Ballast issues

[TimmyT123]

Hello, I am new to this forum and am seeking advice. Recently one of the ballasts in my coralife 21" (I think) hood burned out, so I bought a replacement ballast. The original was a coralife BH-APL0551A 1x65w ballast and the replacement I got is a Current SL60T 1x65w ballast. Well, when I wired the replacement up it started and powered the 65w 21" bulb just fine but after about 20 minutes of being on I started smelling a burning electrical smell and upon closer inspection the varnish that the electrical components were covered in had a burned hole in one spot. Does anyone know what happened? I do have electrical experience and have replaced ballasts before and to the best of my knowledge this ballast should have worked fine. Do you think the replacement I bought was faulty? Should I buy a different kind of 65w ballast? Thanks.

[gregony]

I think the ballast got hot. But seriously, any way you can send a picture showing the wiring detail that you did on the ballast, and the ballast wiring diagram?

[TimmyT123]

I can't get a picture of how I wired it but here's what the ballast looks like.
65 Watt Current Raw Power Compact Ballast PL55W-65W*1 Model SL60T Part 1764
To me the wiring diagram is kinda vague so I just wired it to where the two red wires went to the right two pins on the bulb and the blue wires went to the left two pins. If I had wired it wrong would it have even worked? Thanks for your help.

[gregony]

That's a pretty straight forward wiring diagram on that ballast. If you wired the black (which is the line) and you wired the white (neutral) to their respective colors you shouldn't have messed up that part. The ballast does say the ground has to be connected. Make sure you have the case of the ballast connected to the ground of the AC inlet cord. If you have an ohm-meter you can measure to make sure they're connected. If no meter, then you have to eyeball it.
I'm not sure what sides go to which side of the lamp, is it the top or the sides that the blue and red group to? I don't know? If you did it the same way the corallife ballast was, it shouldn't be a problem.
The short answer on would it have ever worked if it was wrong is yes it could have. But probably not, if you had messed up the wiring to the light. In other words, the red and blue are almost certainly going to the right place since the bulb lit. If you switched the line and the neutral, the ballast would probably still work, but depending on the front end circuitry it may not work for long (which would match your symptoms). Also, if the ground wasn't carried through, that could cause the same problem. If you verify the front end (the AC IN) wiring, and it's correct, you probably just got a bad ballast. Verify that the label on the ballast matches the label on the website COMPLETELY. If they sent you a 220V or a 50Hz ballast instead, it might work for a while, then the switching FET would burn up. We had an ME put a 220V ballast in a fixture at work one time (not paying attention) and the light worked fine for about two hours and then the ballast smoldered to a stop.
Either way, you probably need to send it back.

[TimmyT123]

Ok, I think I've found the culprit. The whole hood is grounded so that's not the problem. There is a section of wire in between the main power cord and the ballast and it turns out that, that section of wire was reversed where it is spliced to the power cord! So this error was not really my fault but rather the factory's! If only I had taken that extra step to check the polarity of the wires all this could have been avoided. Luckily for me, the ballast is under warranty so its all good. Thanks so much for your help!

[gregony]

Hopefully that'll do it!