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Dynaspot and the DTA lamp

Discussion in 'Lighting and Electrics' started by church, May 22, 2008.

  1. church

    church Active Member

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    I recently was asked to repair a Dyna Spot that was owned by a school from new - getting hot and the light output was low. The spot had recently had a 1500W DTA lamp installed - listed as the alternative to the DTJ 1500W incandescant lamp in the Altman literature. they wanted to save lamp cost by using the 100 hr halogen lamp.

    When I removed the cover and inspected the unit I was surprised to notice that the filament position was too low - by 3/4 of an inch. The top of the filament support frame is actually on the optical axis. I checked the lamp holder mounting and it has not been changed. I swapped in a DTJ lamp and the filamment centre is correctly located on the optical axis. I checked the specs for the lamps and they should indeed be a direct fit for either type. The only clue I found was a picture of an Osram lamp on the internet that suggests that the Osram DTA may be a longer lamp.

    So possible explanations include: the Ushio lamp in this fixture is not really a DTA lamp; or there has been a design change in the DTA lamp that is not reflected into the lamp specs; or (which seems unlikely) the DTA lamp was incorrectly specified for this fixture due to a lamp spec error; or there is some other explanation that someone else is aware of. Any ideas or suggestions.

    I can easily fix this by making and installing a spacer under the Mogul Prefocus lampholder. Of course this explains why this follow spot was getting hot and not producing much light output.
     
  2. JD

    JD Well-Known Member

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    One of the key elements of a lamp specification is the LCL or Light Center Length. Any lamp made to specification should have the same LCL.

    Definition: "The distance between the center of the filament, or arc tube, and a reference plane - usually the bottom of the lamp base."

    The fact that you can find two different versions of the same lamp from different manufacturers that differ in LCL means someone is not following the rules! You mentioned that the Osram lamp is a different length, but is the LCL truly different? I highly doubt that the specs have changed on the DTA. It is more likely that it was an oversight in the manual. It is not impossible that the "DTA" in the fixture is not really a DTA. It is also not impossible that a lamp manufacturer is playing fast and loose with their products. I have run into this with variances in DYS lamps.

    EDIT: I checked and both the DTA and DTJ have a LCL of 3.437 or 87.3mm Something funky with the lamp that is in there. Should have worked.
     
    Last edited: May 22, 2008
  3. icewolf08

    icewolf08 CBMod CB Mods

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    As JD said, the two lamps have the same LCL, so it should work. The DTJ is a bigger and longer lamp, but that shouldn't matter if the LCL is the same. It is possible that you have a bench focus issue. If the reflector is designed to fit a DTJ which is a T20 lamp (2.5" diameter) and you put a DTA in which is a T8 (1" Diameter) you have the potential for less efficiency from the reflector, or at least the need to check the bench focus on the unit.
     
  4. JD

    JD Well-Known Member

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    Try laying the DTA on a table next to a known good lamp and see if the center of the filament is the same distance to the base flange. From what you said about a 3/4 inch error, I would suspect not. Might just be a funky lamp.
     
  5. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    Whether a T8 or a T20, the relationship between filament and reflector does not change.

    A Dyna-Spot still in service? That's great. Probably fine for the times the theatre needs it.
     
  6. derekleffew

    derekleffew Resident Curmudgeon Senior Team Premium Member

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    I have to laugh that there's actual Lux colors designated for the colored boomerang handles. I never knew that before.

    Frame 0=Blackout/Douser
    Frame 1=R26 Red
    Frame 2=R89 Grn
    Frame 3=R67 Blu
    Frame 4=R52 Lav
    Frame 5=R12 Straw
    Frame 6=R31 Pnk

    Sure, I'd use those colors, just so they match the handles. Who needs L205, L223, and R05?
     
  7. Lightingguy32

    Lightingguy32 Active Member

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    Derek,
    Our school still has 2 (if not mistaken 3) Dyna spots or similar model altman spotlights. Is there any precaution to take with them since they all have asbestos insulation on the wiring? They are due for replacement next year, so if any one wants one of them, call me up and I can arrange for you to take it.
     
