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Thread: Electronic circuit in D5 lens turret

  1. #11

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    Re: Electronic circuit in D5 lens turret

    Here's what the underside looks like. Still a puzzle to me.

    Click image for larger version. 

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  2. #12

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    Re: Electronic circuit in D5 lens turret

    Quote Originally Posted by HMG View Post
    Here's what the underside looks like. Still a puzzle to me.

    Click image for larger version. 

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    I think that this was used as a package printer and that board connected to a roll paper holder and controlled paper advance.

  3. #13

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    Re: Electronic circuit in D5 lens turret

    That could be. But why all the sensors around the lens opening? One would be enough to signal the end of exposure.

  4. #14

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    Re: Electronic circuit in D5 lens turret

    i still dont see the sensors but i do see diode symbols at each of the 9 contact points in that spaghetti etching so each is polarized. each of the 9 contacts also has 2 connections. 9 photo diodes looking down at the easel?

    ok so hook up a vom n trace them out using light and see if you get any resistance change?


    interesting! gotta be from some sort of an automatic system.

  5. #15

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    Re: Electronic circuit in D5 lens turret

    Quote Originally Posted by Paul Ron View Post
    i still dont see the sensors but i do see diode symbols at each of the 9 contact points in that spaghetti etching so each is polarized. each of the 9 contacts also has 2 connections. 9 photo diodes looking down at the easel?
    ok so hook up a vom n trace them out using light and see if you get any resistance change?
    interesting! gotta be from some sort of an automatic system.

    EE son tells me the symbols might indicate direction of current flow, rather than an actual diode. Since this is likely for DC, might make sense. This was mounted around the lens opening in the lens turret, facing up toward the light source. So it must be measuring some characteristic of the light.

  6. #16

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    Re: Electronic circuit in D5 lens turret

    yes that would be directional current flow and the diode electronic symbol would be indicative some sort of diode there.

    i dont see any sensors looking up, i only see 2 solder connections at each symbol. the sensors are more likely facing down at the easel .

    interesting gizmo for an enlarger.

    i hope someone can ID it?

  7. #17

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    Re: Electronic circuit in D5 lens turret

    Quote Originally Posted by Paul Ron View Post
    yes that would be directional current flow and the diode electronic symbol would be indicative some sort of diode there.

    i dont see any sensors looking up, i only see 2 solder connections at each symbol. the sensors are more likely facing down at the easel .

    interesting gizmo for an enlarger.

    i hope someone can ID it?
    This was mounted on the upper side of the lensboard. The sensors (if they are sensors) are facing up - toward the light source - not down toward the easel. This photo is with the lens turret removed, looking down through the lens in the same direction as the light from the head.

    Click image for larger version. 

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  8. #18
    Bill
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    Re: Electronic circuit in D5 lens turret

    I have heard mentions (I think in Ansel Adam's The Print) of light sensors being used as feedback to keep the light intensity of a cold head constant. If those diode symbols indicated photodiodes, this device could be for that purpose.

  9. #19

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    Re: Electronic circuit in D5 lens turret

    Quote Originally Posted by Bill Rolph View Post
    I have heard mentions (I think in Ansel Adam's The Print) of light sensors being used as feedback to keep the light intensity of a cold head constant. If those diode symbols indicated photodiodes, this device could be for that purpose.
    This is how many low voltage enlarger lamps are stabilized also.

  10. #20
    Tin Can's Avatar
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    Re: Electronic circuit in D5 lens turret

    and some high voltage cold lamps were stabilized by thermistor and heaters

    sometimes very complicated circuits
    2022

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