Derry Posted February 25, 2009 Share Posted February 25, 2009 Yes, it's been a bumpy few days for the ol' fish tank. After two pump failures in two days and the loss of a green monti to agents unknown, I noticed today that two of my T5 bulbs aren't coming on. I'm running a Tek Light with six 48" bulbs. All of the bulbs are less than three months old, and the fixture itself is less than two years old. The attached graphic shows how the two outer lights are wired together as a unit, while the four inner lights are wired together as a second unit. The two bulbs in the inner unit marked with a red X aren't coming on. I swapped a working bulb with a non-working bulb and verified that the problem is with the fixture, not the bulb. Can anyone tell me what might be causing this and how to fix it? I'm not a total electrical noob, but I've never cracked one of these light rigs open before, either. Thanks! Derry Link to comment Share on other sites More sharing options...
Entropy Posted February 25, 2009 Share Posted February 25, 2009 That is a pretty odd wiring setup. How many ballasts are there? My first guess would be a ballast going south, but it might also be the wiring or a loose endcap. Link to comment Share on other sites More sharing options...
Reybeast Posted February 25, 2009 Share Posted February 25, 2009 never cracked one of those open, but the best solution is to probably rotate the end caps with known good ones one at a time (with the power off of course). In other words, take a working endcap from one of the working bulbs and swap it for a non working bulb's endcap. I know that sounds like a pain, but it seems to be the only way to first rule the end caps out. Then you're looking at wiring or a ballast problem. Link to comment Share on other sites More sharing options...
Derry Posted February 25, 2009 Author Share Posted February 25, 2009 Hey, Entropy! Actually, it's pretty common on these T5 systems. I've got two power cords and two power switches in order to control the inner and outer groupings separately. That way you can create a dawn and dusk effect by timing the two outer lights to come on earlier and stay on later than the four inner lights. I'm assuming two ballasts, one for each grouping, but I'll have to pull the casing off to be sure. Rey, thanks for the tip. I'll take a look and see if it's possible to shuffle the end caps around. Link to comment Share on other sites More sharing options...
Entropy Posted February 25, 2009 Share Posted February 25, 2009 I am guessing you are right on the two ballast theory. That should actually rule out the ballast and leave you with either the endcap or wiring, although if the four bulbs are wired together I am not sure why two are working and two are not, unless that side you are seeing is the neutral, and the hot is hidden on the other side (two bulbs per hot wire). Hopefully a wire just pulled loose or an endcap came apart and it will be an easy fix. Link to comment Share on other sites More sharing options...
Derry Posted February 26, 2009 Author Share Posted February 26, 2009 So it turned out to be a bad bulb after all. When I swapped out one of the non-working bulbs for a working bulb, I had the bad luck of swapping a good bulb for a good bulb. I simply got lucky while troubleshooting the rig after taking the reflectors off and loaded up four good bulbs into that middle set. After some more noodling, I figured out one of my actinics wouldn't fire up, and that was preventing the bulb paired with it from lighting up, either. Note to self - when two neighboring bulbs fail to light, swap BOTH bulbs to confirm that the fixture is working, and go from there. Link to comment Share on other sites More sharing options...
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