Reviving Radio in old German Radiogram
 

Evening all,

I have recently acquired a German radiogram, from the early 60's, or late 50's, (possibly a Weimar?) and would like to get the radio in working order. It does in fact work, I tested it briefly on a MW station and it sounded okay, however I am aware that it is unwise to simply use without taking necessary precautions.

I plan on replacing all of the old capacitors in it, apart from this is there anything else that I should be doing?

Any advice would be much appreciated.

Regards,

Michael

Re: Reviving Radio in old German Radiogram
 

Hi Michael and welcome. You will get plenty of help and advice but it's best to indicate your existing knowledge level-we can't tell. There may be one or two items that could create a cascade of damage if they fail [commonly known as "that capacitor"] but wholesale replacement is discouraged here as it's likely to lead to total confusion. One at a time and test is the mantra:D. The "change all caps on sight" notion has an unknown origin but seems to have migrated from Audio Forums or You Tube in recent years??? Many new members seem to assume it's the first thing to do but not so at all!

Dave

Re: Reviving Radio in old German Radiogram
 

The radio/amp chassis looks like a Stern Radio job, very similar to the one used in this radio:

https://www.radiomuseum.org/r/stern_...4680d4680.html

This might do as a basis for a schematic ?:

https://nvhrbiblio.nl/schema/RFT_4680A.pdf

Lawrence.

Re: Reviving Radio in old German Radiogram
 

It looks like a Telefunken to me. I don't think I would just blanket change all of the caps. I think I would be inclined to run it for a few hours monitoring it an checking the main smoothing capacitors are not getting warm. The only capacitors I would consider changing would be the mains input filter cap if fitted (replace with a suitable X type) and perhaps the anode to grid coupling caps.

(Reply crossed with Lawrence)

Re: Reviving Radio in old German Radiogram
 

It looks very like this

https://www.worthpoint.com/worthoped...950s-219366601

Re: Reviving Radio in old German Radiogram
 

The last picture in post #1 appears to show that a tweeter(?) has been chopped out - although the schematic only shows one speaker.

Re: Reviving Radio in old German Radiogram
 

Hi All,

Thank you for replying.

With regards to my knowledge level and experience, I don't have a high level of knowledge, especially when it comes to old radios. Having said this I do have a basic understanding of electronics, and I am fairly good with a soldering iron.

Lawrence, It does look very similar to the radio in the link put up, and the schematic is definitely better than nothing, so thank you very much.

It does look like there was a tweeter or smaller speaker at one time, does anyone know how I might go about fitting a replacement? The schematics of the similar radio only show one speaker, although possibly this is due to there being less room available than in a radiogram?

I think I will see about running for a while and monitoring it like Martin suggested.

Re: Reviving Radio in old German Radiogram
 

It does look very like Martin's Telefunken. It appears to use a printed circuit board and an EM84 tuning indicator, which would date it to the early-mid 60s. If it's that late then it probably doesn't contain any wax capacitors so there is no reason to change them all - they'll probably be fine.

It's just possible that it's an East German copy of the Telefunken. The valve manufacturers will reveal this - if several of them are Telefunkens then it's a Telefunken, but if they are all Eastern European brands then it's a copy.

It looks as if the tweeter was connected via a simple capacitor to chop off the bass rather than a full crossover. A certain amount of butchery has taken place judging by the choc block connector - possibly the original tweeter failed and the owner intended to replace it, but never finished the job. It should be easy enough to replace, but you should sort out any other issues first.

Re: Reviving Radio in old German Radiogram
 

I ran the Radio for about two hours yesterday, and it appears to be in good working order. The UKW (VHF) is much much clearer than the SM MW and LW, but I imagine this is down to poor signal? One thing I did notice is that while playing audio, the radio would make a digital sounding signal note in the background for about 10 seconds or so, and this happens roughly every three and a half minutes. Does anyone know what this could be?

Re: Reviving Radio in old German Radiogram
 

Hello there,

The digital sounding signal you refer to could well be a mobile phone close to the radiogram, most mobiles poll the network every so often.

