Siemens Schatulle M 47 Tabletop w/ odd Markings

[myrgatroyd]

In Germany FM was initialized in ´49. There was an international meeting in Genova which ruled the bandwith a transmitting station could use and what frequency ranges could be used for civil broadcasting.
Unfortunately they defined the space for one broadcasting station very small, so that two senders often messed up each other (9 khz-"piping"). So you had two possibilities: The directional ferrite antenna, (Richtantenne oder Peilantenne, the knob under your volume control), or to weaken the reception, hoping the disturbing second sender will be faded out.
That´s the problem for am.
A weakened FM reception is seldom. Perhaps some radios had problems receiving a sender that blasted to strong.
The tuning sectors of that old beasts are often very sensitiv because of long distances between the transmitting stations.
I used to listen AFN Frankfurt on FM with an old tube set. None of my other receivers were able to fish that weak signal.
Yours
Alex

[solidjackson]

Oh, so I guess it's like a crude MPX system. Where this radio is sitting, hitting that button wipes out the signal completely. Everything works on this radio but, I noticed one of the 6BQ5 plates is running red... a bad capacitor or a short perhaps?

[gadget73]

Or a bad resistor on the cathode circuit perhaps. Something is definitely causing the plate current to be too high though.

[myrgatroyd]

You should check the currents around that valve. By the way you should recap that ole beast at the points with high currents and tensions. This is:
Filter caps (should always be changed)
The cap that couples one system of EABC 80 to EL84 (pre stage to last stage)
Caps that rule the current and the tensions to the plates
Cannot explain better because of my english.
But remember: Your gear is over 50 years old, and some caps (especially those sealed with tar or those little nasty beasts printed with WIMA should be changed without hesitating. They are known to be down after all this years.)
I strongly advice you to do that. You don´t want your house to be set on fire cause of a 5´column german radio?
Seriously: You are messing around with high currents, and the siemens is very easy to recap. It hasn´t got many of them, and you have a lot of place under the chassis. Also you have the whole documentation. That´s worth a lot. If you need help with the german expressions I would be glad to help you. Good luck!
Schatulle means a little box used to store jewels and treasure. That´s what you got. So take good care of your baby.

Yours
Alex

[jeffsod]

Very good advice there Alex!

[myrgatroyd]

In the last years I got ca 20 radios from this aera, and only two of them worked correct. The others had problems with their caps.
ERO, Hydra and WIMA can be thrown out without checking them. They are simply bad.
That is my experience.

[Sandy G]

Originally Posted by jeffsod

Very good advice there Alex!

Uhh-Huh. Couldn't say it better myself...

[myrgatroyd]

Thank you, Jeff and Sandy... there are so many mistakes to be made, why make always the same ones? That would be boring.... grin.

[solidjackson]

Thanks for all the replies. Fortunately (or unfortunately) no capacitors seem to have the markings like WIMA... most of them have the Siemens logo and are relatively small by mid-50s standards. One of the electrolytics on the 6BQ5 was off by about 20uf, so that isn't a good sign.

[myrgatroyd]

Those tar-sealed praline´s and wax-sealed bonbons tend to get dry. So they short the circuit or don´t allow any current to pass (in extremes). Check them out. No matter what the marking is.
That cap you checked shurely is not the only one working out of tolerance...