From: cd6699@notformail.com   
      
   On Fri, 28 Nov 2025 19:05:31 +0000, liz@poppyrecords.invalid.invalid   
   (Liz Tuddenham) wrote:   
      
   >Cursitor Doom  wrote:   
   >   
   >> On Fri, 28 Nov 2025 11:37:56 +0000, liz@poppyrecords.invalid.invalid   
   >> (Liz Tuddenham) wrote:   
   >>   
   >> >Cursitor Doom  wrote:   
   >> >   
   >> >>... Time for someone else more experienced with Uhers to take over   
   >> >> methinks.   
   >> >   
   >> >I used to repair them many years ago.  if you live anywhere near Bath,   
   >> >drop in and I'll try to help you.   
   >>   
   >> That's very good of you and I would - but unfortunately I left the UK   
   >> many years ago. Thanks, anyway. :)   
   >   
   >I'm sure I had the circuit diagrams for several of the Uher models - but   
   >i have no idea where they are now.   
   >   
   >I seem to remember the 2-transistor mic pre-amps had a rather clever   
   >counter-intuitive volume control arrangement, which gave a wide range of   
   >possible volume input levels.  The wiper was connected to the output of   
   >the second transistor, with one end of the track going to the followiong   
   >stage and the other end going to the emitter of the first transistor.   
   >As the volume was turned down it increased the negative feedback around   
   >the front end.   
   >   
   >If you suspect the fault is in the AGC system, do you get an improvement   
   >if you switch the AGC off?   
      
   Doesn't bring the audio back, I'm afraid. However, that doesn't   
   exculpate the AGC, as they've embedded the on/oiff/fast/slow switch   
   right in the middle of the stage.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)