Durst TRA450 problem

Discussion in 'Darkroom Equipment' started by himilsbah, Nov 23, 2009.

  1. himilsbah

    himilsbah Member

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    My Durst 1200 with TRA450 stopped working today after a while I saw the smoke.:sad:
    After reassembling the trafo I found one burned resistor.
    Does anybody know the place where could I get electronic diagram of TRA450?
    I consider try to fix it locally and I don't think that will be possible without the diagram.
    Any help gratefully received.

    Bartosz
     
  2. ic-racer

    ic-racer Member

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    Can you make out any markings on the resistor? Did the fuse blow also?
    Check with durst.it, they may be able to supply a wiring diagram.

    I recently found a blown resistor on a Durst CLS head and it was easily replaced:
    [​IMG]
    [​IMG]
    [​IMG]
     
  3. Bob-D659

    Bob-D659 Member

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    Bartosz, if you can post a picture of the inside of your supply showing the burnt part, I'll take the cover off mine and see what the value is, and if there is something else that could go as well.
     
  4. himilsbah

    himilsbah Member

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    Thanks for reply.
    The fuse seems to be fine.
    Bob, clever idea with that mirroring - see following pictures.
    B.
     

    Attached Files:

  5. himilsbah

    himilsbah Member

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    I've just got the TRA450 diagram from Durst.it (thanks guys). :smile:
    If someone interested please write me.
    B.
     
  6. ic-racer

    ic-racer Member

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    So, in my case the resistor blew when I believe the MOV (metal oxide varistor, or surge protector) shunted to ground in order to protect the relay coil during a surge.

    In your case I see a number of things. First, you also are in proximity to a MOV (the black component labled S10K50). So the MOV may have caused to resistor to fail.

    Secondly, both the resistor and MOV are not attached by any means that a commerical manufacturer of electrical equipment would use. All connections need to hold before the solder gets applied. Those components look like they were added later as a modification.

    Can you e-mail me the schematic, I can have a look.
     
  7. Steve Smith

    Steve Smith Subscriber

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    That's what I was thinking. it doesn't look like anything I would want to buy (it does look like something I would make though!).


    Steve.
     
  8. Bob-D659

    Bob-D659 Member

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  9. himilsbah

    himilsbah Member

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    Resistor blew again after replacement.
    Regarding the MOV, I saw it's inconsistent with the diagram but the diagram number I have is:YA 01.174.12, on my board is: YA 01.174.11. Schematic also says CLS 450 Color head instead of mine BWL450.
    confusing...
    Bartosz.
     
  10. ic-racer

    ic-racer Member

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    So, on the schematic the Triac was added around 1977. So, it looks like someone may have upgraded your unit. Perhaps the MOV was added after 1977 but not on any of the schematics that were preserved at Durst.it.

    Check that the MOV is not conducting. Triacs can be checked, but may be easier to just replace it.
    Check for a short in the color head between pins 1,2,3a and 5a. That is a pretty simple schematic. If the transformer is OK you should be able to get the unit working again.
     
  11. ic-racer

    ic-racer Member

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    Also double check input voltage (220v vs 240v). Did the resistor blow right away, or only after triggering the main colorhead bulb. Does the small bulb La1 light up?
     
  12. Bob-D659

    Bob-D659 Member

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    Bartosz, thanks for the pdf's, they just printed.
     
  13. himilsbah

    himilsbah Member

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    THE PROBLEM SOLVED :smile:

    Triac replacing solved the problem. Equivalent for original Triac TAG256/200 (no longer produced???) is Q2015R5.
    I haven't found it in my area but seller suggested BT138-600 as equivalent.
    So far I'v tested short switching series and long exposition as well and it works fine.

    Many thanks for your support
    Bartosz
     
  14. Bob-D659

    Bob-D659 Member

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    Excellent. I was going to suggest replacing it as the only other problem could be the relay in your unit, and that would not burn out the resistor.

    Thanks for the diagrams, my power supply is the 3D version, not many electronic components in it. I will have to clean the relay contacts on the replacement one that is in it, and I will look in my parts bin for a 15 or 20 amp unit. The existing 10 amp one is a bit on the small size for switching for a bulb that draws 10 amps when running.
     
  15. Dave Dawson

    Dave Dawson Member

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    I replaced the relay on my spare psu with a 30A relay!

    Cheers Dave