Gary Crossman

I bought a bunch of these slightly used 2.1 systems for resale. I've tested 17 of them so far and every one has a dead left channel. I've mixed and matched speakers, wires, etc. and come to the same conclusion. The left channels from the subwoofer don't work. On one of them, I took the control pod apart and reseated the large wire with no luck. Can anyone help? I'm desperate!