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What are these white patches on top of the metal parts of this board?

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    #1

    What are these white patches on top of the metal parts of this board?

    There are these white fairly dense patches on top of the metal parts of the power supply. Does anyone know their purpose?

    Thank you!
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    #2
    Re: What are these white patches on top of the metal parts of this board?

    look like stick on cooling pads ..but only ones i have seen are black

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      #3
      Re: What are these white patches on top of the metal parts of this board?

      I'm seeing just two of them.
      And thats thermal pads for sure.
      Pretty common in laptops to transfer heat from chipset/vrm/vram.
      I have seen them mostly in white color, but also blue (Arctic thermal pads).

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        #4
        Re: What are these white patches on top of the metal parts of this board?

        I reckon that is what they are. Thank you!

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          #5
          Re: What are these white patches on top of the metal parts of this board?

          If the tv has a metal rear cover it could be to isolate the hot side of the power supply from touching the rear cover.

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            #6
            Re: What are these white patches on top of the metal parts of this board?

            Originally posted by R_J View Post
            If the tv has a metal rear cover it could be to isolate the hot side of the power supply from touching the rear cover.
            AFAIK, actually opposite of what you wrote. Its like thin thermal pads between TO-220 and heatsinks which transfer heat and not electricity, just thicker.
            Thermal pads transfer heat from small surface, onto bigger surfaces like metal shield in LCD monitors, to offer better cooling. On small passive-cooled netbooks, thermal pads are often used to transfer heat from processor and chipset to metal plate under keyboard.
            If LCD housing is metal, and manufacturers doesnt wanted to conduct heat from internal cooling, they wont be using anything, just a air gap between housing and hot metal parts inside or use sponge with coated tape which is heat-resistive and doesnt transfer heat (Im unable to find pic of what I mean, but if you're disassembled some notebooks before you surely know what I mean).
            Last edited by BadCon; 01-28-2017, 09:51 PM.

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              #7
              Re: What are these white patches on top of the metal parts of this board?

              Where is the problem? if factory has put it in there's a motivation...

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                #8
                Re: What are these white patches on top of the metal parts of this board?

                Originally posted by BadCon View Post
                AFAIK, actually opposite of what you wrote. Its like thin thermal pads between TO-220 and heatsinks which transfer heat and not electricity, just thicker.
                Thermal pads transfer heat from small surface, onto bigger surfaces like metal shield in LCD monitors, to offer better cooling. On small passive-cooled netbooks, thermal pads are often used to transfer heat from processor and chipset to metal plate under keyboard.
                If LCD housing is metal, and manufacturers doesnt wanted to conduct heat from internal cooling, they wont be using anything, just a air gap between housing and hot metal parts inside or use sponge with coated tape which is heat-resistive and doesnt transfer heat (Im unable to find pic of what I mean, but if you're disassembled some notebooks before you surely know what I mean).
                No your wrong, if the heatsink under the gap filler pad is hot (connected to one side of line voltage) and it comes in contact with the rear cover it makes the whole tv rear cover hot and will give a someone a shock or worse. It could also help with heat transfer I suppose.

                Check the ac voltage between cold chassis ground and the heatsink under the pads and see what voltage you get, If its 0 volts then I guess its just for heat transfer if its around 50 volts or more I would lean more to isolation, manufactures will use whatever they have at the time of manufacture
                Last edited by R_J; 01-29-2017, 03:54 PM.

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                  #9
                  Re: What are these white patches on top of the metal parts of this board?

                  Edit: Never mind.
                  "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
                  -David VanHorn

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                    #10
                    Re: What are these white patches on top of the metal parts of this board?

                    These patches are on one of my monitors and they do separate the metal part of the heatsink from touching metal. The 3rd patch was in the picture but I removed it to show what was under it.

                    On one of the monitors I have which is in the same model they used black plastic on the inside of the metal cover and didn't use white patches. This black plastic separates the metal part from touching the metal cover.

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                      #11
                      Re: What are these white patches on top of the metal parts of this board?

                      They could also serve two functions! Everyone could be right!

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                        #12
                        Re: What are these white patches on top of the metal parts of this board?

                        The way i see it , they serve the two ways , isolating and cooling at the same time .

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