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HELP! Herpsitting & the UVB Light is on the Blink!

Discussion in 'Habitat Lighting' started by phip, Jan 5, 2012.

  1. phip

    phip Member

    Hello; I'm not a reptile expert so forgive my lingo and all...

    I'm watching a bearded dragon for a friend of mine who is out of town for a month. From what I understand she's been though all kinds of light drama in the last few months: the pet shop stopped carrying the brand she was used to and the bulbs she got from them after that lasted only a few weeks to months. Now the drama is mine.

    She went and got a replacement bulb before she left today. Naturally the clerk convinces her she needs a new enclosure too. She gets it home and it flickers off and on horribly. She takes it back to the pet store where the clerk plugs it in and it works completely fine, naturally. Embarrassed, she brings it home where it starts to flicker again, naturally.

    I know a fair bit about electricity and did everything I could think of to try and isolate the problem. I unscrewed the base and checked the wire terminals are tight, looked inside the switch enclosure, checked the tab inside the socket is contacting the bulb tip. Nothing fixed it but since the problem happens at every fixture in the house, and her red heat lamp in the same outlet has no problems, we took the fixture back and exchanged it.

    Here I am again, the light still flickers on and off. The fixture is a Zoo Med Deep Dome Lamp Fixture, LF-17. The bulb is a EXO-TERRA Solar Glo 125W PT2192. I found a thread here, Exo Terra Solar Glo Faulty? that seems to describe my problem. When I turn my light on cold, it works for about a minute before the flickering starts. The fixture doesn't even feel warm yet! If I put a regular incandescent bulb in the fixture, it works fine.

    I'm at a total loss for what to do. The wiring in her house IS rather rickety, but I don't think that's causing this. My main culprit is the cheaply made bulb, but I'm afraid since everything we've tried so far has failed to fix it.

    I just want to see my friend's lizard basking happily and be able to relax! Does anyone have any ideas?!
     
  2. mld

    mld Subscribed User Premium Member

    Is the fixture on an angle at all, Mercury Vapor Bulbs are very temperamental when they are hot, they need to be straight and cannot be moved while hot, like lifting a lid.

    Do you have a photo of your friends setup, and what size tank is it being used in L x W x H in inches please?
     
  3. justor

    justor Elite Member

    I have been using that same bulb for about four months and haven't had any problems like you describe. I do remember reading in the safety manual that if the bulb is moved too much it will shut off, and I think it has a feature which prevents it from being turned on for like 10 minutes or so every time it turns off. Is the fixture clamped at an angle or sitting right on top of the enclosure? It should be resting completely still and should point straight down.
     
  4. phip

    phip Member

    Ah, this may be. I can't take a picture right now but it is maybe 36"x18"x20" or thereabouts. probably a 50 or 65 gallon tank, with a metal mesh lid. Uh... not clamped at all, the lights are sitting directly on top. They are pretty much flat, but obviously not perfect.

    Hmm. I wonder if I can rig up a mount on the cheap...
     
  5. phip

    phip Member

    Is it more likely the bulb is permanently damaged or just unhappy with its environment?
     
  6. AjaMichelle

    AjaMichelle Elite Member

    MVBs that aren't mounted properly have a much shorter life span overall.

    If you have the light pointing directly downward then it shouldn't flicker anymore. You say that the lights are pretty much flat, but not perfect, so does that mean they're still angled somehow?
     
  7. phip

    phip Member

    I made it sound that way but no, I'd say they're totally flat. Definitely no noticeable lean. The mesh is just a little wavy, compared to a table top.
     
  8. murrindindi

    murrindindi Elite Member

    Hi, sometimes the metal "prongs" that make contact with the bulb at the base of the ceramic bulb holder get pressed down, have you checked that? It`s easy enough to just lift them slightly with a small screwdriver.
    EDIT: Just for the sake of asking (nothing to do with the flickering); how far is the lizard from the bulb when sitting on the basking spot?
     
  9. Vers

    Vers Elite Member

    As stated MVBs should always be mounted facing straight down where it cannot be moved or bumped while on, this means a screen top is not an ideal place for one to be resting directly as it would be constantly moved to access the tank. Still, I'm not sure why it appeared to work fine at the shop but not at the house which leads me to believe it's an electrical issue with the outlet and not the fixture. How long was it running at the shop compared to at her home? Was it in the same fixture?

    Also, one thing to note, these bulbs should not be touched with your bare hands. If you have done so it would be a good idea to take a dry cloth or tissue and wipe the exterior surface to remove any oils.
     
  10. Vers

    Vers Elite Member

    At first I thought this may have been the case as well, however the OP did state he checked the contact tab when he disassembled the fixture.
     
  11. Moshpitrockchick

    Moshpitrockchick Subscribed User Premium Member

    One thing that I have noticed with my MVB's is that if they do flicker and I leave them be they usually stop after they've been on for 10 or so minutes. Have you left the light on and let it warm up?
     
  12. murrindindi

    murrindindi Elite Member


    Hi, I`ve never heard of not touching them with bare hands (obviously not when switched on), I often unscrew mine, never had any problems? (unless someone was literally dripping with sweat (or perspiraion for the ladies)! ;)
     
  13. Vers

    Vers Elite Member

    From what I understand oils, salts and or dirt from your fingers can shorten the lamps lifespan. I know this is the case with a few other types of bulbs (certain halogens) and remember reading that MVBs were the same way.
     
  14. murrindindi

    murrindindi Elite Member

    Yes, I read that, but inside my ceramic fixtures there are three tabs, two on the side, and one on the bottom, if one of them isn`t making good contact, it might cause the flickering, though of course, I don`t know how many tabs are in the OPs fixture? (Just a thought).
     
  15. Vers

    Vers Elite Member

    No doubt :) I'm still wondering if the same fixture was used at the house and at the pet store....
     
  16. phip

    phip Member

    I wondered about the flickering settling down when it got warm. I didn't leave it on indefinitely because I was afraid the bulb would burn out. It starts out steady, then after about a minute it begins to flicker continuously. I've let it go 5 minutes. It spends as much time off as on and never really gets warm.

    The fixture only has one tab, in the middle bottom.

    I wasn't there when the light was demonstrated in the shop, apparently the salesman moved it around.

    I'll wipe the bulb down to avoid oils, but I can't imagine that alone would cause the light to act up so badly.
     
  17. schlegelbagel

    schlegelbagel Frog Lover Premium Member

    can you pick up a new ceramic dome (run you about $15 at the petstore) and see if that makes any difference? If not, save the receipt and take it back.
     
  18. Vers

    Vers Elite Member

    You can also check out any large hardware/supply store (lowes/homedepot/walmart) and find cheaper 10" 'work light' housings as well. Just make sure the socket isn't plastic. If that still doesn't do the trick take the bulb to your house and test it there using both fixtures. Process of elimination is your best friend :)

    And fwiw cleaning the bulb most likely will not affect short term performance (i.e. flickering) but it may help in the long term.
     

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