Durst CLS500 light issue

Discussion in 'Darkroom Equipment' started by Greg Davis, Apr 30, 2013.

  1. Greg Davis

    Greg Davis Member

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    I have a Durst L1200 enlarger with a CLS500 color head with a problem. I noticed the light was very dim when i got it, requiring very long printing times. I looked at the bulb and compared it to what I found recommended in the manuals for the CLS 501 head. My bulb is a 200W, 84V bulb and the manual says a 250W, 24V bulb. So I got a couple of the recommended bulbs. They both immediately blew. It only took a second or less and they were gone. I checked the fuse in the transformer and it is fine. It is a 250V, 5 amp fuse as per the manual.

    I also noticed that all the little bulbs for the filter dials are out, but do not look damaged. I do not see a switch for these or any reference to a switch in the manual. I appreciate any help from those of you that know these enlargers or electrical wiring.
     
  2. ic-racer

    ic-racer Member

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    Which power transformer do you have? TRA 450 in metal box, TRA 500 in plastic box or other? Can you measure that it indeed is putting out 24V?
     
  3. fotch

    fotch Member

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    I would get a manual for the CLS500 color head rather than use the one for the CLS 501 head. Kind of basic troubleshooting.
     
  4. Greg Davis

    Greg Davis Member

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    I will take my voltmeter next time I am at school to see what it puts out, however that won't be for another month. The semester ended yesterday, the same day as my bulbs arrived. It is the plastic case transformer. As for the proper manual, I cannot find one online or in print, but I will keep looking.
     
  5. ic-racer

    ic-racer Member

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    Sometimes a bad socket can cause bulbs to blow if you have a voltage-controlled power supply using a triac. What happens is that a poor connection to the lamp leads to low current flow which causes the regulating feedback loop to open up the triac and put 120V on the bulb. This bridges the poor connection and lights the bulb (with a pop!) before the circuit can regulate it down to 24V.
     
  6. Greg Davis

    Greg Davis Member

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    Well, I tried reading the voltage of this head today. It would jump up to 120V randomly and then settle down for a while, then jump momentarily again. Is there any fix for this? I would love to use this enlarger over the summer. If it is just a bad socket, I should be able to find one somewhere.
     
  7. Greg Davis

    Greg Davis Member

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    Ic-racer, how can I tell if the supply uses a triac? I don't see any arcing evidence on the prongs of the bulb to suspect the socket rather than the supply itself.

    Does anybody have a wiring diagram for the TRA 500? Google doesn't come up with one.
     
  8. Greg Davis

    Greg Davis Member

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    So, this is not a TRA 500, it is an EST 500. I opened it up and saw some damage to the circuit board. It looks like a part fried, and one has even come completely disconnected on one side. The large orange piece is loose and the small blue trimpot is only connected on one end now. Can anyone help me identify and find a replacement for these? I know someone experienced to solder these in place, but I need to get the right pieces for them.
     

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  9. ic-racer

    ic-racer Member

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    Has someone been in there before? That 600V 0.02uF Sprague Orange Drop capacitor is frequently used as a coupling capacitor in tube amps and looks out of place.
    I'd replace all the parts on the blackened part of the circuit board. The one resistor looks like an 8.5K 2W carbon composition but could be replaced with a metal oxide power resistor. The white ceramic resistor looks like a 5W 1.5K which should be easy to find. If the blue trimmer is not totally fried, you could measure the resistance; otherwise check for some other identifying marks.
    mouser.com and allied.com should have the parts needed. If you are compulsive, you could replace all the components and make a like-new circuit board :smile: : http://www.apug.org/forums/viewpost.php?p=767799

    In reality, it would be easier to just locate a new 24V power supply. The power supply I rebuilt also contained all the control functions for the servo motors in a closed loop head; therefore totally irreplaceable.
     
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  10. Greg Davis

    Greg Davis Member

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    I don't know if someone has been in ti before. It was donated to our department. I looked up the resistors at mouser and found a wirewound one that matches the dark one, but there aren't any ceramic resistors that have the same qualities as the ceramic one here. They do have wirewound resistors rated at 5% rather than 10%. Would that work?
     
  11. Greg Davis

    Greg Davis Member

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    And you are right, the big orange one is not from the factory. I certainly don't mind fixing this one, but it would help if someone had a wiring diagram so I knew what was supposed to go there. If anyone has one of these and is willing to take a picture of the inside for me so I can see the correct parts, I may be able to get it going.
     
  12. Greg Davis

    Greg Davis Member

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    So, reading up on other solutions, I came across suggestions of using a Sola power transformer/regulator. My question with that route is how to integrate it into my system. I see that some are rated at a voltage input of 120V and output of 250VA, but are much higher at 120v output instead of the 23.5v that the Durst is. What do I need in addition to solve this? Something like the 88-250 transformer here?
     
    Last edited by a moderator: Jun 11, 2013
  13. ic-racer

    ic-racer Member

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  14. ic-racer

    ic-racer Member

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    I think this is a better replacement for the capacitor. You are not the only one with a problem due to that capacitor. http://www.apug.org/forums/viewpost.php?p=1026302
     
  15. Greg Davis

    Greg Davis Member

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    That power supply is certainly a better price than the one I found. How would something like that be wired to the enlarger and timer?
     
  16. ic-racer

    ic-racer Member

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  17. Greg Davis

    Greg Davis Member

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    It looks like the same circuit board, then. Jensen over at Durst-Pro-USA is helping me find out what parts should be there as well. I think I can get and replace those four components. Hopefully, that is all that is needed. If not, is the power supply you linked to an all in one replacement? Or would I need other components to make it fit the system?
     
  18. ic-racer

    ic-racer Member

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    Depends on what all the original power supply is powering. How many wires come out the back of the original unit? Where do they go?. If it is only powering the bulb it should be all you need. You may also have a fan or additional small dial illumination lamps that would need to be addressed (24V? AC or DC?)
     
  19. Greg Davis

    Greg Davis Member

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    Well, I had a few back-and-forth emails with Jensen at Durst-Pro-USA. Because this is for students, he very generously offered to send a used, but good condition replacement TRA500 at little more than shipping cost. I am still interested in fixing this device, but now it is not as urgent as before. I think I will look at replacing just the board components that are damaged.

    I can't thank Jensen enough for his help getting this up and running. The link you provided for the capacitor is great. Once I get the replacement, I should be able to identify exactly what went in that spot.
     
  20. Greg Davis

    Greg Davis Member

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    The stabilizer arrived today, but it is a European model meant for 220V. They are taking it back to exchange it, but i would still like to fix the old one as a back up. An honest mistake, but they are very generous to help us like this for so little in return.

    To that point, the one ceramic resistor that I need has a tolerance of 10% printed on it, would a 5% tolerance resistor work ok?
     
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  21. ac12

    ac12 Member

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    Yes, smaller tolerance is fine.
    All that means is the actual resistance is +/- 5% from the labeled value, rather than +/- 10%.
    10% tolerance resistors was probably cheaper than 5% tolerance resistors.

    But for wattage/power rating. Do NOT use a resistor with a LOWER wattage rating than what you are replacing. Higher is OK, but NOT LOWER.