

Rigonda sets originate from the USSR and were imported into the UK from the 1972 season until the late 1980s. Most were 4 1/2” monochrome portables of an advanced design sold at very low prices to earn much needed foreign currency for Mother Russia. At its announcement, the original VL100 model sold for just under £40 when a Japanese portable was between £60 and £80. The VL100 (and the subsequent and very similar Rigonda M) were replaced after a few years by a slightly larger set which used the same tube but incorporated a number of technical improvements, varicap tuning, intercarrier sound IC, slightly more “service friendly” layout etc. These were sold under both the Rigonda and Vega marques and came housed in neat metal cabinets painted in various dreary 3-year-plan colours. Later Vega sets came in a slightly bigger plastic cabinet, usually red (naturally…) or dog poo brown.

These sets come from a completely separate engineering culture to those from Western Europe and Japan, so the circuit designs and fault patterns differ to what one is normally comfortable with. The components too are quite different, most particularly the transistors. These are difficult to substitute, not least because they are of different physical sizes and shapes to our “normal” types.

Just recently I’ve bought a couple of sets, hoping to break my Rigonda duck. The first one is a really early VL100 (dated 1972 inside) but there’s quite a lot wrong with that so I’ll report back on that one later. The other is a Vega Shiljalis 402 D, which at least produced a raster so was the first to be brought in from the cold.

With a healthy hiss in the loudspeaker and a snowy raster on the screen this one looked like a goer, although trying to tune in a station produced nothing. The 12V supply was present at the varicap tuner but the range of the tuning voltage seemed restricted. The 33V supply to the tuning potentiometer seemed low and sure enough the decoupling capacitor (electrolytic type) proved to be leaky. Replacing it got the voltage swing back to normal but there was still no reception. The tuner itself in these early examples of the series (this one is dated 1978) is very small and uses two Germanium PNP transistors. There isn’t an obvious replacement that I could think of, Japanese types would fit into the space but tend to be NPN, meaning that the AGC circuit would have to be modified. A Grundig tuner would probably work, but is far too big to cram into the cabinet. The only thing to do therefore was to fix the original tuner. Shorting the output reduced the amount of snow on the screen considerably, suggesting that at least part of the tuner was working. Never the less, I decided to replace both the transistors. They were both marked ГT346A, which you can’t get here in a decadent West. Looking at what I keep for other sets, the AF239 (used in the B&O Beovision 600 and I believe some of the BRC mechanical tuners) looked hopeful, so with a bit of a fiddle and a struggle both were replaced. This made absolutely no difference, so time to think again.

There isn’t much else that can go wrong in these tuners, there was clearly no shortage of solder behind the Iron Curtain and all the joints looked perfect. The varicaps checked out OK too, with each receiving a roughly equal amount of bias. The mixer diode though measured open circuit, which is something I’ve never encountered before. This had me stumped, where does one get such a thing? Trying a few alternatives from a Sony tuner and a Mullard U321 type failed to improve matters, so the set was put on one side. As luck would have it though, a comrade then dropped in with another broken Vega, this time a 542 which is one of the last ones (plastic cabinet, silicon transistors in the line and frame circuits, focus control in a more sensible place where it doesn’t bite you so often). This was quickly swapped for a pair of Levi jeans and a couple of Beatles records, so I was back in business. This set has a later type of UHF tuner and IF preamplifier (fitted on place of the VHF tuner which UK sets don’t have) which are PCB mounted on plug in bases so a complete swap wasn’t really practical. However, the mixer diode looked similar so after a bit more fiddly work I had it swapped over. Instant success, so the AF239s would be a good substitute if the original transistors fail in one of these tuners. However, the appearance of a picture only went to show how bad the frame linearity was.

Bottom cramping was the basic problem, although the lock was solid. This tends to imply a lack of power in the output stage rather than anything wrong with the oscillator so I started there. Checks on the transistors proved inconclusive; Soviet transistors of this era seem to read duff even when there is nothing wrong with them so it was hard to tell what was going on. Checks on the key electrolytics drew a blank too. What now, send it to the salt mines?

Thinking back to when these sets were a lot younger (but equally troublesome from memory), some odd frame troubles were caused by a large capacitor which seemed to be somewhat over rated for what it does. I couldn’t remember the exact details, but in a plastic clip in the centre of the panel were two which answered this description. I took 1.0 MK +/-10% 160B to be 1uF, 160V, close tolerance type. Both read about 2uF, which is miles out, so once again the products of Capitalism had to be employed. These are much smaller and only rated at 100V, although measuring the voltages involved the 160V rating of the originals isn’t necessary. I suspect that it was the accuracy that they were going for.

