Restoration of a german bakelite phone W49

[Volker]

A few years ago, I got two W49s that had been stored in cardboard boxes in a drafty attic for decades. The phones dated from the mid-1950s and were a standard model in post-war Germany. The special feature was that the housing could be mounted both as a desk phone and as a wall phone. It depends on how you mount the dial and hook.

Restoration of a german bakelite phone W49

W49  in Wikipedia

The base plate is made of thick sheet metal and the handset is heavy. The phone could not be carried around and the heavy handset caused pain in the arm after long phone calls.

The whole construction with its solid bakelite case seems to be built to last for centuries. The case was just filthy and could be polished up with rubbing and cleaner for car paints and looked almost like new afterwards.

After a few years, the coupling capacitor for the bell broke on one of them. This was a paper capacitor that had been potted with tar in a sheet aluminum case. Using a heat gun, it was possible to melt the tar, pull out the old capacitor and replace it with modern plastic film capacitors. The appearance had not changed as a result of this procedure.

On one specimen, the dial mechanism was almost like new. On the other phone, it was heavily soiled and worn out. After many hours of cleaning and adjusting, dialing finally worked flawlessly.

[Volker]

When I opened the phone for the first time, I found that it was bugged. I had photographed it as proof.

[dsk]

Volker
You are so welcome to the forum, and thank you for your great pages.
Everybody should take a look at those: https://elektronikbasteln-pl7-de.translate.goog/?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=en

I have learned a lot from you, and I use the same software for my dials.
I have learned that the pulses may look wrong if I measure on the phone line with ringers, capacitors etc, but the speed seems to be right even that way. Disconnecting the dial and measure only the dial makes perfect readings.

The W49 is a special phone, combined wall/table top. You came out with a very nice result.

Regards from Norway
dsk

[countryman]

Great! A bugged phone... must have been some eastern secret service!



in the lower right corner there is an interesting thing, an approval stamp. These were introduced pre-WWII to assure  material quality. Who can see the stylized letters M P D (Material-Prüfungsamt Dahlem)? A number of Bakelite phones had the stamp into the 1950ies.
WA should be the manufacturer of the shell, Schwarz-Punkt-Geräte, near Munich. 31 is -according to another source- a newer code for Bakelite filled with wood flour. The 1? I don't know 
For further research: https://www.radiomuseum.org/forum/pressmarken_praegezeichen.html

The metal part has a different stamp.