From: @noway.com   
      
   Jack wrote:   
   > This is a great piece with one little problem. Often, when switching the   
   > unit on, the left channel is out, no sound. Turning the volume up always   
   > kicks it in. Often the volume has to be turned up severely to accomplish   
   > this so I tried doing it with the speakers switched off. Switch off   
   > speakers, turn volume up to max, turn volume down to min, switch   
   > speakers on, turn volume up a bit and the sound is back in both   
   > channels. In addition, after getting both channels to work, after 10 to   
   > 20 minutes, give or take 5, the left channel goes out again.   
   >   
   > This behavior lead me to suspect the volume switch, so I flooded it with   
   > switch cleaner and worked it, but to no avail. Problem persisted. Next I   
   > checked all the cold solder joints and found one that was loose. I hot   
   > soldered ALL the cold solder joints. Problem continued. Today I used   
   > some cables to switch the PRE OUT channels into the POWER IN channels,   
   > left to right and right to left. The next time the problem cropped up it   
   > was still in the left channel. This is telling me that the problem is in   
   > the left main amp section.   
   >   
   > Given the behavior described above I can only guess that a rise in   
   > voltage in the main amp produced by turning up the volume with the   
   > speakers turned off somehow corrects the condition causing this problem,   
   > but at the moment I don't know what this condition might be. I assume   
   > that with the speakers turned off there is not a lot of current flowing   
   > in the main amp when the volume is turned up, but that the voltage is   
   > increased. As I write this, a dawning suspicion presents itself and that   
   > is: the problem might be with a transistor, as they are voltage regulated.   
   >   
   > Next step is to open up the unit and do a visual inspection, hook it up   
   > to a pair of speakers and turn it on and attempt to compare voltages   
   > along the signal path of right and left channels of the main amp when   
   > the problem crops up.   
      
   I tried probing DC voltages across speaker output and ground at each   
   channel with a digital meter with the speakers connected and unconnected   
   and the readings were essentially the same, under 10 mv, left and right,   
   speakers connected and unconnected. I suspect that this is not an   
   effective test.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)