TELEFUNKEN FE270T ELECTRONIC CHASSIS 209 INTERNAL VIEW.

The TELEFUNKEN CHASSIS 209 Is a Hybrid technology type.

There are 3 Tubes employed in Frame deflection, Line deflection and Line oscillator stage.

- EL504
- ECL805
- ECH84
Was one of the first TELEFUNKEN sets eliminating the 2 selectors drum tuner tuning system replacing them with mechanic keyboard tuners and semiconductors tuner unit developed.

This invention relates to a keyboard for presetting the tuning of a television receiver receiving apparatus, comprising a tuning setting member manually operable for setting up the tuning for the reception of a plurality of transmitters and a group of depressible keys. More particularly, the invention relates to a keyboard for a television receiver receiving apparatus to be used at home domestically, known as television receiver, wherein each key is associated with a tuning storing element adapted to cooperate with the setting member in such a manner that in a first condition of the key said element is conditioned to store the tuning preset by said member and in a second condition of the key the element automatically sets up said member according to the stored tuning.
The main object of the invention is to provide a keyboard for a television receiver receiving apparatus, wherein the tuning setting member cooperates directly with the tuning storing element, whereby the tuning is memorized with a very high precision, while requiring a reduced space. To this end, according to the invention, each tuning storing element includes a wedge pivotally mounted with respect to the associated key, the tuning setting member being provided, in correspondence with each one of said elements, with a pair of converging tapered profiles adapted to cooperate directly with the associated wedge.  Such keyboards for radio and television sets are per se known. They comprise keys of variable lengths, fitted with cams, which can be locked in position, each position corresponding to the tuning of the receiver to a given frequency, and control means, which, upon the actuation of one of the keys, transmit this position to the tuning circuit of the receiver. However, the known keyboards of this type occupy a considerable space, which forms a disadvantage where, as it is the case with motorcar dashboards, space is at a premium and therefore the opening or receptacle allotted for the installation of the receiver therein is of necessity small.

The Flyback Boost diode is a selenium rectifier and also the EHT Rectifier.


The EHT selenium rectifier which is a Specially designed selenium rectifiers were once widely used as EHT rectifiers in television sets and photocopiers. A layer of selenium was applied to a sheet of soft iron foil, and thousands of tiny discs (typically 2mm diameter) were punched out of this and assembled as "stacks" inside ceramic tubes. Rectifiers capable of supplying tens of thousands of volts could be made this way. Their internal resistance was extremely high, but most EHT applications only required a few hundred microamps at most, so this was not normally an issue. With the development of inexpensive high voltage silicon rectifiers, this technology has fallen into disuse.