Asus VE278Q BackLight

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • nv13
    Member
    • Jul 2013
    • 22
    • USA

    #1

    Asus VE278Q BackLight

    Hello all!,
    This monitor was given to me in a state that the LCD image is functional however the backlight was dim and flickering. I tried turning up the brightness on the monitor OSD and the monitor backlight ceased to flicker or function from that point forward. Upon the restarting and subsequent restarts of the monitor it initially flashes quickly and goes out after a split second. It is not the 2 seconds to black as is popular with other monitors. That is not to say the end solution isn’t though. The power button stays blue and the image is still visible albeit with a flash light. Everything else appears functional as normal.

    Here is a run-down of the things that I have done so far (Keep in mind, I am a moderate noob).

    • I have looked for the obvious bulging bad caps. I have found none.
    • I have looked for scorching on all the PCB’s. I have found none.
    • I have checked for shorting out of the LED Backlight connections. I have found none.
    • I have tried connecting the LED backlight strips one a time and in combination to see if the flickering was isolated to a specific short to no avail. I am not sure if there is a way to test with a CCFL bulb as these are LED’s and they are strips and do not appear to be simple wires that can be tapped into.
    • I have not found a fuse as I do not know what to look for (not a blub fuse as I am used to).

    I am in the process of attempting the voltage testing per the guide. Power Supply/Inverter Board? T-Con Board? I am not expecting the T-Con Board to be at fault but I could be wrong.
    I have attached a few images. Please let me know if more information is needed.
    Any advice would be much appreciated.
    Thanks to all!
    Attached Files
    Last edited by nv13; 06-18-2015, 09:00 AM.
  • nv13
    Member
    • Jul 2013
    • 22
    • USA

    #2
    Re: Asus VE278Q BackLight

    If anyone knows what or where I can begin testing the voltage on which boards that may steer me in the right direction. Is there a section of (R)esistors or (C)apacitors and I should isolate and begin with?

    Comment

    • nv13
      Member
      • Jul 2013
      • 22
      • USA

      #3
      Re: Asus VE278Q BackLight

      These are the caps that I have on the power supply/inverter board (this is the tan colored board correct?), assuming it is at fault here. I was unable to test voltages, not entirely sure what I should be done to do so. I do have a multi-meter to test with. I have read that Caps need to be removed to test out of circuit unless using an ESR meter which I do not have. I have read the guides posted here about testing components. Not sure my multi-meter is reading correctly, more likely I am not doing it correctly.

      (2) 1000uF 25v
      (2) 470uF 35v
      (1) 470uF 16v
      (1) 100uF 50v
      (1) 22uF 50v
      (1) 4.7uF 100v

      My questions is what caps should I use and or replace? I was thinking Rubycon but not sure what series and part numbers to get or does my issue reside elsewhere? ie not the power supply/inverter board or caps?
      Thoughts anyone?
      Last edited by nv13; 06-20-2015, 11:04 AM.

      Comment

      • selldoor
        Slow Learner
        • Dec 2010
        • 7870

        #4
        Re: Asus VE278Q BackLight

        Ok - with it all connected up test the voltages on the connector - bottom
        right in Pic1 -has black and red wires. Start by setting your meter on 200VDC
        Black probe on a ground screw and test each wire/pin on the socket.
        If your probes are too fat put a pin or needle in alongside the wire and test to that. If it only reads leaa than 20v then change the scale on the meter for more accurate results.

        Just for information the small red oblong box components are the fuses but they
        seem ok as if not you wouldnt get anything.

        I am not often on the forum at the moment - my Internet has a problem with external interference and as I can only download pictures very very slowly
        I have given up. But I will try and look in to see how you are doing.

        Which socket does the led lights lead plug into.(which pic is it on)
        Please upload pictures using attachment function when ask for help on the repair
        http://www.badcaps.net/forum/showthread.php?t=39740

        Comment

        • nv13
          Member
          • Jul 2013
          • 22
          • USA

          #5
          Re: Asus VE278Q BackLight

          So I should hook everything back together and test voltages. Is this with or without power?
          Thanks for pointing out the fuses.
          The LED "ribbons" connect on "Pic 1" that small green board that is attached to the tan board. Or Pic number 3. Which is a closer image of the board. At the top of it there are 4 ribbon "flip" connectors. Like the type you might see on a laptop keyboard.

          I will check voltages without power at this point. Unless otherwise noted to do so with power (plugged in).

          Comment

          • nv13
            Member
            • Jul 2013
            • 22
            • USA

            #6
            Re: Asus VE278Q BackLight

            Hey thanks for your input selldoor! I appreciate your time.
            I am afraid in my haste that I have shorted out an item "C904" in Pic 1 as shown in "New Image 1" upload. I tried testing voltage without power and received no readings. Powered up and things came to an end fairly quick.

