Sony STR-DE325 Receiver Problem?

I am using my speakers connected via the front speakers panel on the back of the machine, I don't know if it matters but they are connected as left and right using "A". So, my left speaker is playing fine, but the right speaker is so weak that when I turn the volume all the way up it still sounds very low. My dad fixed this once but I don't remember how he did it... any Sony gurus out there?