Siemens Radio for Restoration

[Geaney]

That's a kind-sized flywheel John!

I've got a couple of German piano key radios to sort one day. It's all that piano key switchery that give me the heeby geebies.

Also, I don't find German circuits very easy to follow, due to unfamiliarity I suppose.

They do appeal to me greatly, in a way that few post-war British radios do. If/when I get round to the two that I have, I'll probably get a local firm to spray the cabinets with catalytic lacquer, as near as original as can be had. You can buy pre-cat cellulose lacquer here in aerosols, but I don't think that DIY spraying - certainly not by me - comes close to commercial standards. Same with cars - to bead blast an alloy wheel and powder coat it to any colour is £40. Wouldn't cost much less than that to use aerosol sprays to get nothing like the standard of finish. A man's got to know his limitations!

Hi David, on this Siemens set the switchery is fully exposed and easy to get at - about the only part of the set that is!

The lacquer on the cab is badly cracked all over so it will need the full works at some stage. At the moment I'll concentrate on getting it back to life then I'll look at all the cosmetic stuff. I find German radios to be like (modern) German cars (drove BMW's for many years) - they focus on some aspects of the product and they are engineered to perfection, other parts are then really badly done. The cab on this radio is particularly weak - the wood quality is very poor. Still, I can mess with all of that later on!

Re cars, I had a number of 5 series and the engines and transmission were always perfect but the electrics continually broke down! I gave up on them after the ignition lock seized on one - it had to be towed back to the dealer (from an underground carpark!) and the rigmarole I had to go through to get a new lock and key would warrant a whole separate thread!

Cheers, John

[Geaney]

OK, that's definitely the nastiest re-cap I've done so far. Getting access to the caps was a nightmare for most of them. I've probably dislodged some wires along the way - hopefully not. I measured each cap as I went and 100% failed - were between 50% and 450% of marked value! At least changing them all was justified. I found one small electrolytic that measured exactly the right value so I left that one for now.

In contrast, when I checked the resistors just about all of them are within 10% of the stated value - or better.

One step closer to first power up........

Cheers, John

[Mark R]

Looking good John.

cheers Mark

[Andrewausfa]

That looked as if it was fun John. I changed all the capacitors in my Grundig 2035 as the first few I tested were all duff.

Andrew

[Geaney]

I decided to try a first power up. I fitted all the original valve even though I know the audio output ones are shot. I hooked it up to the variac and brought the volts up slowly. No bangs or smoke so off to good start. Once the valves had heated up I got good FM reception but the audio is very distorted at all volume levels - looks like I'll have to wait for the replacement ECL82's to arrive. I didn't leave it on for too long just in case.

Still, the set is looking good at this stage.

Cheers, John

[Tedzed1]

Well done John, looks like you are on a winner with this radio.

[Geaney]

Well the ECL82's arrived but fitting them made no difference - bummer. I hooked up an audio source to the tape input and it plays clear as a bell (should have done that earlier I suppose). So, my problems are before I get to the audio output stage.

I had a go at troubleshooting but there are many differences between the circuit diagram and the set itself so I guess I'll have to keep hunting for documentation that more accurately reflects the set I've got. So, major distortion on FM and I tried briefly on AM last night but wasn't getting anything except one very faint station so I suspect I've still got plenty to do at the front end of this thing.

At least the sound quality is excellent from the phono input so the speaker overhaul was worth the effort.

Cheers, John

[Geaney]

Deep joy! The Siemens set is now working nicely. I decided to enlarge the circuit diagram I had and make it as legible as possible so I spent the morning messing about with Photoshop. Then I started working through all the voltages shown on the diagram - starting at the audio end and working back. I found there was no DC to the plate of the EABC80 - it turned out to be an open circuit 220K resistor.

I haven't checked it out on AM yet but I'm sure it will be fine. Now I can get on with all the cosmetic stuff bit on the chassis and the cab. I love that moment when the set suddenly works after so many years being idle.

Cheers, John

[Geaney]

Thanks Guys,

I think I found it over on radiomuseum.org

http://www.radiomuseum.org/r/siemens_mei...tereo.html

It's funny, I spent ages looking through all the Siemens models on radiomuseum to no avail. When I did a Google search on 'Siemens Stereo Radio' one of the first results was the one above - so much for the search feature on radiomuseum.

I'll get cracking on finding out what exactly they meant by 'stereo' once I get hold of some documentation.

Cheers, John

Well my set is not a standard RD10 so it looks like I've another odd one here. The cab on the RD10 is square and mine is rounded. My set does not have shortwave, just long and medium plus FM. Having looked at all the various Meistersuper models online the chassis in mine most closely matches the RD10 (minus the SW band and associated circuitry and switches, etc). Once I get the cab fixed up I'll ask on radiomuseum.org if anyone knows exactly which model I've got.
Cheers, John

[Tedzed1]

For some reason, John is having problems uploading pictures to the forum, so here is the latest picture of the siemens radio.