Dell E176FPf power cycles after being on several minutes

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • sceva
    Senior Member
    • Feb 2010
    • 196

    #1

    Dell E176FPf power cycles after being on several minutes

    This monitor will come on, work well for 15 minutes to a couple of hours, then the display will flash on/off about once a second. It shows "Dell" on the screen when it is in the on cycle, not the computer image that was being displayed before the cycle began. The power led also flashes on/off with the display, and the power button has no effect. It will continue to flash until I remove the power cord. Once I reconnected the power cord a few minutes later and this time it just gave a very brief flash, no power led or anything else...

    (I moved this thread from another post, and this is PlainBill's response
    The symptoms suggest the video processor (the Genesis chip at the right side of the board) is being reset. This MAY be due to power supply fluctuations.

    I've marked three voltage regulators (I think) with the numbers 1, 2, and 3. What are the part numbers of these three regulators? If you can locate the datasheets for them, you can anticipate my next question by telling me what the output voltages are when the monitor is working, and when it fails.


    In the last photo you can see the caps I replaced - they have yellow lines by them. I used LXZ or Nichelon new caps.
    Attached Files
  • sceva
    Senior Member
    • Feb 2010
    • 196

    #2
    Re: Dell E176FPf power cycles after being on several minutes

    Starting with the larger one at top, all readings from when it was working well:
    Part # AC 1506, 0549bL
    18.2v, 5.2v, 168ohm, open circuit, 164 ohm

    Part # UTC, LD1117AL, 33AJBSLOQ
    5.2v, 3.3v, closed circuit (to ground)

    Part # AC, 5KJL, 17-18L
    6.4v, 3.1v, close circuit

    NOTE: I took readings with 3 meters. I have an analog meter and an older dmm that gave the same readings. I have a newer dmm that automatically chooses the setting it thinks you want, and it gave readings at 1/2 what the other two meters showed... The last two components readings are from the older meters. The first one is from the newer meter. I know this is confusing... but when I was testing I accidentally shorted pins 3/4 (I think) on the first component and know the board doesn't power up, so I can't test anything else at the moment...

    But back to the original problem, it seems sometimes that jiggling the power cord will cause the problem to start or stop, but not always...

    Comment

    • sceva
      Senior Member
      • Feb 2010
      • 196

      #3
      Re: Dell E176FPf power cycles after being on several minutes

      Wheh! I unplugged it for awhile, and when I plugged it back in, the monitor began working again, except the back light does not come on now. So I must have shorted something out...

      I retested the components and got similar results. I think the newer meter does not read lower voltages? The older dmm shows the following for part AC 1506:
      39.9v, 10.6v, closed circuit, 1.9v, closed circuit

      When I say closed circuit, I mean it reads no voltage, and if I test it with on the ohm setting it shows continuity with some resistance.

      Comment

      • smason
        Badcaps Legend
        • Feb 2010
        • 1652
        • Canada

        #4
        Re: Dell E176FPf power cycles after being on several minutes

        That board looks identical to the 196Fp I'm working on. As soon as my caps arrive, and I get my DMM and soldering station fixed (seems I picked a bad week to get back into electronics repair) I may have some more insight.
        36 Monitors, 3 TVs, 4 Laptops, 1 motherboard, 1 Printer, 1 iMac, 2 hard drive docks and one IP Phone repaired so far....

        Comment

        • sceva
          Senior Member
          • Feb 2010
          • 196

          #5
          Re: Dell E176FPf power cycles after being on several minutes

          I have just ordered an ESR meter myself...

          Comment

          • kc8adu
            Super Moderator
            • Nov 2003
            • 8832
            • U.S.A!

            #6
            Re: Dell E176FPf power cycles after being on several minutes

            the one i have on this box did the same thing.
            all the caps were high esr and many bad solder joints.
            look esp at the transformer.

            Comment

            • smason
              Badcaps Legend
              • Feb 2010
              • 1652
              • Canada

              #7
              Re: Dell E176FPf power cycles after being on several minutes

              Can you get the part number off of U1?
              I can't read it off of mine. It's something like gz9935cn but I can't quite make it out.
              Thanks,
              Steve
              36 Monitors, 3 TVs, 4 Laptops, 1 motherboard, 1 Printer, 1 iMac, 2 hard drive docks and one IP Phone repaired so far....

              Comment

              • sceva
                Senior Member
                • Feb 2010
                • 196

                #8
                Re: Dell E176FPf power cycles after being on several minutes

                Mine is 0Z0036GN, 51894931T, 0541A1

                Comment

                • smason
                  Badcaps Legend
                  • Feb 2010
                  • 1652
                  • Canada

                  #9
                  Re: Dell E176FPf power cycles after being on several minutes

                  Originally posted by sceva
                  Mine is 0Z0036GN, 51894931T, 0541A1
                  Thanks. Turns out the one I'm working on was just 2 bad caps.
                  36 Monitors, 3 TVs, 4 Laptops, 1 motherboard, 1 Printer, 1 iMac, 2 hard drive docks and one IP Phone repaired so far....

                  Comment

                  Related Topics

                  Collapse

                  Working...