Dell 2408WFPb / 2408WFP - No Power

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Biessea
    Member
    • Nov 2017
    • 17
    • Italia

    #61
    Re: Dell 2408WFPb / 2408WFP - No Power

    Ah ehy, these are my boards photos.





















    Comment

    • Biessea
      Member
      • Nov 2017
      • 17
      • Italia

      #62
      Re: Dell 2408WFPb / 2408WFP - No Power

      Originally posted by eaarnoudse
      Hi Biessea,

      try to heat up the heatsink on the mainboard and see whether the monitor powers on. I think you have the same problem as other forum members here.

      Never buy a Dell monitor again
      hey, I cleaned up the power supply board (there was a lot of dust at the end, I have this monitor bought at its exit on market, 2008 september so it's 9 years old and It's normal to find some dust solidificated)...then I tried to give current and the power on button LIGHT ON!
      I was happy to see that so I decided to reassembly all and now monitor works perfectly! I'm so happy, this was the first time that I tear down my Dell and I succeded in my mission!
      I'm so happy now, vertical lines appears like it do lately but after about ten minutes they disappear and the monitor works perfectly!
      WOW!

      Thanks for the support, anyway.

      Comment

      • eaarnoudse
        Erwin Aarnoudse
        • Mar 2016
        • 30
        • The Netherlands

        #63
        Re: Dell 2408WFPb / 2408WFP - No Power

        Ok, that is great. But for a double check, you should cool down your monitor completely and check if it turns on again.

        Comment

        • dbrubeck
          New Member
          • Nov 2017
          • 8
          • USA

          #64
          Re: Dell 2408WFPb / 2408WFP - No Power

          Originally posted by eaarnoudse
          I am also trying to repair a Dell 2408WFPb. I have the same problem as mentioned in one of the previous posts. A led light that blinks one time and the monitor won't turn on. The power supply is OK, because CN701 has about 24V on the output. The reason that the inverter board doesn't power on is simple. The first black wire on CN701 is the ON/OFF signal and it's 0V.

          I started to suspect the mainboard and I found a way to power up this board. It seems like there are two main sections on it. Each section has a big chip, a crystal and a voltage regulator. First, I measured the section at the side where the power supply cable comes in. The crystal has a perfect sine wave and the voltage regulator shows a perfect 1.8V. But there is no voltage on the second crystal and voltage regulator.

          I heated the heatsink and the onboard chip in the first section very carefully with a hot air rework station. Then I tried to power up the monitor and it was working great again. I waited some time until the heatsink was cooled down. The monitor did not start up. I heated the heatsink and chip again and the monitor was working fine.

          I think there is a cold solder joint in one of the pins of this chip. Maybe a reflow precedure will solve the problem, although this method is not very reliable. I hope this post will help other people to troubleshoot this specific problem.

          Greetz,
          Erwin
          Thanks Ewrin, this was my exact problem.

          By heating the big chip on the logic board to around 125 F (by blowing heat onto the heatsink, and measuring with an IR thermometer), I was able to get the monitor to turn on normally. After the chip cooled down, it would not turn on. Same results on repeat.

          I expect that by leaving the monitor in standby, there will be enough heat generated to keep this chip warm and therefore allow the monitor to function indefinitely.

          If the monitor gets turned off and cools, I should be able to boot the monitor by using a hairdryer through the lower vents to heat up the insides to ~125 F.

          I'm curious if people on the board think that the root cause is inside the chip or a bad solder joint to the logic board. If this happens again, I might try a full reflow with flux and a heat gun and see if it makes a permanent fix.

          Thanks!

          Comment

          • budm
            Badcaps Legend
            • Feb 2010
            • 40746
            • USA

            #65
            Re: Dell 2408WFPb / 2408WFP - No Power

            Since there are lytics caps close by you may want really localized the heat or trying to localize the heat to the caps only and see what happen.
            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

            • eaarnoudse
              Erwin Aarnoudse
              • Mar 2016
              • 30
              • The Netherlands

              #66
              Re: Dell 2408WFPb / 2408WFP - No Power

              Hi dbrubeck,

              Another forum member (YulCmr) did some really interesting research lately. He did an X-Ray photography to check whether or not bad solder joints were present on the board. And the conclusion was there were no bad joints and all balls were OK. I am still convinced that the chip is damaged internally. And that makes the monitor immediately beyond repair...:-(

              Comment

              • AlaskaCC
                New Member
                • Nov 2017
                • 8
                • United States

                #67
                Re: Dell 2408WFPb / 2408WFP - No Power

                I recently purchased a 2408WFP and have only been able to get the power light to come on a few times but was never able to get an on-screen display. I am a neophyte at component repair but am fair with a soldering tool. I was not able to detect any obvious problems through visual inspection.

