1960s Kolster Brandes Prima Ballerina KG026 radiogram

[dougietamson]

Hi all, 1st time poster here.

I've just collected what looks like quite a high spec radiogram, stereo FM tuner, 2x10watt into 4 speakers and made in West Germany.

The seller claimed it powers on ok and the radio works tho there is something wrong with the record deck.

I've not powered it after the drive back.
Capacitors all seem ok, it's a PCB design, all components are of the more 'modern' type.
It came with a spare valve, ECLL800, in a box sent by the service company, CRTS Ltd, Sidcup but I suspect that the old one was put in the box.

I powered the tape machine up, the tape played back ok but the volume control seems to be stuck on full volume and the mains on/off is stuck at 'on'.

I can't find any schematics.

Here is some scans of the operators guide.

Doug

[dougietamson]

After a bit more digging on-line, I found the service manual

http://www.kbmuseum.org.uk/kb_servic...B_KG026_kb.pdf

thanks goes to the kb museum site

Doug.

[G6Tanuki]

Aiee! The ECLL800 was a valve I learned to hate. Two power-valves and a unity-gain triode (for use as a phase-inverter to drive one half of the power-side) crammed into the one seriously-hot-running B9A bottle.

I came across them in the 70s in some water-board Telefunken VHF mobile-radios where they were used as the TX modulator. The stock response to "distorted audio on transmit" was "Have you replaced the ECLL800?" which was fine so long as they were still available at a sane price.

[Nuvistor]

Only came across the ECLL800 in a Grundig stereo radiogram, both valves were faulty. I wanted to check bias arrangements to confirm they were not overdriven but the RG owner said no it will be ok. He was an ex service man and had brought the RG home from Germany. He said they needed changing every couple of years and it would be ok.

It was, I expected a call back within a couple of months but it didn’t occur and the guy came into the shop for other items. They were expensive valves and that concerned me but again he expected it.

[paulsherwin]

I've only seen them in German stereograms. I wonder if this model was actually made by Nordmende, Blaupunkt or whoever under contract, either just the chassis or the complete stereogram. The circuit diagram in the service info has a distinctly German look to it and contains some German text.

[crackle]

I didn't think this radiogram had a stereo FM tuner, but looking at the schematic it appears there is an option for a stereo demodulator. Is your radiogram fitted with the stereo adaptor?
The volume control looks unique, as well as the normal 3 connections it appears to have 3 additional taps on the track.
It is interesting to hear it was made in Germany.

Mike

[dazzlevision]

This set came from K-B’s German sister company, Standard Elektrik Lorenz.
The service sheet shows the SEL logo on the copper tracks layout.

[paulsherwin]

You know much more about KB stuff than I do Mike! I was just speculating and may well be wrong. The circuit doesn't look very Footscray though. When did ITT take control of KB and Schaub-Lorenz? Maybe it's a rebadged Schaub-Lorenz model.

Post crossed with Dazzlevision.

[dazzlevision]

https://de.m.wikipedia.org/wiki/Stan...lektrik_Lorenz

[crackle]

At this time a lot of KB branded radios etc, were fitted with STC chassis, this one seems to be different though.
Agreed the SEL logo can be seen on the images of the printed circuit boards.

It seems in the 60's KB goods were starting to be manufactured in different countries around the world probably as a result of ITT's massive domination of the consumer electronics industry.
I have KB radios made in Japan and S. Rhodesia, but it was not until the early 70's with the advent of ITT-KB branding that the world wide manufacturing really seems to have taken off, countries like Austria, Germany, Hong Kong, Japan, Malaysia, Malta, Taiwan, all contributed to to the manufacture of ITT consumer goods.

Mike

[dazzlevision]

I think this SEL made radiogram was probably the "top of the range" in KB's offerings at the time and saved KB in the UK from designing their own electronics, which might only sell in limited numbers and therefore be uneconomic to so do. It should also be borne in mind that UK consumers were a lot more driven by (lowest) price than their mainland Europe counterparts.

