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Thread: Can I use LED bulbs in my Ilford MG 500 head?

  1. #11
    Eric Woodbury
    Join Date
    Dec 2003
    Posts
    1,637

    Re: Can I use LED bulbs in my Ilford MG 500 head?

    What's wrong with the way it is using halogen type bulbs?

    If it works, don't fix it.

    I don't understand the need to use LEDs, especially white LEDs. Personally, I have built 5 LED light sources for use with 8x10. They are a pain to get them right. Diffusion without attenuation is the worst of it. And cooling. And drift. I only made mine because I've been designing LED drivers for customers (for projection and simulation) for years and decided to make one of my own. They all work fine now, but it has been a long road with many problems. I made a few for friends, but no more. Takes too much time and money.

  2. #12

    Join Date
    Mar 2002
    Location
    The "Live Free or Die" state
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    1,004

    Re: Can I use LED bulbs in my Ilford MG 500 head?

    The RH Designs controllers for that head do use full voltage and vary the duration, one lamp after the other. At least that’s how I remember it. It’s been a while since I set my Ilford head up. I will say from my experience building an LED head with 12 blue and 12 green 3 watt LEDs I have my doubts about the brightness of 2 5 watt panels further attenuated by the dichroic filters. I’m also questioning if the beam angle of those bulbs is going to be the same.

  3. #13
    Drew Wiley
    Join Date
    Sep 2008
    Location
    SF Bay area, CA
    Posts
    18,338

    Re: Can I use LED bulbs in my Ilford MG 500 head?

    Loss of light output is one problem. Another is that any feedback circuit involves miniature matching specific filters also selected in relation to the specified original halogen bulb spectrum. Change that variable, and you'd need a recalibrated or independent feedback loop too, to handle the timing correctly. Plus the angle of incidence issue relative to dichroic filters themselves, which Larry just noted.

    As my mother used to say, you're jumping out of the frying pan and right into the fire instead. Why?

  4. #14

    Join Date
    Oct 2015
    Location
    Nicosia, Cyprus
    Posts
    113

    Re: Can I use LED bulbs in my Ilford MG 500 head?

    So, the answer to my original question seems to be:
    Yes it's safe to replace the ENH with LED… But, it probably won't work as intended…

    Well, only one way to find out I guess…

    Thanks to all who participated, and if/when I try this experiment I'll let you know the results.

    ---
    As a side note regarding the "why"…

    I'm currently using the L1200 for contact printing larger than 4x5" negatives.
    For this purpose, I can continue using the ENH even without the fan, since my exposures are short enough to pose no threat of overheating.

    BUT, when enlarging (and regardless of final exposure), you need to spend some time in focus mode (to frame, and well, to focus), which (with the MG500 system) means that the lamp behind the green dichroic filter gets really hot.

    So, planning ahead, I need to find a working solution to my fan not working properly.

    The idea of switching to LEDs seemed to be the easiest and cheapest… if it works…

    ---
    By the way, in case this info means something to one of you, regarding the possible cause of the fan malfunction:

    During all my printing sessions of the last few days, the fan operates properly for 2 minutes when I turn the power supply on, but thereafter it does nothing… the click on/off sounds emanating from the power supply are there, but the fan does not start…

  5. #15
    Drew Wiley
    Join Date
    Sep 2008
    Location
    SF Bay area, CA
    Posts
    18,338

    Re: Can I use LED bulbs in my Ilford MG 500 head?

    What's the cost of an inline booster fan, pulling the air away from the head, and into an exterior duct? Maybe $75 in this country, unless you need a really quiet one. There must be ample choice in the EU too. It's far less fuss to improvise than what you're contemplating. Seems like you're thinking all this backwards. An inline duct fan can be run entirely separately from your power supply with a simple switch of its own. I've owned several big commercial Durst units requiring far more efficient cooling than the L1200, and in each case opted to run the cooling fan independently of the enlarger light power supply. More reliable that way.

  6. #16

    Join Date
    Feb 2016
    Location
    Netherlands
    Posts
    212

    Re: Can I use LED bulbs in my Ilford MG 500 head?

    Small (and not so small) fans for coolling are utterly standard things for PCs and servers and are widely available. They are also cheap and, even better, reliable. Why build a new light-source and light-management system when you only need to swap a fan?

    12V or 24V fans can be run from standard 'wall-wart' voltage adapters, so your replacement solution can be independent of the Ilford control system. As long as you remember to switch the replacement fans on you will be fine.

  7. #17

    Join Date
    Jan 2013
    Location
    Madisonville, LA
    Posts
    2,412

    Re: Can I use LED bulbs in my Ilford MG 500 head?

    Quote Originally Posted by Thodoris Tzalavras View Post
    For the past fifteen years I've been using 120V, 250W ENH Halogen Lamps like this one:

    Is it possible to replace them with 120V, 5W LED like this one:

    Physical dimensions seem to match.
    I'm mostly concerned about safety.

    --
    If you need additional information regarding the specific MG500 setup I have (there were at least a couple) and/or why I'm considering the switch let me know. Hopefully the answer to my question (either positive or negative) is independent of specifics.
    If the ENH bulbs work for you, I'd keep using them. You can always buy a new fan. No sense to try and re-invent the wheel. L

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