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Dell E173Fpf and burnt resis.

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    Dell E173Fpf and burnt resis.

    Hi!
    I've damaged my Sunday morning and over to read other threads
    I have bought this monitor broken, i found soon Q850 'AP-2761I' power mosfet shorted all sides, R856 is burnt and value is unreadable, the explosion may have destroyed also the near pin of a little smd capacitor (ceramic?)
    wich is connected to ground, the other one leg goes to Vdd of the pwm, i don't know its value , reading threads (by mypc2007) one user Bobdee reveal the value of resistor is 15R0 so like a 15 ohm, watching with a lens
    i see that much probably the first/last cipher is 5, then a R or 0, a 1 and finally
    an half 0 (may be a R but isn't the right pos. for it), reading upside down
    can be 0105 but it has no sense, so is it 5R10, then a 5,1 ohm?? Reading Somtam i found too other broken items so finally i have R856, R861, R859 open, Q850 short, like him, plus C856 open (exploded with R856) and
    R852 (visually a bit burnt/damaged and seems open, near big cap past the bridge) .
    I've also read here about one that had replaced Mosfet and big R869 (or R852 don't remeber) and fixed so. The second problem, R852 has strange colour code, is red-black-silver-gold-white, it has no sense, silver as 3d
    ring.. white as last?? Now i go to ebay to watch for mosfet..

    for picture in other threads:
    https://www.badcaps.net/forum/attach...&stc=1&thumb=1

    #2
    Re: Dell E173Fpf and burnt resis.

    I add in the entry of AC there is a wire instead of the glass fuse, watching the soldering is sure by factory, it's normal? I must replace it?

    Comment


      #3
      Re: Dell E173Fpf and burnt resis.

      Davi.p
      R852 = red black silver gold gives you 0.2 ohms with tollerance of 5%
      You forget the white as that has something to do with the military failure rating as I recall when I had a problem with same resistor

      Comment


        #4
        Re: Dell E173Fpf and burnt resis.

        Davi.p
        I have the E173 and E153 boards with me now
        R856 = 15R0 on both boards
        Have taken reading on E173 resistor and find it open
        So I have taken reading on the E153 and it gives me 15 ohms confirming that it is 15R0
        Anything else I can confirm for you, just ask

        Comment


          #5
          Re: Dell E173Fpf and burnt resis.

          thankyou , i trust you, unfortunately on ebay only one person sells kit for repair,
          and i have to replace mosfet with something similar (i have to spend times watching
          d.sheets uff!) and also little resistors are hard to find nowadays here .. sob!
          For a 40 euro monitor so hard work.. pant! Ok i let you know if i will fix it..
          If you know a search engine capable of find equivalet transistors..
          bye.

          Comment


            #6
            Re: Dell E173Fpf and burnt resis.

            i have replaced mosfet with an STP10NK60Z, a N channel 600V 10A (0,7ohm Rds
            Vgs threshold 4,5v Vgs +-30v Ton 20ns) Original is 650v 10A(1 Rds threshold 4v vgs+-30v ton 16ns) unfortunately shop hadn't smd things i replaced R856 with a normal
            thruhole 15ohm, but i repeat with the lens on mine exploded the first number is 5,
            something like 5R10 (=5,1ohm), anyway the condenser with a normal one 10nF 100v
            (original unknown but another user said probably ok cause serves as anti disturb
            , noise, so it must be little, it's on the Vcc line that powers the pwm at 20-30v)
            i powered up and.. PPaaamM! A fire shot.. ( i dunno why...

            Comment


              #7
              Re: Dell E173Fpf and burnt resis.

              If your board looks like this :
              board
              then R852 is a 0.2ohm 1w metal film
              There are 2 ceramic high voltage caps between the centre heatsink and the 100uF 450V elect. the resistor directly above is the 0.2 ohm, if you have the same board.
              I have an E173FPf monitor where the ceramic cap has ruptured and flashed to the heatsink earth taking out the 0.2 ohm and the 2A mains fuse. The small cap nearest the 100uF is a 10nF 1kV, the ruptured one nearest the heatsink is a 100nF 1kV.
              Last edited by picturevalve; 11-19-2010, 07:55 AM.

              Comment


                #8
                Re: Dell E173Fpf and burnt resis.

                R856 on my board is marked 5R10 and measures 5.1 ohm. C856 I cannot measure properly as it seems to have a 10uF in parallel. HTH.

                Comment


                  #9
                  Re: Dell E173Fpf and burnt resis.

                  Thank you picturevalve, the board is the same!.. is strange for the 2 big resistors, 11 near the little pwm ic and the other near big cap., the colour scheme i remember was different, i remember one guy told to me one is 0,2
                  the other is 0,33-0,3. Unfortunately i have taken the item used and found a
                  fucking wire instead of glass fuse! And the 'a little stupid' guy that sold it to
                  me don't seems so good to solder works, the wire appear a factory job (maybe, who knows?). Ceramic round-flat caps you say, in mine seems good..
                  i will check.. now i had doubts about the optocoupler, when it come i will change it and hope.. about the R856 another guy told me also is 5.1ohm, now i know it for sure, i don't know if was it the reason the first repair try it
                  exploded the 0,3 (or 0,2..) ohm resis. near pwm ic..
                  BYE.

                  Comment


                    #10
                    Re: Dell E173Fpf and burnt resis.

                    Originally posted by Davi.p View Post
                    11 near the
                    correction: "11 near" is "one near"..

                    Comment


                      #11
                      Re: Dell E173Fpf and burnt resis.

                      You will probably find the PWM chip is blown as well.

                      Comment

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