Rigonda Stereo - Reviving the beast
 

Well, finally got around to taking the back off this set and having a look around. Which is a LOT easier once you realise that the voltage selector has to come out first.

First expression was a happy one as everything was present, and seems to be intact. Even down to two little period looking plastic packets attached to the back panel containing spare panel lamps and fuses! Second one was also a good one as I spotted a magic eye tuning indicator (didn't realise that was there before as I haven't cleaned the front panel yet), immideately followed by an irritaited grumble as I spotted that half the valves have all their text in Cyrillic. I may need a hand with some of the translations!

This set is a long way from the last one I worked on, my humble Defiant MSH 452. Not a wax cap in sight, PCB based, and generally looking like a far more serious bit of kit.

My first instinctive reaction upon getting a set would be to start replacing all the waxies before even touching anything else...but as there aren't any in this set, where do I start? Obviously the smoothing electrolytics are likely to be scrap, but beyond that?

Obviously given that the whole thing's a grubby mess, the switches and such will all need a thourgh clean, and the deck's an unknown quantity at this point in time. Being honest though, in my opinion the radio's the important bit here. This is a set I intend to use, and that's what it'll be doing most of the time.

Fingers crossed I won't need to refer straight to a schematic for this one, as I reckon it'd be a bit of a scary diagram!

PS. The one clean shiny valve in the image below shouldn't be treated with suspicion, I've already had that out and given it a wipe down so I could read the markings...

Re: Rigonda Stereo - Reviving the beast
 

Hi,
You might find this thread useful :)

Good luck. I've still not got around to resurrecting my Rigonda Bolshoi. I might make it a winter project. Yours looks comparatively simple inside... 8-)

Cheers, Kat

Re: Rigonda Stereo - Reviving the beast
 

It should take 240v, (Oh okay 230v!) but I'd check. Rigonda stuff was imported, so you should be OK.

You don't go straight for valves, but just so you know, most if not all domesttic Russian Valves have direct UK Equivalents. The heaters are 6.3 Volts, and I bet they are wired in series.

The one thing they don't seem to use is an EABC80. Most of them use a diode here, or other valves, like the Unitra Sets. You probably wont need a circuit. I bet it only needs 2 caps changing - If it's in Push Pull, there are 2 capacitors where there is usually one. Or, in this case, 2 channel output - Easier still, as you can compare voltages.

Russian Caps are good - so much so that I'd just plug it in. Keep my hand on the On/Off switch on the plug, and I'd be surprised if nothing happens.

The record deck would be cleaned up and used in the usual way. For styli, look at German Manufacturers. I once had a Rigonda Party Time Calipso in for repair, and I found a Tandberg Stylus that fitted perfectly.

It's very good kit! Seriously so.

Cheers,

Steve P

Re: Rigonda Stereo - Reviving the beast
 

Hmm, just been cleaning the valves up a bit (so that I can actually see what they are!), will look into what the equivialants are, just in that I'd like to see what the setup in here is.

At the present point in time two that I've not been able to find direct links to are labelled OTK 6 and 6H2P (the latter translated). If it works though I'm not going to worry about that for now!

Will find a plug and put it on the limiter after dinner, and see what happens. Need to track down some speakers too, and I don't want cooked output transformers to contend with.

Re: Rigonda Stereo - Reviving the beast
 

The 6H2P is equivalent to the EAA91. I have only found details of the Russian OTK 2 and OTK 4 valves so far, I'll see if I can find the OTK 6.

Howard :)

Re: Rigonda Stereo - Reviving the beast
 

Thanks Howard - just spotted that there's a valve layout diagram on the back, and the valve listed there appears to be equivialant to an ECH81, which is one that I've heard of. Reckon there may be more print on that one that I couldn't see as it was very faint.

Just unearthed a couple of speakers I forgot I had from behind the table in the kitchen, so might be ready for some experimentation soon.

Thanks for the heads up on the voltage, Steve. It's got settings for 110, 127, 220 and 240V, so I should be okay. No excuses for forgetting to set it either, as I have to take the selector out every time I take off or replace the back panel!

Re: Rigonda Stereo - Reviving the beast
 

And what do you know?

It's alive! So far I'm still running it on the limiter, and will do for a little while yet, as it's running brighter than I would maybe expect (though I imagine this set's a little more greedy than the old Defiant). Just keeping an eye out for the caps getting warm (so far they're stone cold after a few minutes - and yes I did switch if off before stuffing my hand in there). Only thing I had to do was replace two of the three panel lamps.

Have got reception on both medium wave and strong FM reception, just with the internal antenna, even on the limiter. Even the tuning indicator works. Which is really pretty too.

Anyone got any ideas how much power I should be expecting this set to be using?

Re: Rigonda Stereo - Reviving the beast
 

First, Well Done! I thought it would.

Run it for a while, and ensure nothing gets hot, then there are 2 capacitors you must change. Go on the Control Grids of the EL84's (At a guess) and check for any postive volts.

From here, you should trace back to a certain capacitor. On one side is a Strong DC Voltage. And these caps tend to go leaky - so change them.

Then reassemble, make sure the set still works (!) and then try it without the limiter.

Then it's cleaning, lubricating and fixing the deck.

Cheers,

Steve P

Re: Rigonda Stereo - Reviving the beast
 

Stupid question, but which pin on the EL84's is the control grid?

Thus far I've not managed to track down a schematic...and for some reason I can never remember which of the "g's" on the datasheet is the control grid! Sure I'll get there eventually, but right now, I'm playing it safe and asking.

