Coralife Electronic Ballast Problem

My wife and I have a 50 gallon marine reef tank, and we bought a
Coralife Retrofit Light Set with 4 65W bulbs (two 'white' and two
'blue). The problem is that one of our 'white' bulbs won't come on, and
I think it is something to do with the electronic ballast - the wire
that comes out of the back of the ballast that the wire coming from the
bulb plugs in to. Has anyone else experienced this problem and solved
it? I'm just wondering if its an easy fix or if the whole ballast is
shot and I need to return it. Thanks!

Joe