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DELL E177FPb im ready for my first troubleshooting! need your help!

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    #21
    Re: DELL E177FPb im ready for my first troubleshooting! need your help!

    here are the hfe reading form the old and new parts i will try group 1 since the are all above 350! Let me know what you think!
    Attached Files

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      #22
      Re: DELL E177FPb im ready for my first troubleshooting! need your help!

      Did you check out the ccfls with a "good one" as per post #10? If you have a spare lcd, it is easy to do.
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        #23
        Re: DELL E177FPb im ready for my first troubleshooting! need your help!

        yes but i will try it again to be sure!

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          #24
          Re: DELL E177FPb im ready for my first troubleshooting! need your help!

          Originally posted by pr0cess0r View Post
          No result from replacing those parts. i will finish my recap even if those elite test ok i dont like theme ! its alays 2 sec to black i try ccfl one by one same result. is there a way to force the inverter to stay on and know if it can be one of the ic that is bad ?
          To make sure were all on the same page, are you sure you have what we call 2 sec to black?
          Can you identify the back light on signal and see if the voltage stays the same when the lamps go out?
          This is usually a voltage of some ware around 3 to 5 volts when the logic board is asking for back lights.
          Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

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            #25
            Re: DELL E177FPb im ready for my first troubleshooting! need your help!

            I remember hfe from my very early electronic theory lessons,but never in 35 years have I ever needed to use it in fault finding.

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              #26
              Re: DELL E177FPb im ready for my first troubleshooting! need your help!

              i dont know the pinout of the logic board but i will try to find a voltage that drop afther the 2 sec. i tested with a laptop ccfl and have the same result maybe its the logic board. I post back later!

              Comment

                #27
                Re: DELL E177FPb im ready for my first troubleshooting! need your help!

                Originally posted by pr0cess0r View Post
                i tested with a laptop ccfl and have the same result maybe its the logic board.
                Can you describe in detail how you did this test with the laptop ccfl? I'm not doubting your testing capabilities, but I just want to understand your test process. For example, here is a test procedure that I wrote (see #5)

                https://www.badcaps.net/forum/showpo...1&postcount=14
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                  #28
                  Re: DELL E177FPb im ready for my first troubleshooting! need your help!

                  no drop on any of the logic board pin. IC801 at pin 7 is at .86 volt then there is a peak at about 12v then the backlite turn off ...

                  Comment

                    #29
                    Re: DELL E177FPb im ready for my first troubleshooting! need your help!

                    ok i made the ccfl test like you describe and found that at cn803 or cn804 if i replace on of those 2 ccfl with the laptop one it stay on but its not a particuliar one both act the same. Thx for pointing out how to test this i whas testing them one by one and didnt know that it monitor if they are all connected !

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                      #30
                      Re: DELL E177FPb im ready for my first troubleshooting! need your help!

                      Originally posted by pr0cess0r View Post
                      ok i made the ccfl test like you describe and found that at cn803 or cn804 if i replace on of those 2 ccfl with the laptop one it stay on but its not a particuliar one both act the same.
                      At this point you can disassemble the ccfl housing that connect to CN803 and CN804 and see if there is some bad wire soldering. Again, sample pictures are provided in post #10.

                      If both ccfls are broken at CN803 and CN804, I don't know if it is economically feasible to replace both as this is a 17 inch monitor. Of course, the $$$ decision is yours to make.
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                        #31
                        Re: DELL E177FPb im ready for my first troubleshooting! need your help!

                        I forgot to mention that one other thing to try is to resolder all the inverter transformer pins (i.e. T801, T802, T803, and T804). Benq boards have problems with poor solder connections on all these transformers. It doesn't hurt to resolder and retest because these inverter transformers are providing the high voltage AC to power the ccfls.

                        edit: PlainBill also mentioned this in post #2. I don't know if you have done it or not.
                        Last edited by retiredcaps; 04-19-2011, 01:19 PM. Reason: PlainBill also mentioned this in post #2
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                          #32
                          Re: DELL E177FPb im ready for my first troubleshooting! need your help!

                          Originally posted by retiredcaps View Post
                          I forgot to mention that one other thing to try is to resolder all the inverter transformer pins (i.e. T801, T802, T803, and T804). Benq boards have problems with poor solder connections on all these transformers. It doesn't hurt to resolder and retest because these inverter transformers are providing the high voltage AC to power the ccfls.

                          edit: PlainBill also mentioned this in post #2. I don't know if you have done it or not.
                          There are two blue capacitors between the C5707 transistors re-solder these also
                          Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

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                            #33
                            Re: DELL E177FPb im ready for my first troubleshooting! need your help!

                            Originally posted by pr0cess0r View Post
                            Thx for pointing out how to test this i whas testing them one by one and didnt know that it monitor if they are all connected !
                            The inverter IC chip that controls the ccfl backlights is an "all or nothing" (in simple terms). Either all the ccfls work and the backlight comes on or nothing at all. So if one or more ccfls are bad, the backlight will not come on at all.

                            edit: PlainBill explains it more technically at

                            https://www.badcaps.net/forum/showpo...&postcount=113
                            Last edited by retiredcaps; 04-19-2011, 01:30 PM. Reason: edit: PlainBill explains it more technically at
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                              #34
                              Re: DELL E177FPb im ready for my first troubleshooting! need your help!

                              all resoldered. Not fixed.

                              there is 2 ccfl that are ok the 2 othersi habe to replace one of the 2 with a laptop ccfl to allow it to stay on wich one i raplace and the location its connected dosnt matter.

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                                #35
                                Re: DELL E177FPb im ready for my first troubleshooting! need your help!

                                I opened it all and found tha bad ccfl !

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                                  #36
                                  Re: DELL E177FPb im ready for my first troubleshooting! need your help!

                                  Originally posted by pr0cess0r View Post
                                  I opened it all and found tha bad ccfl !
                                  If you want to replace it, members here report good feedback when dealing with ccflwarehouse.com.

                                  They have a tutorial on how to replace a bad ccfl, but be aware that it requires a lot of patience and a delicate touch.

                                  http://www.ccflwarehouse.com/lasotu.html

                                  More than a few people have broken their new replacement by rushing the job or trying to "jam" it in. Another option might be to buy the entire "assembly".

                                  http://www.ccflwarehouse.com/harnessedlamps.html

                                  Alternatively, you can look on ebay for a replacement ccfl.
                                  Last edited by retiredcaps; 04-19-2011, 02:41 PM.
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                                    #37
                                    Re: DELL E177FPb im ready for my first troubleshooting! need your help!

                                    ebay is expensive!! thx foir all the help and sorry that i over looked ccfl trouble ! i dont know if i will finish the fix since its expensive for a 17 inch like you said but im happy that i did find what whas the trouble finaly!

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                                      #38
                                      Re: DELL E177FPb im ready for my first troubleshooting! need your help!

                                      Originally posted by pr0cess0r View Post
                                      ebay is expensive!! thx foir all the help and sorry that i over looked ccfl trouble ! i dont know if i will finish the fix since its expensive for a 17 inch like you said but im happy that i did find what whas the trouble finaly!
                                      Here is what I have done, Search you local Craig's list and find an advertised broken LCD if the panels broken even better. You will probably be able to salvage at least 2 good CCFLs, and some other good parts. You should be able to find these for under $10
                                      Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                                      Comment

                                        #39
                                        Re: DELL E177FPb im ready for my first troubleshooting! need your help!

                                        over here everybody is possesive about theyr garbages lol!

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