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Episode 1 - Swiss Army Feldtelefon 50

Description

The Swiss Army field phone "FTf 50: Feldtelefon Modell 50" was developed by Albiswerk Z├╝rich AG (The Swiss Siemens subsidiary, later renamed to Siemens Schweiz AG) in the late 40ies. It's design was inspired by the US EE-8 field phone. With 2.6kg (5.7lb) the instrument was very lightweight for it's time. The Swiss Army predecessor "FTf 47: Feldtelefon Modell 1947" was weighing in at more than 9kg (20lb).

Albiswerk delivered about 10000 pieces to the Swiss Army between 1950 and 1960. Another about 3000 pieces were delivered by Gfeller in the 60ies (The instrument in the Video was manufactured by Gfeller).

The instrument was also delivered to the Swiss Civil Protection Service and to the Dutch army as "Veldtelefoontoestel TA-3001".

Unique features

Datasheet

Magneto repair guide

At truefork.org you can finde a very good repair guide for a common problem of some of the FTf 50 magnetos. With age the centrifugal force switch gets stuck and the magneto coil is always shortened, resulting in stiff cranking and not generating ring current.

Gallery

Ready to use.
Disassembled

Disassembled
Disassembled

Top to bottom: Line connectors, battery cutoff lever, battery compartment, openings for ringer.
Disassembled

Folded crank.
Disassembled

Top to bottom: Line connectors, Two pairs of replacement screws, Color coded handset microplugs, capacitor, small and lightweight generator, bell covering the combined ringer and induction coil.
Disassembled

Electrical diagram (On lid outside, german and french)
Electrical diagram (On lid outside, german and french)

Wiring diagram (On lid inside)
Wiring diagram (On lid inside)

Handset. P.T.T. lever. Rainproof.
Wiring diagram (On lid inside)

Handset with elements out.
Wiring diagram (On lid inside)

Handset microplugs.
Wiring diagram (On lid inside)

RX element. Specific size for that handset modell.
Wiring diagram (On lid inside)

RX element. Specific size for that handset modell. That one made by autophon.
Wiring diagram (On lid inside)

TX capsule, initially PTT standard 1946 carbon transmitter, later updated to dynamic in the 80ies, made by Philips.
Wiring diagram (On lid inside)

Look inside, battery cutoff lever in center.
Wiring diagram (On lid inside)

Handset stowed.
Wiring diagram (On lid inside)

Ready for transport or storage.
Wiring diagram (On lid inside)

Sources


Creative Commons Attribution-ShareAlike 4.0 International License

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