3 pin scanner inverter

Discussion in 'General Electronics Chat' started by klayus, Nov 19, 2014.

  1. klayus

    Thread Starter New Member

    Jul 15, 2010
    4
    0
    Can anyone help me? I've taken apart a konica copier machine and i salvaged among other things this lamp with its inverter.
    the problem is the inverter has 3 pins on the input. by following the traces to the capacitor i've found which one is the + and the ground but i cant figure out whats the 3rd (middle) pin and the lamp dosen't start! it dosent draw any current either.
    i gave it 15V on the + and middle pin, i even put the middle pin to ground, but nothing happens.
    i didnt try giving it the full 24V as all of my other scanner light inverters start with less than their full voltage.
    here are some pics:
    [​IMG]
    [​IMG]
    please help [​IMG]
    i tried bypassing the fuse, dosent work.
    The ic is a 10393 comparator so i'm guessing there should be some voltage on that pin to maybe set the intensity of the light.

    thanks in advance
     
  2. pwdixon

    Member

    Oct 11, 2012
    488
    56
    Perhaps this not working is why the thing was in the bin in the first place?
     
  3. klayus

    Thread Starter New Member

    Jul 15, 2010
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    it wasn't in the bin, it was decommissioned because of a mechanical issue, besides I have a similar one, the inverter differs a bit, both of them have 3 pins on the input and I cant start either one of it
     
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
    5,801
    1,105
    The top of the board is marked "T1.25A 125/250V". That indicates a mains-voltage-rated slow-blow fuse, suggesting the module is intended to run from mains voltage? On the other hand, the trace clearances around the input connector pins look inadequate for mains voltage. Can you tell us what the voltage rating of the electrolytic capacitor is?
     
  5. debe

    Well-Known Member

    Sep 21, 2010
    947
    184
    Ive wrecked a lot of Photocopiers & there main voltage inside is 24Vdc. The earlier inverter module for the scan lamps used a linear voltage on the 3rd wire to control lamp brightnes. The later ones I couldn't get to work either, I suspect the control signal is some digital signal.
     
  6. klayus

    Thread Starter New Member

    Jul 15, 2010
    4
    0
    i dont think that we're talking about a digital signal here as this inverter only has a comparator on it (10393 IC). perhaps it requires a negative voltage? is there no one out here who has a similar copier that can test what happens on that pin???
     
  7. klayus

    Thread Starter New Member

    Jul 15, 2010
    4
    0
    I got it working, the middle pin has to be put to ground through a limiting resistor after the circuit starts.
    [​IMG]
     
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