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    #1

    3.3k resistor

    Ok i am trouble shooting a power supply from a ilo Lct42ha36 that will not turn on,it has the red indicator light on and will flicker when the power button is pushed. After taking the back off i have found 5 bulged Capxon capacitors on the power supply. It is getting the 5vsb but no 3.3ps-on. So can the bulged caps cause the logic board to not send the 3.3? And when jumping the 5vsb to the 3.3ps-on you refer to a 3.3k resistor. I am ordering the caps from digi-key and also want to order a resistor but it wants watts so can someone let me know what resistor is suitable for this please.
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    #2
    Re: 3.3k resistor

    I don't understand how you figure out that resistor, how your logic goes.

    The resistor has color lines on it which tell you the value in ohms, don't just estimate the value of some resistor based on some wacky logic.

    As for watts rating, that you can usually determine by the size of the resistor. Generally, it's not a problem if you use a resistor with a higher watts rating, that just means it won't heat as much as a resistor with lower watts rating.

    If your resistor is too low on watts, it will overheat and burn out.

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      #3
      Re: 3.3k resistor

      What i am refering to is after read some posts on testing the power supply we can use a 3.3k resistor to jump between the 5 volt stand by and the ps-on which should recieve 3.3volts from the logic board when the power button is pushed which in then turns on the rest of the power supply and then we can test for the 12volt and 24 volts.

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        #4
        Re: 3.3k resistor

        1/2 watt should be fine.

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          #5
          Re: 3.3k resistor

          Thanks for your replies guys.

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            #6
            Re: 3.3k resistor

            I am testing the voltage regulator U3 and with black lead to 1 and red to 2 i get 3.24v, black to 1 red to 3= 5.08, black to 2 and red to 3 = 1.83.
            is the 3.24 to low thus a bad voltage regulator? it is a ams1117 3.3 0638.
            Also i have some new AP1117EG-13 regulators that i used for a vizio repair, would these work for a replacement on this one?
            Last edited by eagle00799; 03-10-2013, 11:08 PM.

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              #7
              Re: 3.3k resistor

              Originally posted by eagle00799 View Post
              What i am refering to is after read some posts on testing the power supply we can use a 3.3k resistor to jump between the 5 volt stand by and the ps-on which should recieve 3.3volts from the logic board when the power button is pushed which in then turns on the rest of the power supply and then we can test for the 12volt and 24 volts.
              Another way to achieve the same thing is to put two fresh AA batteries in series. This is enough to give > 3V DC which is what most control signals like PS_ON, BL_ON, etc need.
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                #8
                Re: 3.3k resistor

                I might have measured the voltage regulator the wrong way, i read it somewhere. but i measured it this time by grounding the black lead to a chassis screw and got the following readings. pin 1=0.00, pin 2=3.24,pin 3=5.08. When i try to measure voltage at the ps-on when i try to turn it on i get readings in motion including OL. Any ideas?

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                  #9
                  Re: 3.3k resistor

                  Hi guys, i am hoping one of you can give me direction with this ILO lct42ha3. I know its old and out dated to say the least but it was a freebie so i thought i might be able to bring it back to life cheaply.
                  I am not getting the 3.3volts to the ps-on but i do have the 5volts to standby,the tv would not come on it would just stay in standby with the red light on. i do have some bulged caps on the power supply and have them on order. I put 2 AA batteries together and jumped the ps-on and the tv came on and worked as it should,I even disconnected the batteries and it stayed on so are the batteries energizing something? if i shut the tv down it will not start back up without the batteries in place. Can these bulged caps cause this? I included a few pics of the main board and power supply
                  Attached Files

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                    #10
                    Re: 3.3k resistor

                    Yes, bad caps can cause intermittent or unstable power. Replace those to get a baseline before doing any further tests.
                    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.

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                      #11
                      Re: 3.3k resistor

                      Thanks Tom, I will let you know the outcome.

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