GPO DYNAMOTOR No 50A, 1970's

Dynamotor for generating all the tones necessary in a telephone exchange including the voltage for the ring signal.
also the tones including, Park, Busy and Number unobtainable etc.

This item can be demonstrated.

Your comments:

• I have the 41a version of this timeless classic. I have been trying to obtain the correct diagram for it now for some months. Iam hopeing to have it working as a demo for the tones. Hope someone reads this and may offer suggestions. Main problem i have is to how to connect the 50v 2amp supply with out the machine "running" away at full speed. Hope there is help out there.
  .......... Dave, Birmingham UK, 28th of January 2010
  
  

A0558