            It no longer powers up however and I do not see any visual scorching or any other abnormalities from to this event.

            I assume this whole power supply/inverter board is beyond saving. I have no idea anymore.

            Again thanks for your help!

            PS any one have a 715G2824-P02-010-001S that they can part with?
            Attached Files

            Comment

            • Lumberjack777
              Badcaps Veteran
              • Dec 2010
              • 464

              #7
              Re: Asus VE278Q BackLight

              That capacitor is easy enough to replace. I suspect you took out the fuse with it. I think it's the red rectangular component in this last picture.

              It depends on how much time and effort you want to put into this repair. And how soon you need this monitor.

              I did find 2 of your boards on eBay.
              1 is from the USA and more expensive.
              2 is from China and cheaper (but it may take a few weeks to get there)
              http://www.ebay.com/sch/i.html?_from...-001S&_sacat=0

              Comment

              • nv13
                Member
                • Jul 2013
                • 22
                • USA

                #8
                Re: Asus VE278Q BackLight

                Yea I was eyeballin that first one Lumberjack777.
                I think the second one is different though... unless that green board can be swapped out as I have four LED input connections instead of one. I bet it would still work but would hate to chance it.

                I am not in a hurry with this unit...it is more of a project than anything else.
                The fuse might be the F901 T4V 250V. There happens to be three which I will probably just replace all of them. I may try to find non working monitors and see if I can use caps and fuses for parts as needed...

                Comment

                • Lumberjack777
                  Badcaps Veteran
                  • Dec 2010
                  • 464

                  #9
                  Re: Asus VE278Q BackLight

                  I'd make sure to get the board that looks exactly the same. You are right.

                  But......if I read correctly.....you'll still have that flicker problem. In my experience it is almost always a bad ccfl (lamp) or the inverter. The inverter is a separate board on your model. So it never was the power board to begin with.

                  You'll need the power board (or fix - check that fuse first)..... then move onto to the flicker issue. That will most likely be a ccfl, or the inverter.

                  Comment

                  • stj
                    Great Sage 齊天大聖
                    • Dec 2009
                    • 30965
                    • Albion

                    #10
                    Re: Asus VE278Q BackLight

                    Originally posted by Lumberjack777
                    then move onto to the flicker issue. That will most likely be a ccfl, or the inverter.
                    it's an LED backlit monitor.

                    Comment

                    • Lumberjack777
                      Badcaps Veteran
                      • Dec 2010
                      • 464

                      #11
                      Re: Asus VE278Q BackLight

                      Oh I see. Duh. So what would he need to fix his flicker issue? Maybe you can help him. Thanks for clearing that up.

                      Comment

                      • stj
                        Great Sage 齊天大聖
                        • Dec 2009
                        • 30965
                        • Albion

                        #12
                        Re: Asus VE278Q BackLight

                        probably need to start with foto's of the ribbons and invertor to work out how many strings of led's it has and what the drive chips are.

                        it's probably a bad led or 2, but first we need to work out how to get them to stay on for a visual inspection.

                        Comment

                        • selldoor
                          Slow Learner
                          • Dec 2010
                          • 7870

                          #13
                          Re: Asus VE278Q BackLight

                          Yes - I would say F901 has likely gone as the capacitor is on the primary side.
                          Not sure how you would short it out unless you put the board an a metal surface
                          while switched on? You need to be really careful as that BIG capacitor can carry 400volts!!

                          Anyway to test the fuse you need to get at the back of the board, set your meter on ohms 200 and test across the two legs of the fuse.
                          NO POWER TO THE BOARD ! Result should be the same as touching the probes together if it blown the meter will show the same as when the probes are apart.

                          Its an easy test so test the other fuses before replacing.

                          For test purposes the replacement fuse does not need to be the same type as long as it is the same voltage and rating.

                          There are quite a few posts on LEDs look at threads by budm at the beginning of the TV forum
                          Please upload pictures using attachment function when ask for help on the repair
                          http://www.badcaps.net/forum/showthread.php?t=39740

                          Comment

                          • nv13
                            Member
                            • Jul 2013
                            • 22
                            • USA

                            #14
                            Re: Asus VE278Q BackLight

                            Quick update...
                            I tested the F901 and it reads nothing where the other two fuses register a reading so I assume that those are good. I will need to replace only the one at this point.

                            As for the LED strips there are four that come off the power supply/inverter board. They identified as KOTL E220709 AWM 20798 80C 60V VW-1 Similar to this http://www.ebay.com/itm/KOTL-E220709...item3f3ecd15b2

                            Upon initial dis-assembly and inspection all cables appeared mint...however since this time one of the cables has been "altered" via children or pets... This should not have anything to do with the flickering as it was doing this before hand and was still doing it afterwards up until the blown fuse of course.

