Announcement

Collapse
No announcement yet.

sharp lc32sb24u bulb / inverter problem

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    sharp lc32sb24u bulb / inverter problem

    I picked up this sharp lc-32sb24u and it has a flashing green light seems to be an even pace of 1 flash per second. Holding down the input and volume down while plugging it in resets the error and it will start and run for about 3 seconds.

    I consulted the manual for this model which says to just read the manual for lc-32d44u. So in that manual it says that 1 green light flash is an error with the bulb.

    Normally after knowing the bulb / inverters are probably the issue i would see if i could disconect each bulb seperately and test the tv with 1 disconected at a time, but if you look at the picture of this unit the inverter is screwed directly into connectors for the bulbs, so im not sure if there is any easy way to disconect 1 at a time.

    Second thing to check is if the windings have the same resistance on each inverter, which im going to try and check, but im not sur eif the secondarys have any exposed pins considering the way they go through the bottom of the board and connect straight to the bulb connectors.
    Attached Files
    Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

    #2
    Re: sharp lc32sb24u bulb / inverter problem

    Well actually i just looked at it, to try to test the inverters, and they are infact quite easy to get to, since they are the spools of copper wire next to the black connectors.

    So there are 5 inverters, at first when i measured the secondaries all were around 2.58 kohm, although one is 2.65 so slightly above the rest. But then after testign the primaries (which all have around 0.5 ohms resistance) i retested the secondaries and the bottom most inverter reads open. Occasionally id get a few seconds of a reading, but no matter how good of a connection i tried to make i couldnt get it to consistently read 2.58 ohms. So im guessing the problem is with that inverter.

    I tried flexing (the board has a LOT of flex ability) the board so that it wouldnt be connected to the bottom bulb, but all times i try it like that the tv wont clear the flashing green error, so i guess it isnt dumb enough to start with a bulb unplugged.

    So what do yall think? Bad inverter?

    Oh also, ive never worked on bulb inverters before, so im not sure if im choosign the right places to read the windings from, but these ones have 5 poles on each side of each transformer. when i measure the primary poles 1, and 2 on the top, and 1 and 2 on the bottom are all 0.5 ohms from each other. Poles 3 on top and bottom, are open to all the other poles so i think are not being used. Pole 5 on top and bottom is where i measured the secondardy on each one and got 2.58 kohms on most.
    Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

    Comment


      #3
      Re: sharp lc32sb24u bulb / inverter problem

      Can we see closed up pictures of the transformer top of the board and bottom of the board?
      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


        #4
        Re: sharp lc32sb24u bulb / inverter problem

        Yep here are some pics, tell me if other would help.

        I numbered the pins from left to right when looking at the front of the board (yellow side). And just from looking at the backside i can see now that the pin 3 is neither the primary nor the secondary but appears to have some sort of management function, as well as pin 4 appears to possibly be what monitors the ouput and reports the bulb failures.

        Pins 5 (top and bottom), which i was testing as the secondary, are what i got 2.58 kohms for all but the 1 that for the most part is open.

        And pins 1, 2 on top and bottom of each have 0.5 ohms (so almost no resistance) (i tested 1 top to 1 bottom, 1 top to 2 bottom, 1 top to 2 top and all were the same )
        Attached Files
        Last edited by cashkennedy; 03-29-2012, 09:08 PM.
        Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

        Comment


          #5
          Re: sharp lc32sb24u bulb / inverter problem

          Any idea where to look for a replacement transformer / inverter like the one in the picture (z1358 08086).

          Theres a almost exact match for the whole power inverter board for 19.99 on ebay, so i might just check if that guys board has the right inverters. (The cheapest exact match for the power inverter board is 60 though and from a bad seller)
          Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

          Comment


            #6
            Re: sharp lc32sb24u bulb / inverter problem

            Try www.lcdparts.net, but if you can get the new board for $20, that will be a lot better to have spare transformers and other parts. One transformer plus shipping will be $12~20.
            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


              #7
              Re: sharp lc32sb24u bulb / inverter problem

              Originally posted by budm View Post
              Try www.lcdparts.net, but if you can get the new board for $20, that will be a lot better to have spare transformers and other parts. One transformer plus shipping will be $12~20.
              We had one member buy an entire inverter board (iirc, around $20) just to get 2 replacement transformers because it was cheaper than buying 2 separate transformers ($24.99 each) from other vendors.
              --- 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


                #8
                Re: sharp lc32sb24u bulb / inverter problem

                I received the used / non working similar inverter and it did infact have the same transformers (it appears every sharp for like a year used basically the same mainboard and very similar power supply / inverter layouts.

