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Follow Spot Bulb Advice

Discussion in 'Lighting and Electrics' started by Shawn P, Mar 11, 2019.

  1. Shawn P

    Shawn P Member

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    Hey everyone, I am looking for some advice regarding older follow spots. A lamp blew (I believe) on tech day and of course we have no spares in stock. It takes an OSRAM HTI 400W metal-halide bulb that costs an eye watering $260.00. The kicker is they're only rated for 250 hours. We're a public school and have very limited funding dedicated to our productions. It's hard to justify replacing it and holding a spare for our other spot when we have other things that we need.

    I know that there are metal-halide to LED conversion kits for commercial lighting, but is there something I could use for these spotlights? It might be more expensive up front, but if I don't have to pay $260 every 2 productions that would be a win.
     
  2. Les

    Les Well-Known Member

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    250hrs on a metal halide?! I double checked and it seems you're right, but that's awfully low. My old high school bought some Altman Voyagers back when I was a freshman and we ran the same lamps the entire 4 years I was there.
     
    Last edited: Mar 11, 2019
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  3. JD

    JD Well-Known Member

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    Currently, there are no drop-in LED replacements for a 400 watt HTI. Due to the nature of LEDs, LED follow spots are generally something designed up from scratch to work with LED technology.
    A little surprised the lamp just blew. Short of shattering, MH lamps generally just get dimmer with age until the point where they are unusable. The inside of the envelope becomes so frosted that it is no longer a point source. You want to make sure it is the lamp that went out. They will look pretty frosted and opaque by about 60% of their life, so don't go by what they look like. Unless shattered ;)
     
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  4. Shawn P

    Shawn P Member

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    Well that is interesting. There is no damage or frost - the op said it just went out. Having never dealt with MH lamps I didn't know what to look for.

    Come to think of it, on the spot the power light comes on but the fan does not. Maybe it's something else electrical. Or perhaps there's a safety switch triggered somewhere. I'll swap the suspect bulb in to our other spot and see if it fires up.
     
  5. JD

    JD Well-Known Member

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    If the fan did not come on then there is something else going on. Many spots have an airflow sensor that will cut power to the lamp if there is no airflow, therefore a bad fan would prevent the lamp from being on. Other spots have a thermal fuse or thermal trip-out so if the lamp began to overheat (no airflow) it would shut the lamp down.
     
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  6. Shawn P

    Shawn P Member

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    So I'm definitely embarrassed, but i really appreciate the thoughtful replies. The fuse on the side was popped. I never saw it! We're back up and running :)
     
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  7. techieman33

    techieman33 Well-Known Member

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    Something I didn't see mentioned is that when it comes time to replace the lamps you'll want to do both spots at the same time if at all possible. Otherwise the spot with the new lamp will be visibly brighter than the other spot.
     
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  8. JD

    JD Well-Known Member

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    Ummm... yes... kind of.
    Unless it was the wrong fuse or the wrong delay value, you have to ask yourself why it blew. Now, sometimes they just do, but if it happens again, there may be more going on. Chances are if it didn't blow right away or within a few hours, there was nothing more that a weak fuse at fault.
     
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  9. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    More reason for me to specify LED follow spots.
     
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  10. FMEng

    FMEng Well-Known Member Fight Leukemia

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    There are several factors to consider. An incandescent or metal halide follow spot has:

    1. A lamp that will fail periodically.
    2. A lamp socket.
    3. A fan.
    4. A thermal or air flow switch
    5. Metal halide has a ballast consisting of an autoformer and capacitor.
    6. A switch, fuse holder, and power cord.

    Most of those components are pretty rugged and easily found or substituted even after the manufacturer goes under. A seized fan is not a catastrophic event unless ignored well past the point the unit gets uncomfortably hot and smells.

    The LED spot has:

    1. An LED array which will become unobtainable in months, unless the manufacturer maintains repair inventory.
    2. An LED driver supply which could be specific to the application.
    3. A fan.
    4. A thermal switch, sensor, or air flow switch (could be designed into the driver circuit).
    5. A switch and cord.

    Depending on the design of the thermal protection, the LED array could fail within moments after the fan seizes. The LED driver supply won't be repairable, just module replacement. The light will not be repairable without factory parts. I would bank on an LED spot being repairable for about 5 years.

    Of course, the proliferation of LED means a rapidly shrinking market for lamps, sockets and ballasts. The incandescent or metal halide spot might be just as hard to keep running as the LED if the basic parts disappear. That's sad because many of us have seen and worked with spots that are older than their operators but still earn their keep.

    For me, it boils down to the purchase price, the lumen output for a given throw, and whether the operators can trusted to handle the occasional lamp change. Everything else is impossible to predict.
     
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  11. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    Don't overlook the noise issue - LED drivers are predictably quieter than ballasts - a high priority in my world.
     