  8. gafftapegreenia

    gafftapegreenia CBMod CB Mods

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    There is an all-girls highschool in my area that has two carbon arc Super Troupers. The old TD there knows how to use 'em, too!
     
  9. JD

    JD Well-Known Member

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    Wow! So many things to say, and none of them proper :)
    Sounds like such a heavenly combo for an old light guy! Oh well, we can all dream about when we were younger. (Where were these things when I was young ??)
     
  10. ship

    ship Senior Team Emeritus Premium Member

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    Just checked the specs on the lamps also, should all be the same and match up. GE, Osram, Ushio, Phillips, Fuji and possibly Eiko either make or used to make them all or any number of them still make the lamp in not having updated my notes recently. One thing the ANSI code does is ensure LCL is the same or within about a millimeter of the same though output, lamp life and color temperature amongst other things such as filament type can vary to some extent brand to brand. Either you have something unusual - given without changing the bench focus and both lamps were properly seated there was this difference or as said, the lamp removed was not a DTA. On the other hand, other than a 250w/24v #6860C, I'm not familiar with any mog prefocus lamp that is 3/4" shorter in LCL. The above 44.5mm LCL lamp short of a transformer will have blown up instantly but been really bright while it lasted. This or a Radium RKP 500w/24/KV/P40S at 24v/500w also will have blown but is 66mm in LCL both doubtful especially since the former is a G-80 globe and the latter is a T-112mm tube with top mirror.

    Everything else on the market either has a LCL of 100mm such as a BVT or CWZ, or is the 87.3mm. Is it possible you have one of these or a BVW at 100mm you were comparing the DTA lamp to and in using this new lamp they thru the bench focus way out of wack to compensate? The CWZ is a 300 to 350hour lamp and someone might have thought that even better yet, otherwise the BVW is still on the market but at 2KW will have been really hot but dim if out of focus.

    Interesting.... certainly if marked as a DTA and it's LCL is off the manufacturer would take it back even if used. Challenge will be finding the recipt for the lamp or hoping your lamp distributer has an in with the manufacturer in doing the exchange.

    DTJ G.E. #30004 (?disc.) 39/CL, Incd. 1.5 Kw T-20 c-13D LCL 3.7/16" Mog. Pf Base Down ±30̊ 3,225̊K 42,500 Lum 25DTJ Philips #31744-6 CL, Incd. 1.5 Kw T-20 c-13D LCL 87.3mm P-40s Base Down 3,225̊K 42,500 Lum 25
    DTJ Ushio #1000221 CL, Incd. 1.5 Kw T-64mm c-13D LCL 87.3mm P-40s Base Down 3,200̊K 42,500 Lum 25
    DTJ Fuji CL, Incd. 1.5 Kw T-20 P-40s


    DPW G.E. #29964 (?disc.) CL, Incd. (HRG) 1 Kw T-20 c-13 LCL 3.7/16" Mog Pf Base Down ±30̊ 3,200̊K 28,000 Lum 50
    DPW Ushio #1000214 (JCS120v-1000w) CL, Quartz 1 Kw T-64mm c-13 LCL 87.3mm P-40s Base Down 3,200̊K 28,000 Lum 50

    DTJ G.E. #30004 (?disc.) 39/CL, Incd. 1.5 Kw T-20 c-13D LCL 3.7/16" Mog. Pf Base Down ±30̊ 3,225̊K 42,500 Lum 25
    DTJ Philips #31744-6 CL, Incd. 1.5 Kw T-20 c-13D LCL 87.3mm P-40s Base Down 3,225̊K 42,500 Lum 25
    DTJ Ushio #1000221 CL, Incd. 1.5 Kw T-64mm c-13D LCL 87.3mm P-40s Base Down 3,200̊K 42,500 Lum 25
    DTJ Fuji CL, Incd. 1.5 Kw T-20 P-40s

