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Thread: Change led bulb for enlarger

  1. #1

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    Change led bulb for enlarger

    Hello,

    I want to change the old light bulb to a new one for my Omega D5500. It is Omega 200W 82V, originally. I found some on ebay. But, is it better if I use a GE 300W 82V, instead? What's the matter with my enlarger, its head? I just think that more power is faster exposure. I'm wrong?

    Please share your idea!
    Truong

  2. #2
    ic-racer's Avatar
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    Re: Change led bulb for enlarger

    It is not better to use the wrong bulb with that enlarger EYA, EYA, EYA... its a pretty common, inexpensive bulb! Are you having trouble finding one?

  3. #3

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    Re: Change led bulb for enlarger

    Oh no, I just wonder how fast is does or save the printing time if I use a more power bulb.

  4. #4
    8x10, 5x7, 4x5, et al Leigh's Avatar
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    Exclamation Re: Change led bulb for enlarger

    Quote Originally Posted by kissssss View Post
    Oh no, I just wonder how fast is does or save the printing time if I use a more power bulb.
    50% more power = 50% more heat in the head.

    If the head has heat-absorbing glass, it might shatter.

    You could damage the head, or the negatives.

    - Leigh

  5. #5

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    Re: Change led bulb for enlarger

    Thanks, Leigh. I don't know head's structure, so I should find a right one ...

  6. #6
    ic-racer's Avatar
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    Re: Change led bulb for enlarger

    The power supply in the D5500 measures the voltage across the lamp filament and keeps it exactly at 82V. I'm not sure how the added current of a larger wattage lamp will affect the components, but, unless you have a spare D5500 power supply to play with, I'd not chance it

  7. #7
    8x10, 5x7, 4x5, et al Leigh's Avatar
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    Exclamation Re: Change led bulb for enlarger

    Quote Originally Posted by ic-racer View Post
    The power supply in the D5500 measures the voltage across the lamp filament and keeps it exactly at 82V. I'm not sure how the added current of a larger wattage lamp will affect the components...
    Most constant-voltage supplies are current limited, to prevent blowing the supply in case of a fault.

    Assuming this one is, the higher current would result in the output voltage dropping below the nominal 82 volts, probably by a substantial amount, which would completely defeat the regulation of the light output.

    If the supply is not current-limited, a 50% overload would probably blow it.

    - Leigh

  8. #8
    ic-racer's Avatar
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    Re: Change led bulb for enlarger

    Many of the regulated enlarger power supplies I am familiar with are Triac or SCR based and that component would be the limiting factor for the bulb wattage it can handle. On thinking it over again, I could imaging that an uprated Triac may allow the higher wattage bulb to work, as the only thing between the mains and the bulb is the Triac. The $12 true-RMS converter and other sensitive components are pretty much isolated from the high voltage circuit by an optoelectric connection.

    But, of course everything from the bulb socket to the cooling system will be stressed at the higher wattage and I'd certainly not recommend it.

    In ten years of using the system, I can't say I have ever wanted more power from it as long as I had the correct mixing box for the job.

  9. #9
    8x10, 5x7, 4x5, et al Leigh's Avatar
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    Re: Change led bulb for enlarger

    But the triac is (should be) mounted on a heatsink. Increasing its dissipation by 50% would require a larger heatsink, else the device would overheat.

    Considering that a 50% increase in bulb power is only about a 1/2-stop decrease in exposure time, it's hardly worth any effort.

    IM[-H]O there are too many inter-related problems to even consider uprating the bulb.

    - Leigh

  10. #10
    ic-racer's Avatar
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    Re: Change led bulb for enlarger

    Quote Originally Posted by Leigh View Post
    But the triac is (should be) mounted on a heatsink. Increasing its dissipation by 50% would require a larger heatsink, else the device would overheat.

    Considering that a 50% increase in bulb power is only about a 1/2-stop decrease in exposure time, it's hardly worth any effort.

    IM[-H]O there are too many inter-related problems to even consider uprating the bulb.

    - Leigh
    Agree!

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