Capacitor on MH ballast

[yardboy]

I'm using a Holothane 175W bare magnetic ballast with an AB 10000K bulb. The bulb is only two weeks old, and it doesn't always fire when turned on. The vendor told me that AB said these bulbs take a while to "burn in" and to just let it go until it starts firing consistently. Several times its not fired at all after being on all day. Turning it on and off until it fires works if I'm here, but otherwise,...... I've already changed out the ballast to see if that was the problem, though the first was new too.
What I'm wondering is I noticed that the capacitor has two sets of connecting posts. Can two capacitors be hooked up in parallel or series to provide a greater charge to fire the bulb, or am I setting up a bomb if I do that?

[wharyat]

Theoretically it should work great; but in reality I wouldn't trust it 100%. An overloaded capacitor can do some damage.

[Lutrah]

By adding two capacitors in series, you will be reducing the capacitance of that circuit by (C total=(C1*C2)/(C1+C2)) and could possibly cause other problems. By adding another in parellel you will simply add to the capacitance of that circuit (C total=C1+C2). This is by far the safest and most reliable way to add capacitance, but be certain the new one is of suffecient voltage. Keep in mind that by changing the capacitance of this circuit will also have an effect on overall resonant frequency of this circuit... be it good or bad.

That being said, I would have to advise against doing either.

[yardboy]

Thanks Lutrah, sounds like you know your stuff. I'll just continue to curse the bulb! I had a feeling it was a dumb idea.

[jesspaul]

My first thought would be to swap out the switch and if thats not it I would swap the capacitor. The power cycleing to get it to start sounds like either the switch is bad or maybe the cap is leakly.

[yardboy]

Thanks Jess but I changed the ballast and it didn't help. Changed the bulb and it worked fine.