Hellfax - Transceiver HF 146  
Facsimile devices transmit documents with only black and white pixels, i.e. Texts and drawings.
When operating as a transmitter, the document to be sent is mounted on a drum,
the scanning unit, attached to the optics carriage, is beeing pulled by a flat belt
along the rotating drum. The scanning light is directed on the drum from above,
and the reflected light is converted into electrical signals by means of a photo cell.
The signals representing the black and white pixels are then sent over the transmission line.
Klein Fax KF 108 Datenuebertragung
When operating as a receiver, the received electrical signals actuate a tiny inked
recording wheel by electromagnetic force, which writes the black pixels on a sheet
of normal paper mounted on the drum.
  HF 146 1970 catalogue    catalogue (German)                    
  HF 146 und BS 109 1973 catalogue (German)  

Transmission sample   (HF 146  1970)


   Fax samples: Originals dated on the years 1970


The aim of the repair: a functioning pair of fax devices
By using different components from the existing equipment, we are approaching this goal,
however: three components have to be renewed:
- the drum drive belt: it is still available from specialist dealers
- the drive wheel of the ink ribbon drive of all devices is defective
- the flat belt that moves the optics carriage has come loose
The drive wheel of the ink ribbon drive has been renewed by our association member
H. Karius
Thanks to the support of the HGS company, the Continental company cut these two flat drive belts, which were taken out of production a long time ago    

The core:

The writing unit







After repair work:

      Transmitter serial number     
  121574       7416457
Test transmission after the rough adjustment of the printing head
Test transmission after the fine adjustment of the
printing head
   7416457       121574
       Receiver serial number    



Preparation for the repair work:

Various fax machines were inspected for functionality.Especially those components
made of plastic have suffered a lot after 50 years. These have become brittle or have
turned into a tough mass. The pictures in the following picture gallery were taken
during the examination on various fax machines.