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Dell E177FPf No Power

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    #21
    Re: Dell E177FPf No Power

    Originally posted by retiredcaps View Post
    Well, that is good news. You may have had a poor solder joint on that cap?



    Thanks for the offer, but I'll pass.

    Perhaps PlainBill can make use with just the eeprom chip from board "A"?
    Let's see, 'A' is the board with an unstable power supply. Yes, I definitely would like that board. Billy66 if you are willing to ship only the power / inverter / logic board to me, PM me and we'll make arrangements on shipping costs.

    PlainBill
    For a number of reasons, both health and personal, I will no longer be active on this board. Any PMs asking for assistance will be ignored.

    Never be afraid to try something new. Remember, amateurs built the ark. Professionals built the Titanic.

    Comment

      #22
      Re: Dell E177FPf No Power

      PlainBill... no problem.

      But, I do have another issue with the working monitor, that I did not notice at first. The screen is extremely blue tinted. If I bring up the OSD, it is normally colored. So, I first checked my computer with another monitor, not that. I replaced the VGA cable, not that. So I thought maybe I didn't notice the blue color at first due to it not being there... I powered down the monitor, let sit an hour to cool... and turned on and it is still blue. I just didn't notice at first. Any ideas on this one? I assume it is on the video side of the card... where to start looking? I'm half tempted to move all the power supply parts over to the other board to bring it to life... but realize that I'm learning nothing that way. Can someone point me in the right direction? And yes, I have tried to adjust the settings on the monitor...

      Thanks again for all the help.

      Comment

        #23
        Re: Dell E177FPf No Power

        You have of course done the obvious and performed a factory reset on the monitor?

        Otherwise, try DVI, assuming it has DVI. Rules out a dodgy VGA port.

        Comment

          #24
          Re: Dell E177FPf No Power

          Yeah, did factory reset... same. And it is only VGA port. But good idea.

          Comment

            #25
            Re: Dell E177FPf No Power

            Do all of the colours display properly, but with a blue tint, or are you missing red?
            Bring up a colour palette in paint to confirm.

            My suggestion after, would be to try re-soldering the VGA port connections.

            A slight anecdote, I have a VGA cable on my KVM with a damaged pin, any machine connected will show up black and white when on a BIOS screen, but works fine once in an OS.

            Comment

              #26
              Re: Dell E177FPf No Power

              Have you tried reseating the ribbon cable from the LCD panel to the circuit board. If that doesn't work, try swapping ribbon cables with monitor A.

              Comment

                #27
                Re: Dell E177FPf No Power

                I tried reseating the cable... but figured it wouldn't work. The On Screen Display works. i.e. when you press menu you get the options to adjust and stuff... and it looks perfect.

                Maybe I am missing red. When I mad the background all red... it was purpleish lavender? I will try the re-soldering of the VGA port connections.

                Comment

                  #28
                  Re: Dell E177FPf No Power

                  OK, just noticed something with this issue. When I first hook up the monitor to the power cable after sitting for a bit, the color comes on normal. After about 10 seconds of being on, I can see the screen switch to the blueish color. I haven't opened it up yet to check the VGA connections... but this leads me to believe they would be good.

                  Comment

                    #29
                    Re: Dell E177FPf No Power

                    Wiggling the VGA cable doesn't help?

                    Comment

                      #30
                      Re: Dell E177FPf No Power

                      Nah, it doesn't do anything. I checked the factory settings and the lamp has 24000 hours on it... could there be something to that? Though, I thought when the bulbs start to go or go... it is a pinkish color?

                      Comment

                        #31
                        Re: Dell E177FPf No Power

                        Yes, things will go pink when the CCFLs are failing.
                        My re-capped 'Proview' monitor with well used CCFLs starts off very pink and gets better as it warms up.

                        Comment

                          #32
                          Re: Dell E177FPf No Power

                          OK. Mine is definitely not pink, but blue. And it doesn't get better when it warms up. Looks like I'll have to pull it apart again.
                          Last edited by billy66; 09-30-2010, 01:13 PM. Reason: Typo

                          Comment

                            #33
                            Re: Dell E177FPf No Power

                            OK. I've decided to give up on the bluish tint monitor and try to repair board A. Here is a recap of what is and what has been done:

                            Board A... when plugged in, no LED. The transformer T850 clicks on and off... voltage at U850 pins 3 & 7 bounce all over the place (11 -16VDC).

