Exposure unit working intermittently

Discussion in 'Platemaking' started by Travis Young, Apr 26, 2020.

  1. Travis Young

    Travis Young Member

    Joined:
    Oct 2019
    Messages:
    58
    Location:
    Victoria Australia
    Hi all,
    I have an old plate exposure unit that has decided to only light up when it feels like it. The worrying part is that it's seems to feel like it less and less.
    It's a Gemini 425 but I'm assuming they would all work in a fairly similar fashion.
    So question one:
    Anyone know what's wrong or had a similar problem?
    Question two:
    Are they cheap and simple to fix?
    You can buy second hand units on eBay for less than $100 so I wouldn't want to spend much on it.

    I'm tipping Chock will let me know what's wrong by the time I wake up tomorrow...........

    Thanks in advance to any and all with input.
     
  2. CHOCK

    CHOCK Senior Member

    Joined:
    Dec 2016
    Messages:
    1,456
    Location:
    Managua,Nicaragua
    Hi;
    Normally, they have a capacitor+ High voltage Transformer, and thyristor electronic components
    look, if they burn, or smell burning, look for loose wires, and finally take a test with the DMM according with the schematic
    2) look for dirty contacts lamp, and burn.
    3)see the timer for dirty contacts, o electronic board if use , and resoldering the board , for dry, cold , solder joint
    4) finally the lamp can be faulty, since they use some gas.maybe is Mercury, or Xenon?
    Blessing
     
  3. Travis Young

    Travis Young Member

    Joined:
    Oct 2019
    Messages:
    58
    Location:
    Victoria Australia
    IMG_20200426_152001598.jpg
     

    Attached Files:

  4. Travis Young

    Travis Young Member

    Joined:
    Oct 2019
    Messages:
    58
    Location:
    Victoria Australia
    Thanks Chock!
    So there doesn't appear to be any burning smell or signs of carbon on any of the electrical components. Wires all seem to be terminated nice and tight.
    Globe looks cloudy and a little bit black.
    When you press the button to expose occasionally the light flickers and now very occasionally it actually stays on.
    I have no idea what sort of globe it is.
     
  5. Travis Young

    Travis Young Member

    Joined:
    Oct 2019
    Messages:
    58
    Location:
    Victoria Australia
  6. CHOCK

    CHOCK Senior Member

    Joined:
    Dec 2016
    Messages:
    1,456
    Location:
    Managua,Nicaragua
    Probably the lamps is faulty. since the extreme is dark, but anyway clean the terminal, by oxide, and exchange the Lamps first
    If the problem continuosly;

    1) the input of the machine is the voltage is 220Vac, , try to call the company for adjust the voltage, if the voltage has 240Vac you can adjust to 220, or similar.

    2) look for the timer in the control panel, as I did indicated you before.

    However remember the transformer can be overheating internal, NOT burning, only that a sometime of working is reheating and try to fail. o.k, since the Varnish inside is deteriored.

    Blessing
     
  7. CHOCK

    CHOCK Senior Member

    Joined:
    Dec 2016
    Messages:
    1,456
    Location:
    Managua,Nicaragua
    Lamp is faulty, and replace lamp+ contacts too.
    Test the timer in the control panel , whatever if mechanical or Digital, very Important as I did mention before
    Blessing
     
  8. Travis Young

    Travis Young Member

    Joined:
    Oct 2019
    Messages:
    58
    Location:
    Victoria Australia
    Any idea what sort of lamp that is?
    Timer is mechanical. Visually looks fine. Little green circut breaker cuts in and out with the timer no problems.
    Thank you for holding my hand through some very basic diagnostics.
    If you ever come to Australia dinner is on me!
     
  9. CHOCK

    CHOCK Senior Member

    Joined:
    Dec 2016
    Messages:
    1,456
    Location:
    Managua,Nicaragua
    possible tungsteno, you can reach the in Germany, or USA, i know some place

    with the number of lamp printed, is enough

    Do not worry, thank you my friend

    take care with Covid-19

    Blessing
     
  10. Travis Young

    Travis Young Member

    Joined:
    Oct 2019
    Messages:
    58
    Location:
    Victoria Australia
  11. Travis Young

    Travis Young Member

    Joined:
    Oct 2019
    Messages:
    58
    Location:
    Victoria Australia
    Thanks mate
     
  12. CHOCK

    CHOCK Senior Member

    Joined:
    Dec 2016
    Messages:
    1,456
    Location:
    Managua,Nicaragua
    ok ,

    let me know

    test
     
  13. Travis Young

    Travis Young Member

    Joined:
    Oct 2019
    Messages:
    58
    Location:
    Victoria Australia
    Hi Chock,
    Lamp replaced, contacts cleaned, now 100% operational. Made 8 plates in the last few days and never missed a beat.
    Many thanks.
     

  14. CHOCK

    CHOCK Senior Member

    Joined:
    Dec 2016
    Messages:
    1,456
    Location:
    Managua,Nicaragua
    Thank you sir

    Blessing
     
Loading...