    DPW G.E. #29964 (?disc.) CL, Incd. (HRG) 1 Kw T-20 c-13 LCL 3.7/16" Mog Pf Base Down ±30̊ 3,200̊K 28,000 Lum 50
    DPW Ushio #1000214 (JCS120v-1000w) CL, Quartz 1 Kw T-64mm c-13 LCL 87.3mm P-40s Base Down 3,200̊K 28,000 Lum 50
    DTA G.E. #X16464 (?disc.) (Disc.) 4/CL, Quartz 1.5 Kw T-8 c-13D LCL 3.7/16" Mog Pf Base Down to Horz 3,200̊K 39,000 Lum 100
    DTA G.E. #30522 4L, Quartz 1.5 Kw T-8 c-13D LCL 3.7/16" P-40s (Base Down to Horz) 3,200̊K 41,000 Lum 300
    DTA Osram/Sylvania #54716 CL, Quartz 1.5 Kw T-8 LCL 87.3mm Mog Pf Any Burn Pos. 3,200̊K 39,000 Lum 100
    DTA Ushio #1000220 (JCS120v-1500wCP40) CL, Quartz 1.5 Kw T-25mm c-13D LCL 87.3mm P-40s/42 Base Down 3,200̊K 39,000 Lum 100
     
  11. ship

    ship Senior Team Emeritus Premium Member

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    Asbestos has to go but you should not be removing it. Wires leading to the fan are also probably rotton. Sorry but I would have to upgrade it for pay as would other pro's at doing such a thing and there will be a lot of work to do on it. Removing asbestos wiring and or higher amperage wiring is not something to be doing without a good deal of experience and training. No offense ment but in doing it properly it should be done by those trained to do it. I would recommend you send the thing out for re-wiring and interview those that would do it for you very well by way of experience or as it were how close do they sound like "Ship" in considering how they do things, (as it were if useful though not something as a term I would have thought of,) in how they would go about it in determining if they would do it properly or not. Are they talking about stuff like TGGT wire or just SF-2 which could be fine also, are they talking high temp. terminals and fiberglass tape or just kind of wiring it like a Leko and or sound very vauge? If sales person talking to you, ask to talk with the tech person that will be doing the repair and sound that person out for knowing what the heck he or she is doing by way of not just confusing you but also if doing so being able to slow down and explain what details of the process you don't understand fully in getting the lingo used at times from a true tech person jumping from part to part, step to step. Those that know can also explain in detail.

    AT one point in a salvage shop I ran across an Altman 1000 with a Bryant 20 Amp twist lock plug/connector inside the body between lamp socket and switch. Really was one of their white twist lock nylon plugs inside the fixture itself - I was amazed but broke at the time plus it had a cracked lens I could not hope to afford at the time replacing. No idea of why such a plug was there but even early in my career I knew something was very wrong here with how it was cared for as it were. None the less, there is all kinds of tech people out there no matter their age or experience. Some will do factory spec or better, others will "fix it." I would say TGGT wire in replacing the asbestos in that while it won't get that hot especially for a 1.5Kw fixture, the TGGT will do a better job than SF-2 should say the fan go out or it not being as efficient in cooling at the lamp socket. On the other hand, I wouldn't use TGGT for the cord whip give it has less stranding thus is less flexible especially in the long run of use.

    This much less a 90C SOOW cable as long as in good shape would normally be fine for the cord whip but would not touch SEOW cable or even the Euro versions of the SOOW. Details like that or inspecting the lamp socket properly and being able to either re-surface it or replace it are needed to be looked at etc. At very least for the re-wiring proper training and qualification at times even beyond what Altman themselves will be able to do but at least what they would be able to do in servicing the fixture will be necessary. Other follow spot manufacturers such as Lycian might also be willing to re-wire it. Such companies that are factory as an option could also properly bench focus the thing much better than some average DJ shop unless of course as above the tech person there is really good.

    Very interesing the gel types - My Kliegl Dyna Beam has the same colors on it's boomerang levers.

    Speaking of that, check the search option of this forum on "Kliegl Dyna Beam" - believe I posted a large post about the upgrade to my own at least... believe it's a 45 year old follow spot with still working 3Kw incandescent lamp. Might be able to get some ideas if I went into enough detail, otherwise if as similar as I think they are to the Kliegl, short of checking the specs, than I would know a lot about them, much less its only been a few months since I re-wired and totally re-did my own fixture.
     
    Last edited: May 23, 2008

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