                            So my next question is do I disassemble the LCD panel? I have done this previously but I did not take pictures or anything as it looked a bit scary. I didn't want to damage or scratch something in the process however I can do this again if needed and snap photos.

                            Is the small green board that is attached to the brown power supply board the invertor board?

                            I have attached images of the board that is attached directly to the display itself that the LCD display panel ribbons are attached to as well as an LED back-light ribbon and end.

                            Hope this helps guys.
                            Attached Files

                            Comment

                            • selldoor
                              Slow Learner
                              • Dec 2010
                              • 7870

                              #15
                              Re: Asus VE278Q BackLight

                              Ok How you doing? replaced that fuse yet?
                              Are you back it flashing on for a second or 2
                              Please upload pictures using attachment function when ask for help on the repair
                              http://www.badcaps.net/forum/showthread.php?t=39740

                              Comment

                              • nv13
                                Member
                                • Jul 2013
                                • 22
                                • USA

                                #16
                                Re: Asus VE278Q BackLight

                                selldoor,
                                Sorry, I have no further progress at this point. I still need to locate a fuse for this board before I can move on. Was going to try a local Radio Shack store Monday to see if they had anything in stock before I go online, prices didn't appear that great upon initial search. I will keep you posted as I move along.
                                Thanks for checking in!

                                Comment

                                Related Topics

                                Collapse

                                • DanPoka
                                  Guide me through repairing a Dell p2210f LCD ccfl backlight monitor
                                  by DanPoka
                                  I bought this p2210f dell monitor to fix. Schematic is the same as p2210.
                                  Behaviour is that monitors comes on but then backlight switches off almost instantly. If I look with flashlight I can still find the "No signal message". So definitely a backlight issue. Trying to advance the issue I proved that the protection circuit is switching off the backlight by shorting out C3 and resistor to disable the INL chip then re enable by removing the short.
                                  This is where it gets interesting. When I disassembled the monitor to solder leads on c3 capacitor I noticed the backlight flickered...
                                  02-15-2025, 05:05 AM
                                • bajdik
                                  Richtek LED Backlight Identify IC chip 'CZ=EL 12M' - LCD monitor Samsung LTN173KT01 from Asus K70
                                  by bajdik
                                  Could anyone identify Richtek backlight driver from Samsung LTN173KT01?
                                  There is only "CZ=EL 12M" mark on it. Thank you very much!
                                  04-04-2025, 03:12 AM
                                • Zilicon
                                  NEWSYNC B27F165 MONITOR HAS NO BACKLIGHT. board no: JY85QS_UPH_LS_R10.3
                                  by Zilicon
                                  Greetings everyone.
                                  Please I need help with the above monitor.

                                  Below is the summary of what happened and what I have done:

                                  The monitor started by turning off 2 seconds after it was turned on. It displayed with a backlight when it turned on. However, the standby light remains on after it is turned off on its own, I have to press the power button again to turn it on, but it will go back to standby after 2 seconds.

                                  The backlight driver IC is 0b3350cp.

                                  I applied a 370k SMD resistor on the CMP pin which is pin 6, while the other...
                                  11-07-2023, 09:12 AM
                                • user546087
                                  Keyboard backlight too bright - Asus Zenbook S16 / UM5606
                                  by user546087
                                  Hi,

                                  I have a new Asus Zenbook S16, Model UM5606. Unfortunately, the keyboard backlight is too bright, even on the lowest setting. I have explored several ways now:

                                  - kindly ask Asus for an adjustment - they basically told me to STFU and get lost It is not possible, they say. Of course.
                                  - tint the keycaps from behind - I have already tried that - it is kind of a last resort
                                  - try to find out, how it is done, look at schematics - this is, where we are at.
                                  - maybe get the BIOS modified somehow? This would be the best option but I do not know a lot about...
                                  02-24-2025, 02:03 AM
                                • momaka
                                  HannStar Hanns-G HC194d LCD monitor repair
                                  by momaka
                                  Normally, I never post repairs this quick after I do them, because… I am usually very slow. But today, I’m making an exception here. Why? No idea. Perhaps only because the repair details are still “fresh” in my head… which is ironic, given this is a 16 year old monitor that hardly anyone will care about today. It is new to me, though. I picked it up last November from someone on my local Craigslist. It wasn’t very close to where I live, but was close to a family friend that I had to go visit anyways. So after watching the posting on Craigslist for a few weeks and seeing it getting...
                                  03-15-2023, 10:17 PM
                                • Loading...
                                • No more items.
                                Working...