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.   
      
   When the left channel drops out I can bring it back by pushing down from   
   the top with a chopstick on the circuit board that contains the input   
   selector buttons. I can then make it go out again by pushing up from the   
   bottom on the same circuit board. After doing this several times, the   
   channel comes back to stay... until it goes out again, which could be in   
   the next ten minutes or ten hours. Also, pressing the input selector   
   buttons at random also brings back the left channel. The puzzling   
   behavior comes in when I switch channels at the PRE OUT/POWER IN jacks.   
   If the problem is in the push button switches, the dropped channel   
   should change from left to right, since the switches are upstream from   
   the aforementioned jacks, but this does not happen. The dropped channel   
   continues to be the left channel. I just don't understand how this could be.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)