HP no backlight

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  • jetadm123
    Badcaps Legend
    • Feb 2010
    • 2169

    #21
    Re: HP no backlight

    Ah, I misunderstood your initial voltage readings for on/off. Looks like the main board is sending the correct 3.24V to turn on the backlights. Disregard my initial comments regarding I308.

    Going back to Q104 and Q105. What voltage readings are you getting when you measure pin 3 (S1) on Q104 and Q105?

    Comment

    • davg
      Badcaps Veteran
      • Sep 2008
      • 536
      • Canada

      #22
      Re: HP no backlight

      Thanks jetadm123 Pin 3 (S1) Q104-Q105 both read 26.2v Black lead on ground screw red lead on pin 3, connected to running PC

      Comment

      • jetadm123
        Badcaps Legend
        • Feb 2010
        • 2169

        #23
        Re: HP no backlight

        Good. At least we know those transistors have access to power to perform their switching actions.

        In the top middle of your power supply photo:

        With power off and monitor unplugged, try checking transistors Q106 and Q107.

        With your meter set to 200 ohms, place your meter probes across:

        E-B
        B-C
        E-C

        Reverse your leads and perform the same checks again.

        You may have to set your meter to a higher resistance setting to see a valid reading.

        Comment

        • davg
          Badcaps Veteran
          • Sep 2008
          • 536
          • Canada

          #24
          Re: HP no backlight

          Q106 reading EB 51.7 k BC 151k EC 99k both ways Q107 EB 99.4k BC 16m EC 16m reversed EB 99.4k BC 16.5M EC 16m (meter set to auto)

          Comment

          • jetadm123
            Badcaps Legend
            • Feb 2010
            • 2169

            #25
            Re: HP no backlight

            Doesn't look like anything is shorted. Looks like we will have to move on to the ccfl controller, I101. Fortunately, it's only 8-pin. Measure the voltage at each pin. What's the part number of I101? Note: I have to run some errands and will be gone several hours.

            Comment

            • davg
              Badcaps Veteran
              • Sep 2008
              • 536
              • Canada

              #26
              Re: HP no backlight

              The markings on (I101) is Line 1- OZ9930D, Line 2- 43279731G Line 3- 0505A The voltage readings are as follows: With the indicator mark north and pin 1 immediate left and pin 8 immediate right Pin 1- 2.4v pin 2- 0.08v pin 3- 0.01v pin 4- 0.01v pin 5- 0.01 pin 6- 3.8 pin 7- 1.9v pin 8- 0.05v

              Comment

              • jetadm123
                Badcaps Legend
                • Feb 2010
                • 2169

                #27
                Re: HP no backlight

                I'm in a holding pattern right now because I can't seem to locate a data sheet for the OZ9930.

                Comment

                • davg
                  Badcaps Veteran
                  • Sep 2008
                  • 536
                  • Canada

                  #28
                  Re: HP no backlight

                  I have searched and can't seem to find one either. Closes I could find was OZ998 Thanks

                  Comment

                  • retiredcaps
                    Badcaps Legend
                    • Apr 2010
                    • 9271

                    #29
                    Re: HP no backlight

                    Originally posted by jetadm123
                    I'm in a holding pattern right now because I can't seem to locate a data sheet for the OZ9930.
                    https://www.badcaps.net/forum/showthread.php?t=8907

                    may help?
                    --- 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

                    • jetadm123
                      Badcaps Legend
                      • Feb 2010
                      • 2169

                      #30
                      Re: HP no backlight

                      Thanks retiredcaps. It does shed a little light on the subject by identifying which pin is which. Only problem is that we still don't what the minimum voltage(s) are required to make the OZ9930 run correctly.

                      Comment

                      • budm
                        Badcaps Legend
                        • Feb 2010
                        • 40746
                        • USA

                        #31
                        Re: HP no backlight

                        Did anyone find the place to download the spec sheet?
                        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

                        • davg
                          Badcaps Veteran
                          • Sep 2008
                          • 536
                          • Canada

                          #32
                          Re: HP no backlight

                          According to that drawing It would appear I should have 5v on pin 7 and I am recording 1.9? or is something else in that circuit effecting that voltage?

