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Acer 7257c startup issues....

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    Acer 7257c startup issues....

    I received a bunch of free monitors (LCD & CRT) from a family friend yesterday and the majority of them work fine.
    But there's one monitor which has some weird issue with starting up. It's an Acer 7257c 15" CRT monitor.
    It takes 5-10 minutes for the monitor to start brightening up, colours are shown at the same time, and the colours all look OK at 1024x768 32bit.
    Only problem is that it doesn't get bright enough like other monitors. It's a bit dim when it's "fully bright" and that it takes too long to start up.
    When I received it, the monitor looked like it had been in a very nasty environment.
    There were drip marks of some liquid like oil, the stains were in the rear section on the top of the monitor. There were small amounts of this oil where the vents were, but I opened the monitor up to check it yesterday, the PCB deirectly underneath the section where the vents and oil marks were had no stain marks.... nothing apart from dust.
    I did however take the shell of the monitor out and gave it a good cleaning with cleaning agents + water, because of the dust etc. sticking to the shell. The shell is very clean now. And yes, I did dry the whole shell yesterday + the small piece of foam at the back.... So I can rule out water damage.

    The CRT tube of the monitor is made by Toshiba and the GUI interface of the OSD looks exactly like my Diamaond View/ Mitsubishi one. I found no bad caps on the PCB so I think the caps are still OK.

    But it's very strange because if I turn off the PC and leave the monitor in standby, next time I start it up, it will start instantly, same goes if I turn off the monitor with the power button, but leave it plugged in.
    If I unplug it from the powerpoint for a few hours, it will have issues turning on. If I remember correctly, If I was to unplug it for a minute or two, it will still startup instantly.

    Thanks.
    Last edited by stevo1210; 07-21-2007, 08:25 PM.
    Don't find love, let love find you. That's why its called falling in love, because you don't force yourself to fall, you just fall. - Anonymous

    #2
    Re: Acer 7257c startup issues....

    Originally posted by stevo1210
    Only problem is that it doesn't get bright enough like other monitors. It's a bit dim when it's "fully bright"
    I solved that now, I just got to wait for 15 minutes or so for it to get "fully bright" like other CRTs.
    But when it's "fully bright", the brightness isn't stable, I can see it dimming and brightening very slightly, not a lot, but I can definitely see it and it does get annoying....

    Is the CRT tube starting to die out or is it something else?? The text and images on this CRT look wonderful at 1024x768 24bit colour, 60Hz, but it's a shame that it takes sooooo long to start up and also the dimming and brightening......
    Last edited by stevo1210; 07-21-2007, 08:55 PM.
    Don't find love, let love find you. That's why its called falling in love, because you don't force yourself to fall, you just fall. - Anonymous

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      #3
      Re: Acer 7257c startup issues....

      Check the tube heater voltage. It should be 6,3V usually. Bet your is too low. Trace it to a voltage regulator somewhere on the PCB and check nearby caps. I had similar problem with my Iiyama 17" CRT - there was a cap (100uF IIRC) with high ESR near the regulator's heatsink. It was just bad, no bulging. Replaced it with 330uF and it works fine. Also check for bad solder joints.

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