I have bought 6 of these beauty's and never have they malfunction. I once had a problem like that but what worked for me was adding the right voltage for the lepai. I bought one from amazon on the "what other people also bought". I think is 12 volt I don't remember. I'll have to look when I get home from work. Hope it helped. To bad I can't help on the returning part
Take it to a local radio shack to see if they have a power brick you can test it with, make note of voltage, amps, etc it uses. Mine worked perfectly fine but I've had other Chinese electronics that forgot to do the quality test process and came with dead power bricks.
The exact thing happened to me. Not all sauder points were saudered. Sorry I don't have a fox. I bought a different unit when that happened. Maybe try resaudering the points? You may have fried the board