Chosen Solution
Anyone else ever debug and fix a problem like this? The output has lost the left signal. I verified the input is stereo with my oscilloscope. I tested many of the 24 channels, all have the same issue. I tested and get the same results using the 1/4" input or the microphone input – stereo into the input, but mono on all outputs. Not only do all the outputs only have the signal on the right pin, but I also tested the Send Pre and Post from right near the channels themselves (i.e. channel 24 as pictured), and even those have lost the left side! Model: Peavy Mark IV 24-Channel Commercial Mixer (also comes in 16 channel) Manual: https://assets.peavey.com/literature/man… Can anyone help narrow in on where the problem might be? I can’t find a schematic online other than what’s in the manual linked above, but that’s not really a schematic, but a block diagram instead. I have the board open and see all the various boards inside. I’m hoping I can isolate the board with the issue, then isolate the component. I have good tools for testing. Here’s a basic picture showing one of the tests described above. All the inputs are working the same: I verified stereo is coming in (both 1/4" and XLR), but anywhere I test only has mono coming out.
Thanks for your time!
The block diagram is slightly helpful, it does not show left or right so it is showing basic components without a lot of detail. The first step is to unplug the mixer, open the covers and do a visual inspection, look for burn marks and discoloration of components and PCB, check soldering connections and wiring. The next step requires caution as electrical shock is a risk, turn on the mixer and work your way back from the output to the internal amplifiers, the circuit should be symmetrical enough to compare left and right. From your description, the problem may be in the preamp. The oscilloscope can show you the signals along the way, if it is a 2 channel scope then that will help compare right and left. Hopefully, a visual inspection will help narrow the scope action to a small area.
Hola espero que esto ayude.