                            Here is what I've done:

                            - Recapped entire secondary side... no changes
                            - Replaced transformer T850 from known good board (no change)
                            - Replaced I850 from known good board... did this cause I850 supplies pin 2 of U850 and wasn't getting anything out of pins 3 or 4 on I850. After swap, T850 stopped clicking. Also, U850 pins 3 and 7 now have 24.8V steady (not sure if this is high. The known good monitor had 16Vs)
                            - Decided to replace U850 from known good monitor as I found that pin 8 on U850 was only giving output of 0.25v and the known good monitor was putting out like 20v or so. This voltage goes to the gate of Q850... Q850 gate on the known good was seeing 3.58v. On the bad monitor, it was only seeing .02v... maybe not enough to turn on Q850?

                            So after swap of U850, here is where I stand:

                            Monitor wont power on. No LED, no picture, nothing. The transformer T850 clicks once or twice (sounds like it is charging up). Voltages are as follows:

                            - Filter cap: 156V
                            - U850 Pin 1- 0
                            2- 2.6V
                            3- 24.8v
                            4- 1.29v
                            5- 4.5v
                            6- 0.75v
                            7- 24.7v
                            8- 0.25v

                            - I850 pin 1- 99.4v
                            2- 98.4v
                            3- 0
                            4- 2.6v

                            - Q850 G- 0.25v
                            D- 155v
                            S- 0.008v

                            Any ideas?
                            Attached Files

                            Comment

                              #34
                              Re: Dell E177FPf No Power

                              Being this board is an "all-in-one" board with the inverter, power, and logic all on one... there is no cable between the boards... makes it hard for me to find test points. Can anyone point me in the right direction to take some measurements for the 5V, 3.3V, and 12V?

                              Also, should I start another thread for this monitor alone?

                              Comment

                                #35
                                Re: Dell E177FPf No Power

                                Originally posted by billy66 View Post
                                Can anyone point me in the right direction to take some measurements for the 5V, 3.3V, and 12V?
                                1) D854 - dual diode should read 12V DC on middle pin ore slightly more (my guess)
                                2) 5 legged voltage regulator chip marked 1506 - look up datasheet and see what voltage should be
                                3) U801 voltage regulator
                                4) U802 voltage regulator
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                                  #36
                                  Re: Dell E177FPf No Power

                                  1) D854 - seeing 25.4V on the middle leg.
                                  2) U851 Pin 1 - Voltage climbs very slowely from 0 to 0.882Vdc... and then stays there.
                                  2,3,4,5 all read 0V
                                  3) U801 All pins 0V
                                  4) U802 All pins 0V

                                  I haven't looked up the datasheet yet for Voltage reg, but I assume those readings to be bad.

                                  Comment

                                    #37
                                    Re: Dell E177FPf No Power

                                    Originally posted by billy66 View Post
                                    1) D854 - seeing 25.4V on the middle leg.
                                    25.4V DC could be right for this board. If the capacitors to the right of D854 are rated for 35V, then 25.4V DC sounds right. If the caps are rated for 25V, then I believe 25.4V is too high.

                                    PS. There might be another dual diode (that is obscured by the angle of the picture - above R860). It would be facing "up" on the same heat sink as D854. If yes, that should be your 5V diode.
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                                      #38
                                      Re: Dell E177FPf No Power

                                      Caps are 25V caps... And there isn't another diode on that same heat sink...

                                      Comment

                                        #39
                                        Re: Dell E177FPf No Power

                                        Originally posted by billy66 View Post
                                        Caps are 25V caps... And there isn't another diode on that same heat sink...
                                        I missed the comment in post #33 about the 16V DC being good in the other monitor and U850 showing 24V DC.

                                        Sounds like something wrong around that area. Will have to start with post #1 and re-read as I'm definitely getting confused with all the changes made.
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                                          #40
                                          Re: Dell E177FPf No Power

                                          Originally posted by billy66 View Post
                                          U850 pins 3 and 7 now have 24.8V steady (not sure if this is high. The known good monitor had 16Vs)
                                          Check diode D856 with your multimeter in diode check function and report the results for both diode measurements.
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