Thank you to the guys at HEGE supporting Badcaps [ HEGE ] [ HEGE DEX Chart ]

Announcement

Collapse
No announcement yet.

Dell 1905FP Won't Turn On

Collapse
X
Collapse
 
  • Page of 4
  • Filter
  • Time
  • Show
Clear All
new posts
Previous 1 2 3 4 template Next
    #41
    Re: Dell 1905FP Won't Turn On

    Originally posted by ryszardx View Post
    Is there a value for on board testing - i.e. resistance unpowered in primary and secondary?
    Primaries should be 0.3 ohms. Secondaries will range from 250 to 1500 ohms depending on the transformer. Post your results and we can help interpret.
    --- begin sig file ---

    If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

    We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

    Please do not post inline and offsite as they slow down the loading of pages.

    --- end sig file ---

    Comment

      #42
      Re: Dell 1905FP Won't Turn On

      Originally posted by PlainBill View Post
      . Did you connect a full set of CCFLS?. If so, were they all the same brightness?

      I'm now suspecting a bad (arcing) transformer.

      PlainBill
      Have you tried what PlainBill sugested?
      If you don't have a ring tester you may be able to prove the coil as being a problem, by looking for a difference in the brightness of the flash of the backligts, on each individual transformer.
      Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

      Comment

        #43
        Re: Dell 1905FP Won't Turn On

        PlainBill I connected a full set they didn't stay on long enough but at what I could see they were equally bright

        Comment

          #44
          Re: Dell 1905FP Won't Turn On

          both transformers had the same results:
          @.5 ohms at the primary and @450 ohms at the secondary.

          Comment

            #45
            Re: Dell 1905FP Won't Turn On

            Originally posted by ryszardx View Post
            PlainBill I connected a full set they didn't stay on long enough but at what I could see they were equally bright
            Reading through other 1905 FP threads; one had an issue of bad solder joint at the back light on pin.
            Can you see if the BL on voltage stays the same when the lamps turn off?
            Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

            Comment

              #46
              Re: Dell 1905FP Won't Turn On

              Originally posted by ryszardx View Post
              both transformers had the same results:
              @.5 ohms at the primary and @450 ohms at the secondary.
              These readings suggest that the inverter transformer is likely good. However, I should point out that this test is not 100% accurate for reasons described by PlainBill at

              https://www.badcaps.net/forum/showpo...39&postcount=9
              --- begin sig file ---

              If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

              We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

              Please do not post inline and offsite as they slow down the loading of pages.

              --- end sig file ---

              Comment

                #47
                Re: Dell 1905FP Won't Turn On

                Excellent breakdown on inverter transformers!
                I noticed no one mentioned the 2 transistors in the inverter circuit. Are they discounted for whatever reason.

                Comment

                  #48
                  Re: Dell 1905FP Won't Turn On

                  Originally posted by ryszardx View Post
                  I noticed no one mentioned the 2 transistors in the inverter circuit. Are they discounted for whatever reason.
                  This thread is long overdue for some pictures. Please attach clear focused pictures of all your boards using the manage attachments feature. Please do not post inline.

                  Then we can see the 2 transistors in question.
                  Last edited by retiredcaps; 04-12-2011, 04:36 PM.
                  --- begin sig file ---

                  If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                  We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

                  Please do not post inline and offsite as they slow down the loading of pages.

                  --- end sig file ---

                  Comment

                    #49
                    Re: Dell 1905FP Won't Turn On

                    I uploaded a number of photos of the boards.
                    Attached Files

                    Comment

                      #50
                      Re: Dell 1905FP Won't Turn On

                      You have 4 transistors sandwiched in between the 2 transformers, but I can't make out the PCB designation because your photos are not clear enough.

                      They might be c5707s. You can test them "in circuit" without desoldering them for shorts. Measure the ohms between B-C, C-E, B-E. Any reading less than 30 ohms suggests a shorted transistor.
                      --- begin sig file ---

                      If you are new to this forum, we can help a lot more if you please post clear focused pictures (max resolution 2000x2000 and 2MB) of your boards using the manage attachments button so they are hosted here. Information and picture clarity compositions should look like this post.

                      We respectfully ask that you make some time and effort to read some of the guides available for basic troubleshooting. After you have read through them, then ask clarification questions or report your findings.

                      Please do not post inline and offsite as they slow down the loading of pages.

                      --- end sig file ---

                      Comment

                        #51
                        Re: Dell 1905FP Won't Turn On

                        They are 13n07 4c37e. I checked them in circuit and they check out >30 ohms.

                        Comment

                          #52
                          Re: Dell 1905FP Won't Turn On

                          Any more ideas to help get this monitor up and running!

                          Comment

                            #53
                            Re: Dell 1905FP Won't Turn On

                            Does anyone have a replacement IPS board for sale for the Dell 1905FP?

                            Comment

                              #54
                              Re: Dell 1905FP Won't Turn On

                              Originally posted by ryszardx View Post
                              They are 13n07 4c37e. I checked them in circuit and they check out >30 ohms.
                              What is the exact ohm reading you are reading on these transistors?
                              Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                              Comment

                                #55
                                Re: Dell 1905FP Won't Turn On

                                q105 - G-D =12M, G-S = 17.4M, D-S =10.8K
                                q106 - G-D =13.5M, G-S = 17.5M, D-S =12K
                                q107 - G-D =14.8M, G-S = 17.3M, D-S =10.7K
                                q108 - G-D =14M, G-S = 17M, D-S =10.7K

                                Comment

                                  #56
                                  Re: Dell 1905FP Won't Turn On

                                  Could you try to get a better picture of the bottom side of the Inv/PS
                                  Overall straight down without a flash, and more in focus?
                                  Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                                  Comment

                                    #57
                                    Re: Dell 1905FP Won't Turn On

                                    Here's a back and front of the board. The board was slightly tilted. I can reshoot if you need it. Ran out of time today. Thanks Rich

                                    Comment

                                      #58
                                      Re: Dell 1905FP Won't Turn On

                                      I am getting security token error uploading my photos. I'll try again tomorrow.

                                      Comment

                                        #59
                                        Re: Dell 1905FP Won't Turn On

                                        Originally posted by ryszardx View Post
                                        I am getting security token error uploading my photos. I'll try again tomorrow.
                                        If you have a really good camera, that's 10m or better you're going to into your camera settings and reduce it down to about 5m.Then with some type of photo editor reduce the picture down to 2000x2000 that should allow you to post pictures using managed attachments.
                                        Whatever I do, I consider it a success, if in the end I am breathing, seeing, feeling and hearing!

                                        Comment

                                          #60
                                          Re: Dell 1905FP Won't Turn On

                                          For a small footprint photo editor and viewer, Viewprint Pro is hard to beat. And the price is right - free.

                                          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

                                          Previous 1 2 3 4 template Next
                                          Working...
                                          X