                          Comment

                          • retiredcaps
                            Badcaps Legend
                            • Apr 2010
                            • 9271

                            #33
                            Re: HP no backlight

                            VDDA, in other OZ9 datasheets, is typically 5V DC. If it is low, then it could be that the OZ9 pwm is some sort of protection mode (over voltage, open lamp protection).

                            I suggest measuring the secondary windings (in red and yellow) on the inverter transformers to see if open is open. Post your resistance measures for both colors.
                            Attached Files
                            Last edited by retiredcaps; 11-04-2012, 08:25 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

                            • budm
                              Badcaps Legend
                              • Feb 2010
                              • 40746
                              • USA

                              #34
                              Re: HP no backlight

                              OK, after looking through my HP pictures collections, this HP VS17 uses the same power supply/inverter board as VS19/D.
                              Here is the service manual, the sch seems to match your board. It also has good explanation how it works.
                              Attached Files
                              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

                              • davg
                                Badcaps Veteran
                                • Sep 2008
                                • 536
                                • Canada

                                #35
                                Re: HP no backlight

                                Thanks retiredcaps these two points are reading .458k and .454k
                                Thanks budm great information and will require much study. Great troubleshooting section. Don't put away your HP pictures yet because I have a HP f2105 that I have been trying to find a service manual for if I may be so bold??
                                Last edited by davg; 11-05-2012, 07:00 AM.

                                Comment

                                • jetadm123
                                  Badcaps Legend
                                  • Feb 2010
                                  • 2169

                                  #36
                                  Re: HP no backlight

                                  Thanks budm for the service manual, it helps a lot.

                                  davg- on the VS19 service manual, go to page 15 for troubleshooting the inverter circuit and try taking some of the recommended voltage measurements.

                                  Comment

                                  • budm
                                    Badcaps Legend
                                    • Feb 2010
                                    • 40746
                                    • USA

                                    #37
                                    Re: HP no backlight

                                    davg, I hope if you do not mind, I post your pictures of the boards on my Photobucket.
                                    By the way, the HP F2105 are know for having bad lamp assemblies and bad LCD panel (vertical lines), I had done 5 of them, all with bad lamp assemblies.
                                    http://s807.photobucket.com/albums/y...HP/HP%20F2105/
                                    Last edited by budm; 11-05-2012, 10:50 AM.
                                    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

                                    • davg
                                      Badcaps Veteran
                                      • Sep 2008
                                      • 536
                                      • Canada

                                      #38
                                      Re: HP no backlight

                                      Thanks jetadm123 I have been away but will get some readings as soon as I get back on track. Question on the trouble shooting page check voltage on pin C112 is that across the cap c112?
                                      Thanks budm truly appreciate it. This f2105 do have lines but they are shadows of the objects on the desktop and a very slow refresh rate. Takes the mouse for ever to move from one point to the other? I will start another thread on that one later
                                      Last edited by davg; 11-05-2012, 08:21 PM.

                                      Comment

                                      • jetadm123
                                        Badcaps Legend
                                        • Feb 2010
                                        • 2169

                                        #39
                                        Re: HP no backlight

                                        I see what you mean. Since they say "pin", it sounds more like a test point, but I'm not sure. However, I think most members agree it's an inverter problem and I would go on to the next step, checking pin 6 of I101. You read 3.8V versus the suggested 5V (I don't know what the min VDD is for the OZ9930). The flowchart says to check R105 and C112. I think it's a typo and they meant C102 instead of C112, since C112 is not part of the VDD circuit.
                                        Last edited by jetadm123; 11-06-2012, 01:08 PM.

                                        Comment

                                        • budm
                                          Badcaps Legend
                                          • Feb 2010
                                          • 40746
                                          • USA

                                          #40
                                          Re: HP no backlight

                                          Can I get the resistance reading of each pin of the PWM IC OZ9930 and Ground?
                                          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

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