                I realized the bad transformer just had the winding broken off at the pin, so fixed my existing transformer and it tested as 2.68 kohm, which is a tiny bit high but within 4% of the others now. So i didnt really need to buy the other inverter from ebay.

                Anyway it didnt work still after fixing that. As a recap after a error reset the screen comes on for 2 seconds and i can see the channel 2 display at top. Then it turns off and flashes a green light once per second (which means inverter problems).

                My current question : Im trying to test the DC/AC IC that controls the FET's for the backlight (it might also control the error reporting?). The part number was melted on the one on my existing board (not a good sign), so luckily i had the other board to read the part number off of, and it is BD9883.
                http://www.alldatasheet.com/datashee.../BD9883AF.html
                Is there any good method to test this IC? I did verify that all the pins went to the parts described and all seem to have good contact and go where they are meant to go.

                As a side note, with the other "untested / not working" inverter, it doesnt turn on the backlights and just flashes 2 green lights (some other error)
                Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

                Comment


                  #9
                  Re: sharp lc32sb24u bulb / inverter problem

                  Ive attached 3 pictures. The first is a view of the whole back of the board. The largest IC with 3 pins a regulator, the 10 pin is the AC/DC converter IC, and im not sure what the small IC does. The design of this inverter doesnt lend itself to testing very well since all the transformers are in parallel.

                  There are 2 groups of 2 FETS which provide the 2 AC inputs for the transformers and each group is gated by the AC/DC IC. The FET's appear to convert 13v power to the AC voltage. I have tried testing the AC voltage while the TV is on (for about 5 seconds), but do not get any readings. But the TV does light up, so obviously its an error in how im trying to measure it.

                  I also included a picture of the connector, because im wondering if theres any way to fool the err pin? (I assume its what reports the error to the main board), Like would cutting the wire work, or does the err pin transmit a steady voltage to the main board to prove everything is working.
                  Attached Files
                  Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

                  Comment


                    #10
                    Re: sharp lc32sb24u bulb / inverter problem

                    Do those error pins, or OFL/OSC show any change in voltage after ~2 secs?
                    Please do not PM me with questions! Questions via PM will not be answered. Post on the forums instead!
                    For service manual, schematic, boardview (board view), datasheet, cad - use our search.

                    Comment


                      #11
                      Re: sharp lc32sb24u bulb / inverter problem

                      Well the whole wrench in this damn problem is that the board has to be 100% in place (since the bulbs connect into the sockets on the side of the board.)... So i have no way to test it with the board loose, and the 10 pin IC is on the backside of the board. I guess i could test the err pin on the connector though ... gonna go see what it shows now.
                      Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

                      Comment


                        #12
                        Re: sharp lc32sb24u bulb / inverter problem

                        BTW: there are only 6 wires going to that connector i pictured. REG / OSC / BRT are not there (no wires ran to them, although they probably connect to something on the board).

                        When i measured the err pin it was around 2.7v till the backlight came on then it went to 0v and stays at that even after the set turns off and starts reporting the error code.
                        Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

                        Comment


                          #13
                          Re: sharp lc32sb24u bulb / inverter problem

                          Out of curiosity I did some more testing using the "not working/ untested" board i bought, and it is truely not working , its only outputting 1.2v or so on the 13v rail, the 5v appears to be running correctly at 5v though.

                          I tested the big caps (2 in series), and get 290v that quickly trickles down to 110v. Also the bridge has only 110v across its dc pins usually. and the AC pins i get almost no reading on, which is odd, but i do get 110v at where the plug attaches to the board.

                          Im pretty sure the original board i had was a active pfc board (cause of the extra transformer completly in the primary side), but the board i bought for parts and is not working has 2 large dc caps vs 1, and no transformer completely in the primary side. What should i be expecting for voltages on the caps / bridge assuming this model must be a high efficiency model that steps up the AC (there are some transfromers with huge copper wire on the bottom left that i assume are for stepping up the power before it enters the bridge rec. )
                          What would yall test next on the board with the bad 12v rail?
                          Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

                          Comment


                            #14
                            Re: sharp lc32sb24u bulb / inverter problem

                            On 1 board there is AC comming in it passes through inductors then goes to bridge , dc ouput goes through main dc cap, then dc is given to both the 13v and 5v transformer, and the 13v has a relay in the way.

                            On the parts board the AC comes in then goes through inducors then a relay, the neutral AC wire is ignored for now, after the relay the hot wire is ran to both AC pins of the bridge rec, the bridge rec then has its outputs run to both sides of the 2 dc caps in series, and their inner pins on the 2 caps in series are run to the AC neutral ... as a side note on this power supply the AC before the relay is seperated off into a manual bridge rec (4 physical diodes in pairs going opposite directions ... ) which leads to the 5v.

