by Socratic Monologue on Mon Apr 16, 2012 4:00 pm
Any instant start ballast can be used to overdrive fluorescent lamps. That said, what starboard is doing is not exactly overdriving (at least in the sense used by most folks who, like me, use creative wiring schemes to drive NO lamps at HO and near-VHO wattages and outputs). Rueg, unless you have some evidence or electric theory knowledge to suspect driving a 39w lamp with a 54w ballast to be dangerous, I'm going to respectfully disagree with you. I currently drive 32w T8 lamps at upwards of 60w with no ill effects, and have for years, as do many people (planted tank folks do this often).
Starboard, you don't need a ballast by the same manufacturer; any appropriate wattage T5HO ballast will do (in fact, upgrading after a ballast failure is a good time to do so). But, I know of no reason why that 54w ballast shouldn't drive your lamps just fine. If you want to troubleshoot the thing, here's how I'd proceed:
-- hook the new ballast up to a circuit you know works. This will test to see if the ballast itself works.
-- hook up one of the ballasts you have that you know works (that is, one of the other ballasts in the fixture) to the circuit that you currently have the new ballast on. This will test all the components of that circuit -- the lamps, the wiring, the sockets, the switch.
Either you're going to find that your new ballast doesn't work, or that some component of the circuit is shot. If the latter is the case, I'd get a cheap multimeter and test each part for continuity. If you don't want to get a MM, you could try bypassing the switch to see if that's the bad part, but testing wiring and sockets might be harder without a meter.