View Single Post
  #1   Report Post  
Posted to rec.audio.pro
Brian Brian is offline
external usenet poster
 
Posts: 14
Default Need help diagnosing bad mixer channel

I have a little Yamaha 8 channel mixer, about 3 years old, that I use
for live performances, and channel 1 is malfunctioning. I'm hoping
this is something I might be able to repair myself, I don't want to
spend a couple hundred bucks having a $300 mixer repaired. I also
don't want to buy another mixer. I'm fairly handy with a soldering
iron, and have a cheap multimeter and rudimentary electronics
knowledge. I use this mixer frequently and I'm hoping I can perform a
satisfactory homebrewed repair to get it back in action.

The symptoms: The input and preamp seem to be working, but there is no
signal getting to the main outs from this channel. I can hook up a mic
or instrument and see the input level on the LED meter, but when I
un-mute the channel there is no sound from the main outs. I havn't
tried to see if the aux sends are getting a signal from it yet.
The gain pot works but seems 'weak' compared to the other channels, ie
I have to turn the preamp gain up pretty high on this channel to see
the same levels on the meter as a much lower gain on the other
channels.
I don't know if this could be as simple as a connection came
unsoldered inside, or if an internal component might actually need
replacing. What are some possibilities, and what non-obvious things
should I look for when I open it up? Things I can test with the
multimeter?

thanks,
Brian