Circuit problem with custom made camera

Discussion in 'General Electronics Chat' started by dompote, Nov 20, 2015.

  1. dompote

    Thread Starter New Member

    Nov 20, 2015
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    Hi. I am hoping somebody may be able to help me out with this. I have a custom-made camera which somebody made for me some year back. Unfortunately I am unable to trace the engineer I commissioned to make it for me so I can't go back to him. There seems to be a problem with the circuit. Please see attached photo and diagram. It seemed that the sliding on/off switch was faulty as when I turn it on it no longer stays on, but goes on and off, depending on how I wiggle the switch. So my idea was to replace this switch. But when I looked at it in detail, I noticed that when I remove the ethernet cable from the ethernet port (top right corner) the switch works fine. I can tell this as there is a buzzer to tell me when the power is on or off. The ethernet port is used for a connection to a motor (not shown) on the camera. An ethernet cable is simply inserted into this port and the power is then supplied to the motor which is in a separate unit. The only thing I can think of is that there is a reset button on the circuit (I think this is the 'wire link' on the left-hand circuit diagram) which is used when I insert a new film in the camera. This button does the same as turning the unit off and on. I recall the maker of this telling me that I can use this button to reset or simply turn the unit off and on again. I just wonder if this reset button could be the cause. I'm sorry I can't be too technical about this...I'm just hoping there may be a way to solve this. Any advice is much appreciated. Many thanks, Dominic

    cam-circuit.jpg cam-cir-diagram.jpg
     
  2. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Does the camera work ok without the motor attached,if so could be the motor is jammed,or switch dirty,
    Short out the switch terminals with a screwdriver.
     
    Last edited: Nov 20, 2015
  3. alfacliff

    Well-Known Member

    Dec 13, 2013
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    sthe motor uses current thats going through the switch. there is probably a low resistance fault in the switch.
     
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  4. dompote

    Thread Starter New Member

    Nov 20, 2015
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    I should clarify, this is a camera control unit rather than a camera in itself. This unit is used to control a motor which rolls film through a camera at varying speeds.
    So, if it is a low resistance fault, this would simply be case of replacing the sliding switch? Would be great if it's that simple!
    Maybe I should try this first.
     
  5. paulktreg

    Distinguished Member

    Jun 2, 2008
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    Switch it on and short out the two pins adjacent to the black switch slider with a crocodile clip or screw driver.

    Does it work properly?
     
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  6. dompote

    Thread Starter New Member

    Nov 20, 2015
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    There are three pins adjacent to the switch slider - so do I ignore the middle one? Thanks.
     
  7. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Short the outer two together,see if it will work better.
     
  8. dompote

    Thread Starter New Member

    Nov 20, 2015
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    YES! When I short it out with the two outer prongs connected, it works fine! So, what is the cause, the switch?
    Many thanks...
     
  9. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    Yes its the switch...
     
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  10. dompote

    Thread Starter New Member

    Nov 20, 2015
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    thank you all so much for your help. This seems to be the solution to my problem
     
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