ASUS VE278 No power

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  • darshanaj
    New Member
    • May 2013
    • 3
    • Australia
    #1

    ASUS VE278 No power

    I have an ASUS VE 278 monitor. When I plugged it to the main nothing comes, not even the LED. Can the no power situation happen because of bad main board? or does it happen due to bad power board?. Sorry this is the first time im trying to fix a monitor so I dont know much jargons
    Tags: None
    • darshanaj
      New Member
      • May 2013
      • 3
      • Australia
      #2
      Re: ASUS VE278 No power

      Hi,
      I have attached the photos of the power board. All the caps are seems to be fine. I measure the voltage of the big capacitor. It is 340V. There are 2 set of wires connects to the main board . I connected the board to AC line and then I measure the voltages. The 3 wires which are at the top part of the board delivers +18V (yellow is + and black is -). Then I check the other bunch of wires. Red wires deliver +5v and it has a yellow wire which is named as DIM does not have any voltage with ground(Black) and the green wire is the on/off. I did this measurement without turning on the power supply from the control board. Are those measurements look normal?
      Attached Files

        Comment

        • darshanaj
          New Member
          • May 2013
          • 3
          • Australia
          #3
          Re: ASUS VE278 No power

          I read some other thread(https://www.badcaps.net/forum/showthread.php?t=28447). It says if +5v line is ok, then it must be a problem with the main board because from +5V the power LED must be turned on. But without sending the power ON signal why does the power board output +18V to the main board? I measured the voltage for LED backlit module its +17V is that normal too?

            Comment

            • jhabers
              New Member
              • Nov 2014
              • 2
              • USA
              #4
              Re: ASUS VE278 No power

              Did you ever find anything out about this? I have the same issue. I took the 2 boards out. If I have the power supply with the board hooked up I get no lights on the led switch board. If I measure the voltage that should be 5 volts I get it jumping from 1-3 volts all over the place.

              I then removed the power supply and hooked up an external 5V source to the logic board. The lights on the power switch now work and I can turn the switch on and off.

              Im thinking that it is the power supply that is bad even though under no load I get 5V, but when under load it jumps all over the place.

              Any thoughts? Thinking maybe a cap but they all look good and they are about a dozen or so. Any way to test them to see what one is going bad if its a cap?

                Comment

                • budm
                  Badcaps Legend
                  • Feb 2010
                  • 40746
                  • USA
                  #5
                  Re: ASUS VE278 No power

                  Is this the exact board as shown in the picture in this thread? If it is, you should check that small lytics cap C908 (START UP CAP) for correct capacitance and ESR next the big black main filter cap laying on its side.
                  Never stop learning
                  Basic LCD TV and Monitor troubleshooting guides.
                  http://www.badcaps.net/forum/showthr...956#post305956

                  Voltage Regulator (LDO) testing:
                  http://www.badcaps.net/forum/showthr...999#post300999

                  Inverter testing using old CFL:
                  http://www.badcaps.net/forum/showthr...er+testing+cfl

                  Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                  http://s807.photobucket.com/user/budm/library/

                  TV Factory reset codes listing:
                  http://www.badcaps.net/forum/showthread.php?t=24809

                    Comment

                    • jhabers
                      New Member
                      • Nov 2014
                      • 2
                      • USA
                      #6
                      Re: ASUS VE278 No power

                      Originally posted by budm
                      Is this the exact board as shown in the picture in this thread? If it is, you should check that small lytics cap C908 (START UP CAP) for correct capacitance and ESR next the big black main filter cap laying on its side.
                      yes same board. How would I go about testing that cap? Also I get 5V out of the power supply with no load on it. Could it still be the start up cap?

                        Comment

                        • budm
                          Badcaps Legend
                          • Feb 2010
                          • 40746
                          • USA
                          #7
                          Re: ASUS VE278 No power

                          You need to put a resistor to load the power supply and see if it can maintain 5V. 10 Ohms 5W resistor will simulate 0.5A load.
                          Do you have meter that can check capacitance and ESR? Or do you have small value caps (22~56uF 25V or more) laying around?
                          Last edited by budm; 11-21-2014, 04:19 PM.
                          Never stop learning
                          Basic LCD TV and Monitor troubleshooting guides.
                          http://www.badcaps.net/forum/showthr...956#post305956

                          Voltage Regulator (LDO) testing:
                          http://www.badcaps.net/forum/showthr...999#post300999

                          Inverter testing using old CFL:
                          http://www.badcaps.net/forum/showthr...er+testing+cfl

                          Tear down pictures : Hit the ">" Show Albums and stories" on the left side
                          http://s807.photobucket.com/user/budm/library/

                          TV Factory reset codes listing:
                          http://www.badcaps.net/forum/showthread.php?t=24809

                            Comment

                            • Sam1976s
                              New Member
                              • Mar 2021
                              • 1
                              • Sverige
                              #8
                              Re: ASUS VE278 No power

                              I also have problems with this monitor. The resistor R914 near the large capacitor, seen in the picture is 14A written on it. It is broken, does anyone know if it is a consequential error and if so what could be the cause?

                              Then I can not read which resistor it should be as it is burned on my SMPS

                                Comment

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