Having trouble with 4 lamp flurescent light. The 2 center lamps do not work. Bought new lamps, still do not work. I took the cover off and there is 2 ballast. I noticed that one of the ballasts black and white wires were not connected to the power source. This is a new house therefore this is the first time I have had to change the lamps. The question is, should both ballast be connected to the power. I put the 2 new lamps on the outside and they work and now have this feeling that the fixture was installed to have only 2 lamps and 1 ballast wired.