Problem with audio from left rear channel JVC receiver

It was intermittent at first. Now it's just not there, ever. Any idea
what the problem might be? Or what it might cost to repair?

I've checked the problem with other speakers, inspected the wiring and
connections, etc. Still, nothing.

 

If only one channel is out, then the amp for that channel has most likely
gone west (power supply and other stuff are probably OK ). Could be an IC
or a power transistor or lots of other things. Takes some troubleshooting
skills to sort these things out. Easy problem for those who know how to do
it since there is a working channel which can be used as a reference.