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EMPREX LM1905 Screen Repair

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    EMPREX LM1905 Screen Repair

    Hi, and I hope i'm putting this in the right part of the site, please shuffle it around if i've made a mistake

    An EMPREX TFT screen came to me for repair, so I'm hoping this info will help somebody, it was a straight forward fix, but may help somebody with several models of the same design.

    The screen was doing the usual thing, of switching on for a few seconds, then off again. The display never lit up at all, though the power light came on green for the 2 seconds, then back to yellow for Stand-By mode

    On most of the screens I get to fix, I start by replacing the screens flat data cable with a known testing one I have. But on this screen, that didn't help, so I examined the circuit instead.

    A group of 4 caps grabbed my attention. I've shown them in a photo attached here, I hope it makes it clear. Another photo shows the 4 caps once removed. There's very little sign on a problem, except one shows a leak at the top vent. Even close up, none actually show a break in the vent as its that slight, but all 4 are bulging just a little.

    I replaced all 4 as they only cost about 80p each, and it's completely fixed the display. Here is the details on the replaced components:

    Original Caps:-
    2 larger caps are 680uf 25volt 105 degrees C, made my Su'scon and labelled
    with 0805(M) on them.
    2 smaller caps are 1000uf 10volt 105 degrees C, made by Su'scon and labelled 0803(M).

    The replacement ones are:-

    Low ESR type, 680uf 25v KZH with no manufacturer name on, and labelled with (M) 105c 0(7) 3Z

    Low Impedance type, 1000uf 10v -4-+105c and a name lable written in gold on black that I can't read It looks like a fancy company logo.


    I hope that info is of use to somebody out there

    In the photos i've included, it shows both the power board and logic board of the screen I fixed, there are many variations though generally it's just things being shuffled around the boards. Other photos are a close-up of the caps that I replaced, a photo of the 4 old ones I removed (showing slight bulging and a leak on one).
    Attached Files

    #2
    Re: EMPREX LM1905 Screen Repair

    Um... I see several other obviously bulging capacitors.
    Did you replace those as well?

    Comment


      #3
      Re: EMPREX LM1905 Screen Repair

      Originally posted by shovenose View Post
      Um... I see several other obviously bulging capacitors.
      Did you replace those as well?

      Those to the right of the photo are still on there way to me by post from a different supplier, hopefully they will appear tomorrow.

      I've replaced the others in sequence of the larger caps (still faulty), then the 2 smaller ones (fixed, yippee), and was a bit eager to let others know.

      Looks like that side of the board has a whole load of dodgy components?

      Thanks for noting that though Shovenose, I should have mentioned it in my original message. I shouldn't type at 3am

      Comment


        #4
        Re: EMPREX LM1905 Screen Repair

        Originally posted by filesponge View Post
        Low ESR type, 680uf 25v KZH with no manufacturer name on, and labelled with (M) 105c 0(7) 3Z
        The brown caps are United Chemi-con. They have a "crown" symbol on the sleeve and a Mercedez Benz or "Y" vent.

        As for just replacing the bulged caps, see my standard answer (regulars may skip) below.

        https://www.badcaps.net/forum/showpo...84&postcount=3
        Last edited by retiredcaps; 01-23-2012, 09:36 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


          #5
          Re: EMPREX LM1905 Screen Repair

          Originally posted by filesponge View Post
          I shouldn't type at 3am
          We've all done that at one point or another....

          Comment


            #6
            Re: EMPREX LM1905 Screen Repair

            Quick response before I retire for the night (why my days end between 3 and 4am is beyond me lol).

            Shovenose - glad i'm not the only one :-)

            Retiredcaps - Thanks for that information and quick response. And yes, i agree, if it was a repair for my own use i'd be replacing all parts I'd even suspect of misbehaving. But this is for another of my private customers with a middle man involved

            I do prefer to fix things properly, but the screen was due back to its owner today so no time was left to order any further caps. I have such impatient middle-men arranging the repairs I do. How can a person have a deadline on a repair ? lol

            Luckily, I just love the work over the wages & odd thinking of the guys bringing me some of these jobs.

            I'll see what tomorrow brings, probably several more Su'scon devastated caps no doubt, seems to be the main make I have on my desk at the moment.

            Comment

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