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Hannspree hf237 problems

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    #1

    Hannspree hf237 problems

    Hey all,

    I recently aquired a Hannspree hf237 monitor for free (trash) anyways its in great condition except when the you turn on the monitor it powers up, lights on, screen image appears, then its like the lights go off. when i angle the screen i can still see the image.
    Upon first researching this issue i heard about the capacitors failing, i found a kit on ebay for $13, got it today in the mail, swapped out all the caps, and still same issue.
    Researching this issue even more (me finding this awesome site) i read someone saying they had similar issues and said it was bad CCFL's. I have also read that it can be the inverter board....
    My bro and I tore the screen apart and removed the lights and with the screen disassembled, powered it all up, lights come on bright, then go out.
    If the lights were bad would they light up at all?

    and where can i find an inverter board?

    kinda having trouble finding parts...

    much thanks and any input greatly appreciated!
    Tags: None
    #2
    Re: Hannspree hf237 problems

    Originally posted by GSXRchris85 View Post
    My bro and I tore the screen apart and removed the lights and with the screen disassembled, powered it all up, lights come on bright, then go out.
    If the lights were bad would they light up at all?
    The pwm inverter chip operates as an "all or nothing". It turns on all the ccfls briefly then monitors the status. If one ccfl is bad, the pwm inverter chip shuts down all the ccfls.

    2 seconds to black is described in detail starting with post #19 at

    https://www.badcaps.net/forum/showthread.php?t=10419

    Likely candidates are

    a) bad caps
    b) bad ccfl
    c) bad ccfl wiring
    d) bad inverter transformer

    I suggest focusing on c) and d) following the guide.
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    Comment

      #3
      Re: Hannspree hf237 problems

      UPDATE:

      with screen fully disassembled we tested both pairs of CCFL's. the one pair lights up fine for 2 seconds, then out.

      the other pair, one light, lights up, and the other light is dead. and it makes buzzing noise.

      i will be adding pics of the boards and CCFL's

      Comment

        #4
        Re: Hannspree hf237 problems

        Originally posted by GSXRchris85 View Post
        the other pair, one light, lights up, and the other light is dead. and it makes buzzing noise.
        If you are lucky, maybe just the wiring is frayed and can resoldered back on. If the ccfl is actually broken, then you will need a replacement. Sample pictures of both are in the guide.
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        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.

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        Comment

          #5
          Re: Hannspree hf237 problems

          Update: Pix and vid!!
          Attached Files

          Comment

            #6
            Re: Hannspree hf237 problems

            Good clear focused pictures.

            To rule out the inverter transformers as being bad, you can swap top and bottom ccfl connectors and see if the same ccfl remains unlit.
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            Comment

              #7
              Re: Hannspree hf237 problems

              you tube vid of CCFL power up:


              http://www.youtube.com/watch?v=bdwct...ature=youtu.be

              Comment

                #8
                Re: Hannspree hf237 problems

                TY Retiredcaps,

                I just did the test you said, and my one good CCFL rack lights up good on both bulbs on both ccfl connections, and the other rack has the bulb out on both ccfl connections.

                Comment

                  #9
                  Re: Hannspree hf237 problems

                  in the video, turn up the volume! you can hear the one CCFL rack with a dead bulb buzz

                  Comment

                    #10
                    Re: Hannspree hf237 problems

                    Originally posted by GSXRchris85 View Post
                    and it makes buzzing noise.
                    That noise could be due arcing if the ccfl wiring is frayed. The wiring is underneath the silicon end caps. Again, pictures of what frayed wiring looks like is in the guide.
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                    Comment

                      #11
                      Re: Hannspree hf237 problems

                      UPDATE:


                      i just disassemebled an old samsung LCD monitor and it had the same CCFL connections as my hannspree, i connected the samsung to the hannspree power board and it stayed lighted up. while displaying an image on my hannspree LCD screen, and it stayed powered and light up. i think i just need new CCFL's....

                      Comment

                        #12
                        Re: Hannspree hf237 problems

                        It looks like you work has narrowed the fault down to a bad ccfl or connector. I have just fixed one with exactly the same issue. You need to take the ccfl apart keeping the silicon cap and reconnect the wire onto the end of the ccfl.