  12. JD

    JD Well-Known Member

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    For now, I would still prefer a followspot that uses a discharge lamp. As the LED market matures, and the products prove their longevity and reliability, my opinion will change.
    Bottom line, when a discharge spot goes down it can usually be up and running in short order with off-the-shelf parts.
    When an LED spot goes down you will probably be shipping big things back to the factory / service center, and be off-line for a while.
     
  13. ship

    ship Senior Team Emeritus Premium Member

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    Depends on your skill level. Did you (in your exception of course), study the manual of the spot you are operating (Most don't). From that, are you trained in changing the lamp (Many are not.) Is the manual for this model and or it's current upgrade readily on hand? Is your skill level up to the ability to follow the troubleshooting advice in the manual in safely doing various tests? I mean it could be something like a dirty or weak fan which needs a sail added to it's micro switch, or such a sail having fallen off, failed micro switch or swith on a cover etc. A lot about a arc source follow spot if it's not running to look at in troubleshooting including house power. Gone out on many service calls... from bad strike wire to sitting in a dark room at the front of the Chicago Theater for many hours outside the spot booth during a show. I was by Union rules locked out of the spot booth, but had to stay in the area because while I was not qualified to run the spots for the show... I was the only one qualified on site to change it's lamp.

    Beyond that.... this ballast was just tested last week, we just serviced the lights... why is it now tripping the breaker and causing a buzz at the breaker panel? Why are both of the spots doing it? Answer, a quick inspection of the bottom housing assembly shows that one each of the removed for cleaning fans were plugged in backward at the Molex plug.

    Been on a site survey where the house switch operated follow spots were no longer working as part of the potential job to fix. Flipped the switch for local/remote and suddenly the spots turned on...

    I have studied the manual for the Strong Super Trouper in various upgrades, read at least one manual for the Gladiator, read multiple times the Lycian 1290, and at least a few times the the manual on 1271 and 1272 but never the M2 or 1295 manuals. As with not having read the Lancelot or I think another fixture manual. I mostly advise on the other spots for repair or buy the parts.

    So all that above... LED's are at least as dependable as arc source lights. If they currently are bright enough for the needs, and provide a good beam of light... not going LED because when they go bad one cannot fix.. I think discounted arguement dependant on skill level. Mostly in general, when a followspot goes bad in it's beyond the skill level of the operator I think to fix in most cases. Often this might be a safety thing in even trying to fix - seen many "Roadie" repairs and bypasses to spots also....
     
  14. ship

    ship Senior Team Emeritus Premium Member

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    Advantage on going LED.
    The tech person might never have to learn how to change a lamp. Given the work load on budding tech people these days - us as it were elders didn't have... do they have time to both learn how to bench focus a Leko, learn DMX address Power in a way we were just 120v back than, and learn both two scene preset and all the various light boards? The S-4 has helped in bench focus if the fixture will do so, still time to learn Leko flagging and focus, stuff like that. The PAR 64 lamp is not completely discontinued, TMB has a Mexico maker for them, but it's gearing up. Will be more expensive and many other PAR lamps are gone. Helps somewhat only in learning the spin the bottle to make a X' on stage from the oval beam, and or in general learning to use the PAR in smaller sizes. etc. etc. My fear is too much tech to learn cat.5 verses cat.6 and fiber verses learning the still use of a fresnel or beam projector or ray light, veses a even last generation moving light. Followspots going LED would be a thing I would be ok with less proper training needed for in focusing on the essentials.
     
  15. DavidJones

    DavidJones Active Member

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    Is anyone making a "big" LED follow spot at this point? All the one I have seen are not a lot brighter than a Tungsten 750-1000w
    Might be okay for high school, and small clubs but for professional shows and long throws, people still want at least a 2k Xenon level output.

    LED are getting close, but all the high output LED moving spots currently on the market sacrifice CRI for output. I'm not too keen on a 70 CRI to follow spot.
     
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  16. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    I just about sole source Robert Juliat, and there 600 watt LED exceeds their 1200 watt HMI, which surpasses anyone else's 1200 watt HMI/MSD. And while a cool no color, very good rendition.

    And silent!
     
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  17. Jay Ashworth

    Jay Ashworth Well-Known Member

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    And clearly, they're pretty proud of them, since I can't find a current-year price to even the nearest kilobuck... :)
     
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  18. theatricalmatt

    theatricalmatt Active Member

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    Another major manufacturer is coming out with a 600W LED followspot, aiming to debut at USITT. Obviously, haven't had a chance for a shoot-out, but I've heard excellent things about it so far.

    Less energy required, cooler for the operator, cooler for the internal mechanics, no color temperature drift, longer 'lamp' life, no need for a separate ballast or igniter -- there's a lot of pluses for very few minuses.
     
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  19. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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    Depending on the exchange rate, $11,000-12,000 each. Very close to the RJ 1200 watt HMI - Super Korrigan - my goto before LED.
     
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  20. Jay Ashworth

    Jay Ashworth Well-Known Member

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    Thanks. Yeah; there are a bunch of other things we need first, like new WX
     

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