Of course, with the rising costs of labour in the UK and Western Europe, manufacturers turned to (initially) the Far East for their lower end products. This was equally true of UK based firms such as Thorn and multinationals such as ITT.

[vidjoman]

I thought the layout/circuit diagrams looked familiar and so I dug out a drawing I have of an RGD model RG225 Belcanto radiogram. Circuit is 'almost' identical and layout very similar. There is no SEL logo shown on the PCB's.
I noticed on the PDF above, the number at the bottom of page 2 is 920.137a - my drawing is numbered 920.135a and dated 8.64 so it looks to be from the same stable. The RGD has more comprehensive tone controls. It also has the ability to add a stereo radio module that is identical. It has a socket onboard to add a reverb unit as well, but don't know if that was supplied as standard or a optional extra. the Power supply is almost the same.

[dougietamson]

Powered it up today no smoke...yet

The mains wiring looked a bit dodgy, it has a old style 3 core mains lead red, black and green.
At the plug end only the red and black are connected, the green has been cut and taped up with some old sellotape. At the other end of the mains lead the green is connected to the chassis. The red and black are connected to an internal 3 pin (rectangular) socket which is used for the tape deck, attached to the red and black is white dual core cable which connects to an internal European style 2 pin (round) socket, this is where the chassis gets it power via a European 2 pin plug. See pics.
The UK plug had a 13amp fuse which I swapped out for a 3amp one. I removed the sellotape and replaced it with electrical insulating tape, still not connected to the earth pin yet tho.

I connected it up as it came including the 4 speakers but covered up the bare mains wires with tape, it powered up ok and managed to tune radio stations on FM, MW and LW.

Next I tried the ECLL800 from the box that a spare was delivered in, it worked for about 10 mins then came the distortion so looks like it was the one swapped out but not marked as faulty.
The replacement valve is a newer one as it is marked SEL Lorenz, the other 2 are marked only Lorenz. See pics.

I found a supplier of tested used valves for 28euros each.
One of the ECC83 is a Mullard with date code from 1965 and the other ECC83 is a Lorenz.

I'm not sure if it is fitted with thw FM stereo unit, I tuned into a local strong FM station, the magic eye goes to one solid white bar, I pressed the stereo trans button but it doesn't latch and the radio goes very quiet.

[paulsherwin]

Don't buy new valves without a specific reason to do so. The existing ones are unlikely to be bad.

Be very careful with this, as it sounds as if somebody has been bodging. Use a plug in RCD adapter if you don't have RCD on your consumer unit.

[crackle]

Is an RCD adaptor going to be any use if there is no earth connected?

Mike

[dougietamson]

I have a 30mA RCD plug adapter between the radiogram and the mains socket.

I've taken the UK to German wiring/sockets/plugs mess out of the equation and powered it up from the factory fitted German/EU plug fitted to the chassis, I have plenty UK/EU adapters from living in France for 10 years.

The radio sounds good, plenty of volume and plenty of bass, I connected an iPhone mini jack to the 5 pin DIN pick up and tape recorder socket, tape input is selected when you press the gram and LW keys together.
The volume level for the line inputs is a bit lower than when the radio is selected. I'll investigate the tape input/output when I fix the Grundig TK24 tape recorder that came with it.
There are 2 speakers for each channel, a 6.5"x10" woofer and a 5"x7" mid range, crossover and switched DIN socket for an external speaker.
The 5x7 is branded with the SEL logo and 3 watt 4.5 ohms, DC resistance measured at 3.9 ohms.
The 10" speaker has no markings.
The crossover capacitor is 100uF and the coil has no marking, pic attached.

Doug

[paulsherwin]

Originally Posted by crackle

Is an RCD adaptor going to be any use if there is no earth connected?

Yes. They work by sensing any difference in current between the live and neutral connections. If there's more current on live than neutral then it must be leaking to earth somewhere (possibly via your body).

An RCD won't stop you getting a belt, but it should prevent a fatal shock.

[crackle]

Many thanks to Doug for the scans of the user instructions, they are now in the KB Museum.
http://www.kbmuseum.org.uk/user_inst...KG026_inst.pdf
Mike