                After reading through the thread, I have confirmed there is 23.56 VDC at CN701. I checked every wire at the connector. The 23.56VDC is on the green wire and the yellow wire. I am not sure what else to do at this point. I can purchase a replacement board for ~$40 but hate to do that. I would appreciate some suggested next steps. Thank you.

                Comment

                • eaarnoudse
                  Erwin Aarnoudse
                  • Mar 2016
                  • 30
                  • The Netherlands

                  #68
                  Re: Dell 2408WFPb / 2408WFP - No Power

                  Hi AlaskaCC, I am afraid you purchased a bad 2408WFP and maybe your seller was aware of these problems before selling this monitor to you. I repaired about 3 2408WFP monitors and in all cases I had to replace the mainboard. I think this will be the only option for you.

                  You can also try to heat up the heatsink and see if it comes live. Good luck and keep us posted.
                  Last edited by eaarnoudse; 11-23-2017, 02:40 AM.

                  Comment

                  • AlaskaCC
                    New Member
                    • Nov 2017
                    • 8
                    • United States

                    #69
                    Re: Dell 2408WFPb / 2408WFP - No Power

                    Thanks for the recommendation. I will find a source for the mainboard and let you know the outcome.

                    Comment

                    • eaarnoudse
                      Erwin Aarnoudse
                      • Mar 2016
                      • 30
                      • The Netherlands

                      #70
                      Re: Dell 2408WFPb / 2408WFP - No Power

                      I bought the last one on AliExpress 2 weeks ago. I hope you will find a source elsewhere. Good luck :-)

                      Comment

                      • AlaskaCC
                        New Member
                        • Nov 2017
                        • 8
                        • United States

                        #71
                        Re: Dell 2408WFPb / 2408WFP - No Power

                        I purchased a replacement mainboard from an eBay seller that did the trick. I just completed the install. The monitor is back in business! Any idea what components fail on the mainboard or what causes the breakdown?

                        AlaskaCC

                        Comment

                        • eaarnoudse
                          Erwin Aarnoudse
                          • Mar 2016
                          • 30
                          • The Netherlands

                          #72
                          Re: Dell 2408WFPb / 2408WFP - No Power

                          Hi AlaskaCC, great that you fixed your monitor with the replacement part. As mentioned above, the problems are caused by the big chip (with the big heatsink on it). I replaced this mainboard for my customer last week and that monitor is working fine too.

                          Comment

                          • pvb_astro
                            New Member
                            • Jan 2017
                            • 3
                            • United States

                            #73
                            Re: Dell 2408WFPb / 2408WFP - No Power

                            I have the same symptoms as Sparrow-- but even after reading all the material here, no luck understanding. Power supply board appears to be good. later posts mention the heat gun solution, might try that next.

                            I"m an electrical engineer, but not a great technician.. workmanship issues.

                            bicycle's schematic is helpful, but my board might be slightly different, u601 is a NCP1203 for instance. An odd note- -D608 is missing, but so is the same diode on Sparrow's pictures. The schematic doesn't show CN702 which goes to the lamp high voltage supplies. is there a on/off control wire going over there?

                            Power on LED flashes when AC applied. PSU output at CN701 is 23 volts, Vcc for U601/6 is 15v, U601/1 adj= 0.99v, u601/2 FB is 1.00v. All good. A bypass capacitor on one IC on the main CPU board is 2.5volts. The opto isolators IC652 and IC602 appear to be off, U652/4 is 15volts, U602/4 is 1.00 volts, suggesting power is not commanded off?
                            Attached Files

                            Comment

                            • eaarnoudse
                              Erwin Aarnoudse
                              • Mar 2016
                              • 30
                              • The Netherlands

                              #74
                              Re: Dell 2408WFPb / 2408WFP - No Power

                              Try the heat gun solution...:-)

                              Comment

                              • wakoautz
                                New Member
                                • Mar 2018
                                • 2
                                • Singapore

                                #75
                                Re: Dell 2408WFPb / 2408WFP - No Power

                                Newbie here. Found this forum after searching for a fix for my 2408. Same issue as most of you guys here, green led on and that's it. I might want to try the heat gun solution before anything else and let everyone know the results.