With this done, the height shot up and the picture now looked quite good. These sets have an excellent focusing system where the control actually does something so soon the display was pin sharp. The correct setting for the HT supply is 10.5V; there is a ballast lamp in the regulator circuit which should glow only dimly if everything is working properly. With careful tuning, these sets should easily resolve the finest frequency grating on the test card (see pictures). The receiver section is very sensitive; it has to work properly in the Urals as well as in the home counties of course. One aspect which is a bit lacking is colour subcarrier rejection, there doesn’t really seem to be any! This could be because the SECAM system used in the USSR doesn’t have a fixed frequency subcarrier like PAL does. One way to get a good picture if using a Freeview receiver or a DVD player as a source is to switch the output to S-Video, then you get a pure monochrome signal to put into the modulator.

This has emboldened me to get on with the VL100. In an earlier session I had discovered that the reason that the line output stage wasn’t working wasn’t the usual dead LOPT but that the line driver transformer had an open circuit secondary winding. This in turn proved to be because the lead out wire had never been soldered to its peg, but even with this fixed there were still problems. Careful AGC setting-up got a picture but the IF strip was clearly still unstable as the gain drops to almost nothing when the metal cabinet shell is fitted. Also, decent pictures could only be obtained with a particular 10uF capacitor fitted in one of the AGC decoupling positions. Fitting a new one kills the gain, and now that I’ve messed about with it the original one gives poor results too. Soon after that, the line scan collapsed and the picture went off… A quick look showed that the driver transformer primary winding was now open circuit, and not in a repairable way either. Fitting the transformer from the Vega 542 (which looks much the same) makes the line stage run again and a few of the voltages then come up, but the HT rail then falls to around 7.5V. This suggests that the LOPT has given up too, which is highly annoying. The one used in the Vega is similar, so a transplant (with a few mods) is probably the next step. The outer (clear) bit of the tuning knob is missing too, does anyone have a spare one?

[Heatercathodeshort]

What an excellent write up! Well done, very much a labour of love.

There are probably thousands of these back in the USSR that need repair with no one to repair them so if you vanish from the Forum and your abandoned suitcase is discovered under the clock at Waterloo Station, we will know where to look. Regards, John.

[mark pirate]

Many years ago I was given a dozen or so of these little Rigonda sets, all with different faults.
Most were the earlier design with the deep (mostly orange) metal cabinet and side mounted controls.
I remember how strange they seemed to the usual Japanese sets, I had a lot of trouble with wires breaking away from the hinged PCB's

I did manage to get 3 or four working quite well and sold them on, I still have a couple of the bolt on 12v PSU's in the workshop.

Mark

[Welsh Anorak]

I've still got the manual (such as it is) for these little comrades. As you say, tests on the transistors told you nothing - obviously they are well able to deal with soft Western interrogation. I've replaced quite a few LOPTS in the past and I seem to remember a few odd sound faults. Also the Russian capacitors used to behave like our beloved Lorlin black beauties - the value, like share prices, can go up as well as down! Trouble is they always look so important and businesslike and therefore innocent.
Good luck with the other one!
Glyn

[Colourstar]

Brilliant! Really entertaining write-up Tim. What a stunningly sharp picture the set gives. Come to think of it I don't think I've ever seen one working.

I hope one day to acquire the large screen (20") hybrid b&w Rigonda allegedly owned by a friend of mine and buried somewhere deep within his workshop. I can't even find a picture of such a model on the net. Apparently it has a typical Rigonda hi-gloss wooden cabinet, although the interior is full of rough-sawn edges, so splinters are a hazard of servicing.

Out of interest, how were Rigonda marketed over here? Were they mostly through catalogues etc or did high street dealers have anything to do with them?

Steve

[Andrew2]

Whoo, I've had plenty of those on my bench in the past! As you say, they can produce remarkably nice picures when they are working correctly, trouble is that's not often! Weren't they on offer from the makers of Cornflakes for a while, or did I dream that?

[AD360 Rob]

I remember them being available in Woolworths, at least that's where mine came from. It went faulty, I gave it to a "telly man" to repair and never saw it again. (I was a lot younger and not at all experienced back then)

[Graham G3ZVT]

My grandfather had one of the earlier red ones, I repaired it once for him, I think the sound kept fading out and dressing some leads away from the loptx was all it needed.

