Identify sot-89 part in faulty psu

Discussion in 'General Electronics Chat' started by chunkymonkey909, Aug 19, 2015.

  1. chunkymonkey909

    Thread Starter New Member

    Nov 19, 2014
    2
    0
    Hi, I am trying to repair a switched mode power supply from a very old Toshiba T1200 laptop. I have two of them but they both are faulty - sometimes they work but sometimes they give a flashing red led (error) and no voltage output. One of them has had the electrolytic caps replaced but no change. The other one has a melted sot-89 part which I am unable to identify. There are other sot-89 parts on the psu which look the same but they dont have any markings apart from SG (eg Q6, Q7, Q8, Q9 on left hand side of pic). They all seem to be connected the same ie 2 of the 3 pins are connected together. See link below for pics. The one that has failed has -22v on one of the pins which i believe is lcd supply.
    Anyone care to guess what they are (transistor, fet, ???).

    https://picasaweb.google.com/lh/photo/obNWPUdOQh8Xe2HSTbzZ0gWSseWBgGvOl8DYS_uJyo4?feat=directlink

    Many thanks
     
    Last edited: Aug 19, 2015
  2. chunkymonkey909

    Thread Starter New Member

    Nov 19, 2014
    2
    0
    Just for completeness in case someone else needs this info. Someone has found the part number:-

    U1GWJ49 Schottkey diode
     
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