                        Retired caps has given you some links for bad ccfls look at them so you know what your looking for.
                        Fixed so far : 1 Home cinema system, 16 LCD Monitors, 4 LCD TV's

                        How to resize your pictures guide click HERE
                        Retiredcaps Ideal post example click HERE

                        Comment

                          #13
                          Re: Hannspree hf237 problems

                          hey guys. i have had my Hannspree HF237 for nearly 4 yrs now. and just few days ago i have had this problem. i think its due to sandy and a power outage we had 5 days after. the power dipped and went, came back diped and went again and stayed off.... now the problem with the monitor is this, it would come on and stay on fine. but say i leave my computer on over night and the turn monitor off thing is enabled. i have it set for 45 mins. so in the morning i would see the orange light, move the mouse and the blue light would show for a sec or so and then i would hear a pop in the speaker every second and ever time it would get softer, while the pop is happening the blue light would come on and get dimmer till the sound and light go off. then it would take like 5 mins for the monitor to come on. when it comes on it stays on and works fine. any ideas?

                          Comment

                            #14
                            Re: Hannspree hf237 problems

                            This is all writtn in the past tense. Are you saying that before the power out the monitor worked fine and came on straight away when you moved the mouse and what you describe is what it does since the power out and now?
                            Sounds like it is deteriorating caps you will need to open it up and take pictures.
                            You may be able to spot faulty caps - bulged or leaking.
                            Try the hairdryer test - have it all set up and gently heat parts of the boards with the dryer to see if it comes on quicker - this can sometimes pinpoint the problem.
                            Welcome to the forum-
                            We can help a lot more if you please post good clear pictures of the whole chassis, and then pictures of each board, front and back and close up of connectors, (max resolution 2000x2000 and 2MB) using the manage attachments button, which is found by clicking "go advanced" under quick reply.

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

                            Examples of what is needed
                            https://www.badcaps.net/forum/attach...1&d=1290283049

                            https://www.badcaps.net/forum/attach...7&d=1280167246

                            It will be useful if you can say what the supposed fault was and a bit about yourself - skills tools etc.
                            Please upload pictures using attachment function when ask for help on the repair
                            http://www.badcaps.net/forum/showthread.php?t=39740

                            Comment

                              #15
                              Re: Hannspree hf237 problems

                              yes, if i move the mouse right after windows turns off the monitor there is no problem, if some time passes, then the stated problem occurs. so ill do the pictures.

                              Comment

                                #16
                                Re: Hannspree hf237 problems

                                ok i took the pictures, i hope they are good enough. just today the power went again and its totally not coming on this time.
                                Attached Files

                                Comment

                                  #17
                                  Re: Hannspree hf237 problems

                                  Looks like you have a lot of bulged capacitors on the power supply board. With the exception of the large 450V cap, you should replace them all with something like Panasonic FR/FM/FC series caps. I counted 9 caps.
                                  Last edited by jetadm123; 11-24-2012, 02:55 PM.

                                  Comment

                                    #18
                                    Re: Hannspree hf237 problems

                                    ^^^^^ I second that suggestion ^^^^^^
                                    Please upload pictures using attachment function when ask for help on the repair
                                    http://www.badcaps.net/forum/showthread.php?t=39740

                                    Comment

                                      #19
                                      Re: Hannspree hf237 problems

                                      9 caps in all or 9 caps that need replacing? and where would i find those caps? any suggestions?

                                      Comment

                                        #20
                                        Re: Hannspree hf237 problems

                                        Here is a clue for the 25v1000uf cap BUT you will need to check the height and diameter of the caps you have and get the same or smaller

                                        http://www.digikey.com/scripts/dksea...=20823&stock=1

                                        That is for FR series if they dont have FR in the size look at FM then FC


                                        You can also get caps from Badcaps.Net ( usually deals in motherboard caps so may not have the values you need.
                                        Last edited by selldoor; 11-24-2012, 04:01 PM.
                                        Please upload pictures using attachment function when ask for help on the repair
                                        http://www.badcaps.net/forum/showthread.php?t=39740

                                        Comment

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