The tuner was very sensitive I recall.

He also had a "Russian" (actually Latvian) VEF "Convair" transistor radio. I rather liked that set.

[jay_oldstuff]

Very nice write up, I enjoyed reading that. I've a small stash of these little sets in my cellar that I've picked up over the years from various places, sadly most of the ones I have have failed lopts in them. I've always wondered if the lopt from one of those cheep chinease 5" b&w sets that where everywhere just before analogue went off could be persuaded to work as a substitute.

[thermionic]

Hi. I got my little VL100, working here, http://www.vintage-radio.net/forum/s...ad.php?t=28857, which had a duff line output transformer. Excellent write up and picture on yours, Studio 263.

Jay, it might be worth contacting Howard, to see if his contact can still supply the LOPTy's for these sets.....

SimonT.

[Nickthedentist]

Wonderful, Tim.

I've never seen the metal-cased ones in the flesh so thanks for the picture too.

N.

[dazzlevision]

Originally Posted by Colourstar

Out of interest, how were Rigonda marketed over here? Were they mostly through catalogues etc or did high street dealers have anything to do with them?

IIRC, the national (and long established) wholesalers "Brown Brothers Ltd" distributed them to the smaller TV and radio dealerships.

[G6Tanuki]

I remember having a blue plastic-cased one of those back in the early-1980s; I used to take it up on the Chilterns with a 2-element BI antenna in order to do some TV-DXing.

It came to grief when I dropped it and the neck of the tube snapped off. Spares were unavailable from any of the usual outlets and buying Roubles on the black-market wasn't easy, so it got scrapped.

[Maarten]

Is the LOPT potted? If not, maybe it could be rewound?

[slidertogrid]

This thread brings back memories of a mis-spent youth...Woolworths sold loads of the early red Regonda model along with the larger Starlet.
I had a Saturday job with one of the local TV shops that did all of Woolworths repairs. The lopt was a common fault. A small potted thing if I remember correctly? The line output transistor was another common failure. Some parts were available. For those that weren't or took ages to arrive we got by robbing the odd set that came in with a broken tube, they were very useful and got robbed to the bare bones.
The only circuit was a really bad photocopy that was similar to the circuits used.
Woolies sold lots of horrors. Wye portables...components were packed onto the panel like an early Japanese transistor radio. they always gave a very grey picture any attempt at contrast resulted in a soot and whitewash picture with inter carrier buzz.
I don't even want to think about the Iskra portables, turn the brightness up and the set drifted off tune.. I can't remember the 'Modge' we devised to cure that..
I too bought a job lot of faulty Vega plastic sets, I remember going to a lock up that was full of faulty returns. allegedly something to do with Freemans mail order. They usually destroyed faulty electrical stuff back then so these may have been liberated on the way to the clay pit!

Rich.

[julie_m]

I used to have a "Rigonda M" sometime in the '80s. Mono, with a screen about 15cm. and a very long telescopic aerial that fit in the carrying handle when collapsed. It ran from 12V and had a mains PSU that clipped on the back. I remember I swapped it with a friend for something, but not what for. I think he lent it to his older sister and she broke it .....

[Sideband]

Originally Posted by dazzlevision

IIRC, the national (and long established) wholesalers "Brown Brothers Ltd" distributed them to the smaller TV and radio dealerships.

It was most definitely Brown Brothers. Back in 1970 when working at a small family-run business as my first job, they used to stock Rigonda products including these little sets. Brown Brothers were local to us in Croydon and we used to go there for the spares as well.

[Studio263]

Here are some pictures of the VL100, which is currently as dead as Laika but I'm hoping to get it going again soon.

The later 'Rigonda M' is often mistaken for a VL100 but externally the two sets have many differences. A sharp eyed agent will spot them all straight away I'm sure, but some of the key ones are:

No bright trim around the tube surround or behind the control knobs

The tube surround is a different shape and doesn't have the "peak" on the top (which always seems to be broken).

The knobs are different, with their functions written on the centre caps.

The badge is at the side and says 'Rigonda VL100', the badge for the Rigonda M is on the front just under the screen. The 'Transistor TV Set' script is also absent from the VL100.

The chassis is similar, however as I've never seen two Rigondas that were exactly the same its hard to say what the key changes were. The R+TV S entry is for the VL100, which is why I suspect most people use this model name for the Rigonda M as well. Simon's post above shows a Rigonda M if you want to see the differences.