Re: Rigonda Stereo - Reviving the beast
 

Control grid = g1

TimR

Re: Rigonda Stereo - Reviving the beast
 

No trouble mate. Rather you asked than blew the set up. Or yourself for that matter.

First, read this:

http://www.vintage-radio.com/repair-...ut-stages.html

I only said that I thought it was an EL84, but the pins are:

Pin 2 : The pin you want - Control Grid.
Pin 3 : Cathode and Suppressor Grid.
Pins 4 and 5 : Heater.
Pin 7 : Anode.
Pin 9 : Screen Grid.

Cheers,

Steve P

Re: Rigonda Stereo - Reviving the beast
 

Yep, answered my own question too, and happy I was right. Presently we've got 0.08V positive DC on pin 2 of the EL84's. And it's stayed at that point for at least ten minutes now.

Changing these caps is definitely going to wait until I've got the chassis out of the cabinet, as I can't even see which capacitor this is above the board (though I can clearly see one pin from the print side). There are a heck of a lot of capacitors there, and they're all green, and all the same shape! At least in the last set I did this capacitor did me the service of at least looking like the most distressed one in the set and making itself conspicuous. No such luck here.

Just investigated the deck a bit, and confirmed that it does turn under its own power, though slightly slowly (to be expected!), and that all of the controls work (including stop and the motor cutout), as does the pickup. Four stylii came with the set, though what shape they're in remains to be seen.

Re: Rigonda Stereo - Reviving the beast
 

Well, that has to be the easiest set to get the chassis out of ever. Two thumbscrews to undo then lift the deck out (having unplugged and labelled its plugs), then undo the four screws from underneath, then the whole lot, front-panel, buttons, knobs and all, just slides out the back. Clever them Russians. I LIKE designs like that.

Now with the chassis in the light of day (um...well, light of 50W halogen desk-lamp anyway...), I'm able to better have a look around.

Cleaning the dust of a few components around the EL84's revealed one resistor that's obviously been getting very hot and bothered at some point in the past (though it wasn't running hot yesterday to my knowledge).

What really baffles me, is that this resistor seems to run between pin 7 of the EL84/one of the output transformer primary connections to thin air...there's a terminal/test point there. Have to wonder if this terminal DOES exist for testing purposes only, or maybe has a use in another version of the set? Maybe the overheating's damage that was done long ago. Withuot a layout diagram, it's hard to say. It's also really hard to find the decoupling capacitor I'm after!

Reckon I've found the sucker (or suckers in the case of this set), as pin 2 seems to lead to somewhere in the region of the capacitor I've labelled. No other cap in the set has bulgy looking rubber ends...these two both do. Hmmmm....

Does 1500pf sound about right for the capacity of these?

PS: Steve, you were right, they ARE EL84's.

Re: Rigonda Stereo - Reviving the beast
 

Yes. Change them, and that Resistor too. That'll be all you need to do at a guess.

Then clean it and sort the deck.

Cheers,

Steve P

Re: Rigonda Stereo - Reviving the beast
 

Cheers for the quick response. How critical is the value of this capacitor? Closest I've got to hand is 1000pf/1kV, or going the other way, 2200pf (in fact, seem to have hundreds of them). 1500's pretty much bang in between the two! As for the resistor, it'll have to wait until tomorrow. I'm assuming of course that a 2W, 4.7K resistor isn't too complicated for Maplin to stock these days. *crosses fingers*

Re: Rigonda Stereo - Reviving the beast
 

Hi Zelandeth.

Seeing as you are playing about with Rigondas, have you seen this site?http://oldradio.onego.ru/

Might be worth seeing if your set is shown.


Rich.

Re: Rigonda Stereo - Reviving the beast
 

Simple answer...either although I would probably go for the higher value of 2200pF given the choice. I would also check to see if there is a filter capacitor across the mains. I've had these go off with a sound like a rifle shot in Rigondas in the past....the end cap of the last one whizzed past my ear ;D.


Rich.

Re: Rigonda Stereo - Reviving the beast
 

Well, got the replacement caps in without incident, will pop out to Maplin tomorrow see if I can get hold of a suitable resistor. If not I'll have to wait a few days for one to arrive from RS, which would be annoying.

Fingers crossed I can get hold of one...or discover that there's one rattling around in the parts drawer. That's an investigation for the morning though! Right now, sleep beckons.

Thanks for all the help so far.

Re: Rigonda Stereo - Reviving the beast
 

Zel
1500pf is unlikely to be a coupling capacitor - too small - I would have thought at least 10nf. Can you locate the previous stage and determine what its anode pin is?

Re: Rigonda Stereo - Reviving the beast
 

Will be tricky without a layout & schematic diagram, but I'll see what I can do.

Given the way the set's built on 3 main PCB's though, it looks like each of the boards on the right is an amplifier. In which case I'd be poking around for the anode of the 6H2P (ECC83? Can't be an EAA91, as it's not got enough pins). Which means I should be poking around pins 1 and 2. There does seem to be a trace running from pin 1 in the general direction of the EL84's, but it's nigh on impossible to follow.

There is a 0.01uf cap in this area though, which seems to be connected between a1 (pin 1) of the 6H2P and one of the speaker terminals (via another couple of caps).

Really wishing I had a circuit diagram right now!

...and to add to the fun, I've just noted that while the set's been getting worked on, that the AM tuning pointer's driver cord has jumped off its drive spindle. Fun fun fun...