Is BN44-00444A power supply from PN51D550C1F bad?

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  • Pioneerx01
    Badcaps Veteran
    • Apr 2015
    • 241
    • US

    #1

    Is BN44-00444A power supply from PN51D550C1F bad?

    I got my hands on PN51D550C1F. I have determined that power supply is bad, as it is not giving me Vs or Va voltages. Also the Y sustain board was fried, as I have found a loose screw between the board and the panel with nice black burn mark on both. I assume that both YSUS and PSU failed because of the screw. Y driver board appear to be OK as well as ZSUS.

    I have purchased used PSU and YSUS. PSU arrived today. I have plugged it in, minus the cable that connects to YSUS and ZSUS boards subsequently, just to see if I get proper voltages. Va is within one volt of nominal but Vs is reading 245V where 207V is nominal.

    Technically speaking when you put a load on power source the voltage will drop. I am just not sure how true it is on TV power supplies or if it will drop that much that it will be nominal again when under load.

    Should I return it?
    Thanks
  • tom66
    EVs Rule
    • Apr 2011
    • 32560
    • UK

    #2
    Re: Is BN44-00444A power supply from PN51D550C1F bad?

    245V is very high, and it is unusual for it to be that high even without load. How confident are you that your multimeter is working OK?
    Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
    For service manual, schematic, boardview (board view), datasheet, cad - use our search.

    Comment

    • Pioneerx01
      Badcaps Veteran
      • Apr 2015
      • 241
      • US

      #3
      Re: Is BN44-00444A power supply from PN51D550C1F bad?

      I double checked with my older and cheaper volt meter. It read 240V and other one re-read at 243V.

      Comment

      • tom66
        EVs Rule
        • Apr 2011
        • 32560
        • UK

        #4
        Re: Is BN44-00444A power supply from PN51D550C1F bad?

        You could use two 120V light bulbs wired in series to test Vs load.
        I use 230V lightbulb myself. works great because it can be run continuously to load the PSU with ~100W.
        Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
        For service manual, schematic, boardview (board view), datasheet, cad - use our search.

        Comment

        • Pioneerx01
          Badcaps Veteran
          • Apr 2015
          • 241
          • US

          #5
          Re: Is BN44-00444A power supply from PN51D550C1F bad?

          It worked great. It took some creative wiring as I am in US (110V) and most of my lights are CFL or LED. Once loaded the voltage dropped to nice 208V (207V Nominal)

          Thanks, good trick.

          Comment

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