The above Ad will no longer appear after you Sign Up for Free!

Problem (Maybe) with a leko...

Discussion in 'Safety' started by photoatdv, Dec 27, 2008.

  1. photoatdv

    photoatdv Active Member

    Messages:
    934
    Likes Received:
    32
    Okay, I seem to be starting a lot of threads lately, but hey I'm not in school and I don't have any shows in pre-production (though as soon as I get busy with school I'm sure I will have about 3).

    So, to the real question. We have this one Strand Leko up on the catwalk that seems to be doing the impossible. A couple of years ago I was focusing and I jiggled the socket/cap thingy of this light (which wasn't working at the time). The next thing I know the light flashes on for a second and I'm fairly sure that it somehow shorted from the raised handle looking thing to the grounded housing of the fixture through my hand (it hurt!). At the time I was too freaked out by our TD (I'd never worked with him before and my first 2 hours with him consisted of learning to coil cables properly and he was the first pro I'd worked with) to insist that he look at it. So come focus a couple of months ago ant the same thing happens!!! This time I unplug it to wait til we have time to fix it (the show I was small and I couldn't do anything about it then). Two weeks later we have big dance show, I told our TD (who I now work with a lot and am not the least bit intimidated by --unless I just messed up on something stupid). Bring the light down and meters it, fine; he takes the entire socket/ cap apart and can't find a single thing wrong with it(other than the lamp blew when it shorted)!

    Has anybody seen something like this? How could this be happening? I'm not too worried about that happening again because it hurts, but oh well. What does scare me is that somebody will be holding something grounded with their other hand and this will happen. Saddly, this is very intermittent and whenever I've tried to replicate it it hasn't worked.

    My elecronics teacher did suggest that it could be going hrough the insulation because of the really high current. Is that a possibility? What else should I check for? I'd really like to fix this or at least prove there is a problem (to the best of my knowledge this hasn't happened to anybody else, but I also do most of the focusing) so my TD will stop thinking I'm crazy. Thanks for any ideas anone might have.
     
  2. cdub260

    cdub260 CBMod CB Mods

    Messages:
    1,302
    Likes Received:
    148
    Location:
    Southern California
    My initial thought on what the problem might be is a mis-wired connector with the ground and neutral wires switched. this could be at the fixture, on a cable, or the receptacle you plug the instrument into. To find the problem, a qualified person needs to backtrack the circuit, starting at the fixture until the problem is found. The simplest way to check the circuit or cable is to use a Gamcheck to verify that everything is wired properly.
     
    Last edited: Dec 27, 2008
  3. 1kfresnel

    1kfresnel Member

    Messages:
    41
    Likes Received:
    4
    Location:
    Buffalo, NY
    I agree with cdub260, most likely it's a mis-wire in the connector. If the socket to plug check out continuity wise, with no shorts, they next step would be to verify the receptacle.

    Another area of concern is the physical wiring harness. I've seen plenty of older instruments in venues which have lost their method of retaining the wires, so they begin to rub against the body of the cap. Verify the wire is of proper rating (high-temp), and is free of any signs of physical or thermal stress.
     
  4. photoatdv

    photoatdv Active Member

    Messages:
    934
    Likes Received:
    32
    We did check the wires in the cap and all is good. That is a good idea about checking the recepticle. The really puzzling part is that I have tried to replicate this problem and it doesn't work, yet it has happened on two different occasions (and no I was not on anything at the time or ever!).
     
  5. dramatech

    dramatech Well-Known Member

    Messages:
    466
    Likes Received:
    111
    Occupation:
    MASTER ELECTRICIAN
    Location:
    Winter Haven, FL
    you didn't mention what type of lamp socket is in the instrument. In many of the older prefocus sockets, there is an insulating piece that sits below the socket and above the metal mount. This insulator after many years of over heating, can break and fall out. This will allow the hot pin to make contact with the metal mount. Usually the problem only has conseqences when changing the lamp with it electrically "hot", but there is a spring that can become weak and allow the hot lead to touch the frame. If it is a socket that has screw leads for the wires, I would take it off the mount and give it a thorough inspection for any mechanical stress, or frayed wires. And of course do all of this with the instrument diconnected from any power.
     

Share This Page