This particular one is remarkably original and complete, aside from the tuning knob. It is still in its packaging and retains its square "loop" aerial, DC battery cable, Bellingski Leeov antenna adaptor with switchable 10:1 attenuator and a little cotton bag full of strange stuff (Polonium?) which presumably kept everything nice and dry. The inspection card suggests that it was made in May 1972, which the internal date stamps agree with. Does anyone have an earlier one?

[Studio263]

Inspection card picture here.

[Studio263]

Dear Comrades,

Mikey's TV junk swapmeet yielded a few more Rigondas, strangely no-one else wanted them... They have been on one side since then whilst some less interesting tasks have been cleared.

The most hopeful was another Vega 402, very similar to the last one. Hiss on sound but little else was the starting point, with no EHT (and therefore no tuning voltage). A meter check showed that the LOPT was open circuit on one pin, so a known good one was fitted. This made no difference.

The HT was low at just under 7V, this was due to nothing more than a dead spot on the 'set HT' control. 10.5V is right for these and it adjusted to that nicely. A big 16KHz waveform was present at the base of the line output transistor and 11.6V was there on the relevant pin of the LOPT but there was no spark at the end of the overwind, with nothing getting hot. Open circuit line output transistor? Almost, the lead out wire between the transistor tag and the PCB had come away, leaving a tiny gap. Touching it with a screwdriver brought up a line whistle and a burst of EHT. A quick dab with the iron solved that.

The resulting display was clearly out of focus, running at a slow frame rate and unstable. There was still no tuning either, just a hiss. The frame problem was due to the same capacitors as last time, as was the tuning voltage issue (see the previous thread). The focus problem was due to the focus control (1M) changing value to well over 10M. There was a definite step in the resistance change as the control was turned, suggesting that arcing had burned a hole in the track. Since the remaining part still measured over 1.5M I decided to paint over the damaged section with silver loaded paint; the component is an odd size and western alternatives do not settle well there.

This left the instability, which took the form of horizontal lines, line pulling, gain changes and the like. A look around the likely electrolytics in the IF and AGC circuits rooted out a few defectors but stern action (replacement with junk box alternatives) failed to provide a cure. A look on the timebase panel uncovered a 20uF / 100V capacitor which was completely open circuit, but replacing that made no difference either.

The tuner was now suspect, as it was last time. Dealing with this is no fun however, so I decided to try and prove it first. My Philips PM5509 pattern generator tunes down to 50MHz so that signals can be injected at IF, so this was connected to input of the IF strip. The result was a perfectly stable display with all the frequency gratings perfectly displayed, indicating good alignment. Altering the attenuator on the PM5509 showed that the AGC was working too, so the tuner was clearly the source of the trouble.

These sets were originally designed for UHF / VHF operation but for the UK the insides of the VHF tuner had been removed. To make up for the lost gain (the UHF signal passes through there normally) a single transistor stage is left, many Japanese sets are like this too. Moving the injection point to the tuner output (e.g. up stream of the transistor IF preamplifier) gave a noisy, unstable picture, suggesting that the fault was in the preamp box rather than the tuner.

The transistor was the expected small metal can type (BC108 shape) but with four legs and Russian writing on the side. The ones taken out of the tuner of the other Vega 402 (see the other thread) were still cluttering up the workbench and looked similar, despite having a number a few digits different. Never mind, in one went. Up shot the gain, with no more instability in sight! Connecting the tuner back up restored the excellent picture these sets are famous for.

If all this sounds a bit to easy, removing the IF preamplifier has been made extraordinarily difficult. There are three screws, on visible, one hidden behind the tuning potentiometers and one hidden behind the front panel. To reach the second two the front has to come off, which means the tube has to come out. Tiny wires, all much the same colour, attached to the flimsy tags of the tiny scan coils, have to come off. As does the tube base, revealing pins with the diameter and the structural integrity of an ant's eyelash. Not fun, but it was done.

The set is now a diligent worker and a credit to the state. One remaining issue is that the picture is slightly crooked. Easy - just twist the scan coils around right? Yes, but they are stuck fast to the tube. With that tiny neck I'm loathed to pull, twist and heat too much - it may be easier just to fit another tube for now.

LOPTs remain a common issue with these, but I've started chipping the resin off a failed one in view of doing a rewind. They are small, and EHT multiplication means that the overwind probably doesn't have too many turns on it. I'll post again once I know if repairing these is possible.