Problem with ORIEL Xenon Lamp power supply

Discussion in 'Power Electronics' started by Andrea Antonello, Feb 15, 2018.

  1. Andrea Antonello

    Thread Starter New Member

    Feb 15, 2018
    8
    2
    Hi everyone!
    I'm using a power supply (mod. Oriel 68907) in my lab to power a 500W Xenon lamp for a solar simulator, but the power supply wasn't turning on yesterday (display off, fan off, etc.). I asked the manufacturer but since this is an old part (1999), they don't have support available and even not a schematic. What I was able to obtain was the pcb traces and the components mask (although the right part of the board is different since it appears to be a different board revision). I tried to match the info I have the best I could with Inkscape in order to try debugging this thing.
    What I noticed is that there are 4 test points on top of this board, and only T1 reads what's expected, 12V. T2, T3, T4 all read zero (they are highlighted in blue in the attached picture to this thread).
    Also, if I excite the VN10KLS transistor in the green circle (i.e. I check the continuity between ground and gate, thus supplying a small current input to the transistor), then the fan starts and the display switches on, and everything seems to work fine. When I remove the probe, everything blacks out again.
    Do you have any idea of what could be wrong and what steps could I take to debug this?
    I'm attaching the partial schematic I was able to obtain and the voltage measurements I took with respect to ground. The wall input comes, after the ON/OFF equipment switch, from the molex in the bottom left of the schem

    [​IMG]
    [​IMG]
    [​IMG]
     
  2. Andrea Antonello

    Thread Starter New Member

    Feb 15, 2018
    8
    2
    Here's a more complete layout
    [​IMG]
     
  3. ericgibbs

    Moderator

    Jan 29, 2010
    6,210
    1,178
    hi Andrea,
    Welcome to AAC.
    Is there a label on the Fan stating its operating voltage.?
    E
     
  4. InPhase277

    New Member

    Feb 15, 2018
    23
    0
    Start going backwards from the the transistor that seems to make everything work. There is an optoisolator, ISO1, that seems to switch that transistor. ISO1 itself is fed from whatever K1 is.
     
  5. Andrea Antonello

    Thread Starter New Member

    Feb 15, 2018
    8
    2
    Thanks for the greetings! :) Hope to learn something new in this forum... Anyways, i'm currently not in the lab now, I'll check first thing in the morning tomorrow
     
  6. Andrea Antonello

    Thread Starter New Member

    Feb 15, 2018
    8
    2
    So, K1 is a relay. I'll check tomorrow morning for the model
     
  7. ericgibbs

    Moderator

    Jan 29, 2010
    6,210
    1,178
    hi Andrea,
    The reason for asking the Fan voltage is, that if it mains rated and it does not run, it maybe a problem in the mains input side, fuses etc.
    E
     
  8. Andrea Antonello

    Thread Starter New Member

    Feb 15, 2018
    8
    2
    Oh I see. If it can be of any help, we checked for continuity the two fuses on the bottom left of the schematics and another fuse on the Xenon supply voltage board and they look fine
     
  9. Andrea Antonello

    Thread Starter New Member

    Feb 15, 2018
    8
    2
    My lab mate checked the fan. It is supposed to run at 12V
     
  10. ericgibbs

    Moderator

    Jan 29, 2010
    6,210
    1,178
    hi,
    OK, it was worth checking that out.
    E

    EDIT:
    Searched the web for a circuit diagram, no luck.
     
    Last edited: Feb 15, 2018
  11. Andrea Antonello

    Thread Starter New Member

    Feb 15, 2018
    8
    2
    Guys, I solved the problem. Turns out that the lamp housing has a protection plate that functions as an interlock. Surprisingly, if you remove that plate, the controller doesn't turn on, not even the fan or the display. That was quite a surprise after two days of troubleshooting...
     
    IamJatinah and InPhase277 like this.
  12. ericgibbs

    Moderator

    Jan 29, 2010
    6,210
    1,178
    hi A,
    Thanks for letting us know its OK.:)
    E
     
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