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LG 50" PK540 Plasma Clicking, not turning on.

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    #41
    Re: LG 50" PK540 Plasma Clicking, not turning on.

    Originally posted by tom66 View Post
    Do you think it will be possible to probe the AC_DET pin? You may need a piece of wire. Attach the wire to the red probe on your multimeter, and stick the wire on the AC_DET pin. Place the black probe in an exposed screw hole (e.g., for the wall mount.) Set your meter to the 20V DC range and move the probe to the volts/ohms jack. Then plug the TV in. You should measure either 3V or 5V. If it drops to zero during the clicking, you have a very common problem with LG plasmas which is easily fixed .

    In addition, use the ohms range to measure the fuses on the board. Do this with power off and leave the TV for about a minute to discharge the caps. Measure the resistance from one end to another on the 200 ohm range. You should measure close to zero ohms. Don't confuse the open circuit "1" on right hand side with "1.0" ohms. I expect these will be okay as the screen is flickering but it doesn't hurt to be thorough.

    Post a picture of your multimeter if anything is confusing so we can indicate which modes to set the meter to.

    Hi i'm having the same problem LG 50PK350_ZB with the clicking and not turning on just the red standby light showing, the TV was ok till one day it just went off and wouldn't come back on.

    I know this is an old thread but didn't think there was any point starting another on the same problem

    Hope someone can give me a few pointers

    I have checked the 3 large 10 Ohm resistors, Diode @ D304 3 fuses and replaced the voltage regulator and also tried another main board (the one with the scart/hdmi inputs) but this made no difference.
    There was a site on ebay selling 11 SMD resistors the replaced ones on the back of the board but they all have a reading when tested (don't know if its correct) and also if they need to be removed and checked? I was hoping one would be open.

    There was mention of bypassing something to get it working with a resistor added somewhere?

    Could some one please give some detailed instructions on how to do this and what its for.

    Its an old TV and if there was a cheap fix i'd try it but its not worth spending a lot of money on.

    Thanks

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      #42
      Re: LG 50" PK540 Plasma Clicking, not turning on.

      Just to add I seam to be getting 5v on the STBY 4v on the RL ON and about 3v on the AC DET but its hard to tell as it only jumps up briefly as its clicking

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        #43
        Re: LG 50" PK540 Plasma Clicking, not turning on.

        Measure the 3 ceramic resistors on the power supply again. First in residence mode, and then in continuity mode. They are fuseable resistors and may read good one way, but not the other.

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          #44
          Re: LG 50" PK540 Plasma Clicking, not turning on.

          HI thanks for the reply

          They each check out @ 10 Ohm and have continuity

          I also removed them and put 3w across them @ 5v to see if they broke down under load

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            #45
            Re: LG 50" PK540 Plasma Clicking, not turning on.

            Anybody have any more suggestions?

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              #46
              Re: LG 50" PK540 Plasma Clicking, not turning on.

              Originally posted by ben7 View Post
              Could also be a shorted LDO regulator on the processing board.

              -Ben
              what kind of regulator ?

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