I didn't mess with the connection at a7 at all in the switch.
That wire had to move to change the pots out. It is literally connected to the pot!
Any other ideas on what might make me lose the channel.
I would perform another voltage check to be 100% certain.
Beyond that, you can temporarily solder in a little jumper wire between A2 and A7. That will sum the outputs of the pot and could provide some useful information. If you happen to lose both channels when you do that, be sure to rotate the volume control through its entire rotation to see if things come back in part of the rotation.