Re: Reviving Radio in old German Radiogram
 

Yes very likely. My Hacker portable picks up my mobile if it's close enough. Oddly enough, the Leak valve tuner doesn't seem to be affected.

Re: Reviving Radio in old German Radiogram
 

Mobile phone signals are similar to pulses of broadband noise, and can break through into almost any amplifier. The handset transmits periodically to check it can still see a cell tower; and also transmits back to the tower to acknowledge a call or text message about to come in, so a phone placed near a radio will usually create a burst of noise in the radio just before it rings (or beeps for a text message).

You used to be able to get various gadgets that would respond to these bursts, as a sort of "extension bell" for mobiles. (A former work colleague of mine had a 10cm. blue plastic Tardis with flashing LED and "materialisation" sound effects, which went off just before his phone rang.)

Due to the nature of the signal and the power level involved, the interference has only a few tens of centimetres of range.

Fixing German Radiogram BSR Record Player
 

Hello all,

I have recently acquired a 60s German Radiogram, fitted with a BSR UA14 (I think) which I believe to be made by Stern Radio, as the radio is very similar to the Stern Radio Weimar 4680A. I have not yet done anything to it, except from removing old grease from, and re lubricating the turntable, although radio on it seems to be working perfectly. The record player now seems to be mechanically fine, the record drops, the platter spins, and the arm moves across and lowers onto the record, but no sound comes out of the speakers at all, not even static or crackling. I'm not sure if I'm doing something wrong, or if it is a fault with the radiogram. The button I am pressing on it which I presume switches to the record player input is marked 'AUS'. I think this as it is the only button that doesn't switch between MW/LW/SW/VHF, but I am not too familiar with German abbreviations, so it could mean anything. When I look at the back of radiogram when this button has been pressed, the valves stop glowing and it is as if the power has been switched off.

I am new to Radios and record players, so any advice at all is welcomed and much appreciated.

Regards,

Michael

Re: Reviving Radio in old German Radiogram
 

Aus means “out” or “to exit” so could well be the “off” switch, especially if the valves lose power ! Cannot see the controls but sometimes you press two buttons at once to select the record player. Is there a symbol for “pick up”, rather like Q but the tail usually goes to the left ?

Re: Reviving Radio in old German Radiogram
 

Hi,

AUS is indeed the Off Button.

Although not familiar with this model, in order to activate the gram input it was common practice to simultaneously press two buttons.

Although your last photo is rather out of focus, it would appear that you press the 2nd and 3rd button from the left to switch to gram.

Hope this helps.

Re: Reviving Radio in old German Radiogram
 

Fantastic! Thank you all very much indeed, it does appear to be two buttons that switches it to the record player. Only catch to this is that there is no sound picked played, only a high pitched screeching noise when the set is on full volume, and on certain tone control settings. Any ideas?

Thanks again for help around buttons.

Michael

Re: Reviving Radio in old German Radiogram
 

Daft question but is there a cartridge fitted to the arm as I cannot see one ? If there is a cartridge, does it have a stylus ? The knob for a turnover stylus looks like it should poke out from the end of the arm, but is missing. Could be that a replacement cartridge has been fitted in the past.

Re: Reviving Radio in old German Radiogram
 

Yes there is a cartridge fitted, however there wasn't when I took the photo. I originally thought that original cartridge was missing, however I found it in the bottom of the radiogram covered in cobwebs and very manky indeed. It was a BSR TC8H. I thought it too manky to put back on, so fitted another mono cartridge that had been a spare from an old record player. The high pitched noise happens as soon as the input is switched to the record player, and the volume is on full.

Re: Reviving Radio in old German Radiogram
 

Do you know that the fitted cartridge works (in another player for example) ? The high pitched noise sounds like feedback (it is only on full volume so maximum gain from input to output). The feedback and lack of signal could well be because the input is effectively open circuit due to defective cartridge or wiring or switching, or poor screening/earthing, or proximity of input/output cables. Check all of these as a first move. You could also try a capacitor in place of the cartridge (say 1000pF) to help narrow it down.

Re: Reviving Radio in old German Radiogram
 

Could easily be a defective cartridge, don't know it to be working or not. Will have a look at these. thank you.