From: legg@nospam.magma.ca   
      
   On Sat, 29 Nov 2025 12:47:21 +0000, Cursitor Doom   
    wrote:   
      
   >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.   
      
   Troubleshoot in the 'off' position and assume that AGC has nothing   
   to do with your problem.   
      
   RL   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)