Testing fluorescent ballast

[EdT]

I have a two bulb fixture on my blast cabinet. It uses two 15 watt T-8 bulbs much like you might find in a desk lamp. I left it on for a couple of hours and when I returned the lights were no longer working. The ballast is a "trigger" ballast and there is no separate starter. According to the label on the ballast there is a one time thermal fuse which I suspect may have died. The question is, is there any way to check the ballast function before I go buy another one. I know that I have input voltage, but I took readings on pretty much every combination of wires on the output side and I see nothing. I'm a bit naive on electrical stuff so any help would be appreciated.
Thanks

 

[pattenp]

Have you tried new lamps?

 

[Aceman]

Like Pattenp suggested try new lamps first. If that doesn't work replace the ballast. While you are in there replacing the ballast tug on the wires going into the tombstones to make sure they haven't came loose. It's not uncommon.

 

[EdT]

Not yet, but since it went from working fine to not working at all over a very short period, I'm inclined to think that's not the problem. It is, however, the simplest solution, so maybe I should try that first before I get too wrapped up in a complex answer. I' am still wondering if there shouldn't be some voltage output from the ballast when there is power going in. I confess, I don't really understand how a ballast works, but my gut tells me that the bulbs aren't going to light w/o some voltage at their terminals.

 

[wyliesdiesels]

Are either or both bulbs slightly black at the end?

 

[EdT]

The bulbs have no discoloration at the ends.

 

[rockwithjason]

Without special equipment there is no good way to check ballast output. As mentioned above it is very common for the wiring to come loose at the tombstone sockets. Other than loose wiring you are at bad lamps or bad ballast. My money is on the ballast

 

[jhelrey]

The trick is with the light on, take a voltage detector and touch where you put the pins of bulb in. If it lights up, its bulbs. If not, it's ballast.

 

[EdT]

Got a new ballast. it works fine now.