Creek 5350SE amplifer left Channel dead

It's the ribbon cable that is likely at fault. There are actually three computer type ribbon cables in the amp. I believe the cable that is responsible for the drop-out of a channel is the widest (longest) of the three, but you really need a tech to look at it and replace the cable. But please note that the new cable may also have defects in manufacture and that it may take some time to order a new cable from Creek. I had a tech solve the problem permanently by removing all three ribbon cables and then hard-wiring the connections together - that is to say, point-to-point wiring. My cost was about $250, but as you can imagine, there is extensive labor involved. Good luck!

Did you check the fuse?