                                Comment

                                • sirzur
                                  Member
                                  • Nov 2007
                                  • 15

                                  #76
                                  Re: Dell 2408WFPb / 2408WFP - No Power

                                  So I wanted to post my workaround (NOT fix) for the Dell screen not [powering on. But to recap

                                  • The fix is to heat up the heatsink on the onboard BGA chip
                                  • Seem to imply that the BGA solder is bad, but someone had reflowed the BGA chip and that did not fix the problem
                                  • X-ray photography shows that the BGA solder balls to be intact
                                  • Speculation that one of the internal pins broken and only bridged with heat
                                  • I confirmed that a hot hair dryer on the heatsink for a few minutes will subsequently allow the monitor to light up

                                  Hack uses two resistors powered by a USB 5V source to heat up the heatsink of the BGA chip. The basics of the USB heater design are:

                                  • 2 X 3W, 6.8 ohm connected in series to USB source
                                  • Heat resistant sleeve where it contacts the heatsink
                                  • V = I X R, therefore that current in the circuit is about 0.37A, below the 0.5A specification of a USB port
                                  • Heating power = V X I = 1.8 watts between the two resistors, so I chose 3W rated resistors for adequate safety margin

                                  The implementation was as follows:
                                  • Old USB cable, but doubled up the line to reduce line resistance (Data+ and Data- cable used for power and neutral respectively)
                                  • Heat sleeves to resistors, between resistors and also from resistors
                                  • When circuit is soldered, do a trial with a 5V source to confirm that resistors heat up
                                  • Outer heatsink fins bent outwards to create space for resistors. Resistors in contact with heatsink and just held in place by friction.
                                  • Ensure no bare wire contact with heat sink
                                  • USB cable routed under boards
                                  • Cut made in right protective stainless steel cover and also screen back cover to allow access for USB cable
                                  • I would strongly recommend to connect power to the USB cable to confirm that the heatsink is being heated up before reassembling the monitor







                                  I attach some photos to show final implementation. To use it, either connect the "new" USB to a 5V source (a phone charger works) for a few minutes. I find that 2-3 minutes is all that is required on mine. Alternatively, power up the monitor - despite the screen not lighting up, there is power to the USB ports which can be used to heat up the heatsink.

                                  Then power down the monitor at the mains and reapply power to the monitor and it should fire up. The reapplication of power is a necessary step as just heating the heatsink with power turned on to the monitor will NOT light up the screen
                                  Attached Files

                                  Comment

                                  • eaarnoudse
                                    Erwin Aarnoudse
                                    • Mar 2016
                                    • 30
                                    • The Netherlands

                                    #77
                                    Re: Dell 2408WFPb / 2408WFP - No Power

                                    Wow, nice work man! :-)

                                    Comment

                                    • Joontree
                                      New Member
                                      • Jun 2018
                                      • 3
                                      • US

                                      #78
                                      Re: Dell 2408WFPb / 2408WFP - No Power

                                      Hey guys, I have a 2408wfp that has been having issues as well. Recently I powered it on to find all blacks are being rendered as greens, some blues as pinks, and an overall static/grainy appearance to the image. These symptoms are consistent regardless of cabling or image source. The menu system and all buttons still work, though a factory reset didn't help. At first I suspected a bad cap but a visual inspection of the boards didn't reveal any obviously blown or bulging caps or components. I was wondering if anyone has had any experience with similar symptoms or any ideas for what to look at when troubleshooting for this specific issue. I can post pictures if that would be helpful.

                                      Comment

                                      • eaarnoudse
                                        Erwin Aarnoudse
                                        • Mar 2016
                                        • 30
                                        • The Netherlands

                                        #79
                                        Re: Dell 2408WFPb / 2408WFP - No Power

                                        I think there are 2 possible causes. Maybe your T-Con board, or your LCD panel is faulty. I would try to replace the T-Con board first, because these board aren't very expensive. When you LCD panel is faulty, that will mean the end of your monitor...