                            What exactly is the advantage of these 2 designs??? The second one seems totaly crazy, to build your own bridge rec out of diodes ...
                            Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

                            Comment


                              #15
                              Re: sharp lc32sb24u bulb / inverter problem

                              Well, i officialy wasted a bunch of time.

                              Note to self: never forget to return to the normal error checking path >

                              if you have a 2 second to black
                              1) check inverter transformers
                              2) check bulbs


                              ... once i fixed the transformer that i had damaged when testing i spend 2 days testing every component on the board ... when all i needed to do was check the bulbs. Sure enough 1 of them is bad. And since theres 2 bulbs in a row for each transformer, i can be certain its just the bulb and not the transformer.


                              So where do i order bulbs? the service manual luckily gives a list of all the stats it needs ... 1700v, 150hz or something,

                              Oh and additionally, i will give sharp credit for this being an awesome frame design for the screen. The lcd is attached to the outer metal frame, so you dont have to worry about the loose floppy screen cracking, its like taking the lid of a jar, it fits perfectly snugly over the light box.
                              Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

                              Comment


                                #16
                                Re: sharp lc32sb24u bulb / inverter problem

                                You can try lcdparts.net
                                Does the bulb has any sign of bad indication like blackened ends, pinkish glows?
                                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


                                  #17
                                  Re: sharp lc32sb24u bulb / inverter problem

                                  No it didnt really seem to be any worse then the others (they all have a little bit of black near the edges, maybe 3 mm worth or so).

                                  But since they are in series with another bulb and all the other bulbs are working i figured it was pretty likely that it is passing energy, just not starting. So I would assume it has a good connection and is receiving the proper current.

                                  Earlier when i was getting annoyed at the unit i adjusted a rotating switch that had 1 - 0 - 3 marked on it and it was at 0 to begin with, i set it to 0 and could hear a flickering crackle from the center of the light box (approximately where the bab bulb is), then i tried 3 and it was no different then 0)
                                  Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

                                  Comment


                                    #18
                                    Re: sharp lc32sb24u bulb / inverter problem

                                    I have never seen the bulb in series connection used in the TV LCD panel, each one is driven by the dedicated winding of the transformer, the the other end of the lamps should return to ground through a sensing network to tell the inverter IC if the lamp is fired up and stays conducting or if it draws too much current so the protection circuits will kick in.
                                    You may want to check the cold side of the lamp assembly.
                                    Attached Files
                                    Last edited by budm; 04-12-2012, 10:03 PM.
                                    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


                                      #19
                                      Re: sharp lc32sb24u bulb / inverter problem

                                      I will double check when im infront of the TV again, but the wiring diagram clearly shows the transformers (there are 5) have 2 windings a positive and negative winding which each are connected to 1 bulb (there are 10 bulbs) and then on the other end of the bulbs theres a small crude board (which i didnt examine very cloesly, but might connect them to ground. There is deffinetly no way for them to be monitored where they are grounded, if they are grounded at 1 end.

                                      What is your concern? because i tested all the secondary windings quite in detail and they are identical on all 5 transformers. specifically there are 4 pins on each transformer's secondary (2 per winding). And so if i number them as the service manual does with 7 and 8 on 1 windings and 9 and 10 on the other winding, and 8 and 9 are the pins that go to the bulbs, while 7 and 10 are connected by resistors and are what feeds into the monitoring parts.

                                      measuring 9-10 and 7-8 i get 500 ohms, and 7-10 i get 1500 ohms, and 8 - 9 (bulb to bull) i get 2500 ohms (the sum of the other 3). I get that for all 5 transformers.

                                      I could try swapping 2 bulbs and see if the one that doesnt light continue to be in the same place, or moves with the bulb. Also it would be very hard for me to notice a pink issue with the bulb when they only turn on for 2 seconds each time i reset the errors, and with all the other working bulbs around it.

                                      I think ill order a bulb from http://www.ccflwarehouse.com/ as they seem to have cheaper shipping and many more lengths / sizes then lcdparts. Neither lists the start voltages for the bulbs though which doesnt seem a good sign.
                                      Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

                                      Comment


                                        #20
                                        Re: sharp lc32sb24u bulb / inverter problem

                                        Attached is the page from the manual where they show the bulb connectors are + and - .
                                        Attached Files
                                        Fixed so far 12 lcd's , 1 plasmas, 5 monitors, 0 dlp's (plan to keep the dlps at 0). and 3 atx power supplies, and 2 motherboards.

                                        Comment

                                        Working...
                                        X