XEROX XM7-24w problem

Discussion in 'General Electronics Chat' started by Mihael Lalić, Jun 13, 2015.

  1. Mihael Lalić

    Thread Starter New Member

    Jun 13, 2015
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    Hello everyone,

    I have a problem with my Xerox XM7-24w monitor. I turn it on and it works perfectly, and monitor buttons (MENU, DOWN, UP, AUTO, POWER BUTTON) work fine, and then, I don't know why, suddenly, it turns itself off. Now, there are two scenarios. First, if I am fast enough and manage to press AUTO button it turns itself on and autocorrects picture, and it works ok but any button I press (monitor buttons) turn monitor off. Second scenario is if I am not fast enough - It remains turned off and I can't turn it on for a while. I tried to plug it in another laptop but nothing, and my cable works fine. After a while it suddenly turns itself on...

    Please help. Thank you in advance
     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Welcome to AAC!
    The first things I'd check would be the power supply voltages, electrolytic capacitor condition, and any plug/socket connections.
    Can you provide a link to a service manual or schematic for the monitor?
     
  3. Mihael Lalić

    Thread Starter New Member

    Jun 13, 2015
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    Thank you.
    I must say that I am not really capable to disassemble monitor. And even if I manage to do that, i can't be sure if anything doesn't work. Sorry.
    http://www.manualmonitor.com/xerox-xm7-24w
     
  4. ian field

    Distinguished Member

    Oct 27, 2012
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    Couple of years back I scrounged a "broken" flat monitor that was actually intermittent, sometimes the brightness and contrast turn themselves down and in humid weather it sometimes turns itself rapidly on and off.

    Right from the start I suspected a drink had been spilled down the front and contaminated the buttons, I took the buttons PCB out and remade the button solder joints hoping it would dry them out - unfortunately it looks like replacement buttons is the only cure.

    As someone else mentioned; flaky operation can be failing electrolytics in the PSU. They usually get hot as they fail and boil the electrolyte - the pressure often bulges the top of the aluminium can. A quick look to see whether that's the case usually isn't THAT much dismantling.

    In the UK, most of the consumer electronics component supply houses offer capacitor replacement kits for the most popular TVs - but I've never heard about whether the same service exists for monitors.
     
  5. Mihael Lalić

    Thread Starter New Member

    Jun 13, 2015
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    Thank you for your answer .
    I'll take a closer look at these buttons, they are suspicious...maybe solder is broken or something. That is the best i can do. If that doesn't help, i'll take it to servis. Thank you :)
     
  6. ian field

    Distinguished Member

    Oct 27, 2012
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    Solder is a possibility - not only Europe uses dodgy RoHS solder - anywhere that wants to export to Europe has to as well.

    A good illuminated magnifier is a must have, first for finding any dodgy looking solder joints - then again if you feel brave enough to try reworking the solder on all those fine pitch ICs.
     
  7. Mihael Lalić

    Thread Starter New Member

    Jun 13, 2015
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    Can it anyhow be PC's fault? Because buttons work normaly untill shut down happens. After that problem appears...

    I can normaly press AUTO button when it turns itself off....and that button works fine, after that they all shut monitor down, and after a few seconds they just don't respond
     
  8. ian field

    Distinguished Member

    Oct 27, 2012
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    Most of the more recent versions of Windows have power management that can put the monitor into standby, but they mostly only switch it back on if you move the mouse or press a key. Never heard of power management actions going intermittent - but I suppose its possible.
     
  9. Mihael Lalić

    Thread Starter New Member

    Jun 13, 2015
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    Nah, it happens in the middle of a game...that can't be it.

    And interesting thing is that it happens only once, in first 10-15 minutes , after that it works normaly whole day
     
  10. ian field

    Distinguished Member

    Oct 27, 2012
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    Failing electrolytics usually develop high internal resistance (ESR), they get hot in normal use when that happens, and the ESR situation improves slightly as temperature increases.

    Serviceing reports from when I was in the TV trade sometimes described a set top box that had worked OK for years, then the householder unplugged everything to go on holiday. When everything was plugged back in, things of the type like set top boxes could go bang or just not start up. All the time it was plugged in, those tired old electrolytics were kept at working temperature, when they were left to cool the ESR rises to it true value, its hard to predict what which capacitor will do what to a PSU when it goes bad - but it sometimes isn't pretty!

    ATM: I'm still struggling to recover data on the drives in my other PC after an electro went bad in the PSU.

    Often I hear people describe that their PC needed an increasing number of pressing the PWR button before it'd start - then one day it started with a bang!

    The situation can seem to improve as it warms up - but it could be lulling you into a false sense of security!
     
  11. Mihael Lalić

    Thread Starter New Member

    Jun 13, 2015
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    Just great :D well, I guess I'll be sitting a little further than usual.
    Thank you for your time and effort :)
     
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