                                        Comment

                                        • budm
                                          Badcaps Legend
                                          • Feb 2010
                                          • 40746
                                          • USA

                                          #80
                                          Re: Dell 2408WFPb / 2408WFP - No Power

                                          Originally posted by Joontree
                                          Hey guys, I have a 2408wfp that has been having issues as well. Recently I powered it on to find all blacks are being rendered as greens, some blues as pinks, and an overall static/grainy appearance to the image. These symptoms are consistent regardless of cabling or image source. The menu system and all buttons still work, though a factory reset didn't help. At first I suspected a bad cap but a visual inspection of the boards didn't reveal any obviously blown or bulging caps or components. I was wondering if anyone has had any experience with similar symptoms or any ideas for what to look at when troubleshooting for this specific issue. I can post pictures if that would be helpful.
                                          Did you try re-seating the LVDS cable yet?
                                          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

                                          Related Topics

                                          Collapse

                                          • Bowline
                                            Dell E6400 PT434 type Battery Charging Stuck at 1%. Battery Pinouts?
                                            by Bowline
                                            My question pertains to understanding the control circuity inside a Dell PT434 type battery used in Dell E6400, E6410 and other Dell notebooks?

                                            Does anyone have a circuit diagram for the inside of a Dell PT434 battery and/or a description of how the control lines work to control this battery?

                                            My reason for asking is I have a battery which I cannot get to charge beyond 1% in a Dell E6410 or E6400.
                                            The LED bar graph charge indicator on the battery shows one LED lighted when the info button is pressed.
                                            I have tried multiple different Dell power adapters. My Dell...
                                            06-11-2025, 10:13 AM
                                          • Cemal Odabasioglu
                                            MacBook Pro A1707 Motherboard Diagnostic Help – CD3215 heating and Fluctuating Rails
                                            by Cemal Odabasioglu
                                            Hello everyone,

                                            I'm currently diagnosing a MacBook Pro A1707 motherboard that does not power on. I've gathered some data but am stuck and need expert advice.
                                            Note that i'm a beginner in electronics and i'm trying to learn while trying to repair this macbook that my work gave me. I'm really curious and love understanding how thing works and i already learned so much.

                                            Only one usb c port is taking 20v and have 12.5v on PPBUS_G3H. when trying other ports, 2 are not going to 20v and one is going to 20v but the CD3215 is getting really hot.

                                            Observations...
                                            01-14-2025, 03:54 PM
                                          • F R 2568
                                            Dell Latitude 5420 does not start (no post) need help to find the reason why
                                            by F R 2568
                                            Hello all,

                                            this is my first post, so if I make mistakes please do not hesitate to point them out, thank you in advance.

                                            I got a Dell Latitude 5420 (Service Tag: 7RFM6D3, Motherboard: GDF40 LA-491P Rev.: 2.0 (A01)) which does not start and I want to repair it. These are the symptoms:

                                            If the laptop is only connected to the AC adapter (battery removed):

                                            When I press the power button, the keyboard backlight and the display backlight are turning on. Caps key light is lightning, but key does not respond to pressing it.

                                            The power/battery...
                                            01-08-2025, 05:45 AM
                                          • diamon
                                            Looking for Dell Latitude 5520 / 5530 / 5540 RJ45 network connector replacement
                                            by diamon
                                            I have a Dell Latitude 5530 with a damaged RJ45 network connector. See the attached pictures.

                                            Have already searched on Farnell / Aliexpress / Ebay and had contact with several suppliers on Aliexpress and Ebay, but they cannot deliver this connector.
                                            Is there someone inside the EU, who has these connector(s) or perhaps defective motherboard(s) for these laptop models I have mentioned in the topic title.

                                            Pictures of these boards:
                                            Dell Latitude 5520 https://www.ebay.com/itm/256052956663
                                            Dell Latitude 5530 https://www.ebay.com/itm/125844181534
                                            Dell...
                                            02-28-2024, 12:51 PM
                                          • OntarioTL
                                            Dell 5410 greyed out BT
                                            by OntarioTL
                                            Well I've learned something new today. Of all the Dell laptops I've come across I have never seen bluetooth greyed out, and only to learn this is during the build from Dell factory. I've tried to pull the original BIOS and fix with another dell with the same issue on the forums, however the original was not recovered from the forum upgrade so I cannot do a comparison to attempt the fix on my own.

                                            If someone could help me out with this unit and I'll try the next one as so far I have 2 on my desk with this issue. Thanks in advance!

                                            Dell Lattitude 5410
                                            Service Tag...
                                            Today, 01:28 PM
                                          • Loading...
                                          • No more items.
                                          Working...