Sanyo Dp42740. any hope of fixing this?

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  • lllllllBOB
    Member
    • Jun 2004
    • 28
    • USA

    #1

    Sanyo Dp42740. any hope of fixing this?

    Sanyo DP42740.

    * Problem:
    When plugging it in.. it makes a few clicks.. and a short whining sound.
    - No power light at all. tv will do nothing else.

    * Reason:
    Was knocked off of stand onto the floor. was caught half way. but still hit the floor.
    - and while falling.. the cord was yanked unplugged from the back of the tv while on.
    - Nothing is physically broken. screen looks good. boards looks good. no cracks.
    (My uncle gave this tv to me. his son knocked it over. not me. lol)

    * What I do see:
    - 3 bad looking caps. not horrible looking.. but the're kind of buldging a tad bit.
    - and 1 of the 3 did not seem to charge up much at all when testing using an ohm meter.
    (2 250v 220uf and 1 1000 uf 80v. the 1000uf is the one that didn't test out good.)

    * So my question is..
    Would the fall and the cord being yanked out while on.. finish off the failing caps?
    Or would you say it was something else that may have broken in the fall?

    I would have just went straight for those bad looking caps had the tv just stop working on it's on and had not been in a fall to the floor. huhuh..

    I unplugged the x and y.. and it still clicked. So that says.. it's either the power board.. or maybe the video inputs board? Sorry.. I haven't worked on a flat screen tv before.
    yeh i know.. be carefull. checked the diodes.. seem good. one on the back of power board as well.
    and of course.. the 3 fuses are good too. dang it.. it's never the fuse for me lol

    I usually just fix pc mother boards and stuff like that with bad caps or something.
    I'll search around the junk pile later and see if I can find a 1000uf 80v cap out of something. would be nice if that would fix it.

    What's the usually way of testing voltages on this model?
    .. or will it have voltage to the x/y plug in's if it's not kicking on.

    well.. thanks for any info you may give.

    Hmm: I just thought of something after reading my own words lol..
    Maybe that whining sound is from the bad cap trying to power up?
    I'll have to re connect everything later and listen real closely near that cap.
  • martino
    Not so "senior"
    • Aug 2013
    • 997
    • canada

    #2
    Re: Sanyo Dp42740. any hope of fixing this?

    Either the already bad caps gave up completely now(passed threshold),or more likely while falling,the shock shorted the panel out for a quick sec and blew a buffer board or the y main. (seen it before where an object gets thrown at the screen,doesn't crack it but the impact shorted the screen out.)
    I would measure the Vs and Va and see if they come up at all,if not,unplug the y main and zsus and measure at power supply again while turning on tv,see if they come up then.
    Voltmeter on DC volt,expect a good 200 volt!,Black probe on back of chassis,red probe on the Va and then the Vs.
    Proud owner of dozens of broken TV's and many,many,many boards.


    Our website and passion:http://hollenhundshepherds.com/

    Comment

    • lllllllBOB
      Member
      • Jun 2004
      • 28
      • USA

      #3
      Re: Sanyo Dp42740. any hope of fixing this?

      Thanks for the reply man.

      Update: :-( nevermind on the power board. or pfft it could be that as well.

      While the screen itself is still not Broken as far as I can see. and after re-checking again....
      ---> There's a nick in one of the flex cables coming from the screen. Ouch. :-/ dang....
      ... the small nick appears to have severed the very outer connection on the cable.

      ---> Would that too give a no power light and no standby light? i'm guessing it will.

      .... nick was is in the curve part of the cable.. as it curves around... I barely even noticed it.
      and didn't even notice it the other hundred times i looked everything over. really small nick.
      and after looking at it a ton.. the connection is indeed severed on the outer strip. booo! lol

      Must have been caused by the fall I guess.. I hate ribbon cables! Wires please. :-/
      I'd rather have a big bundle of wires and it cost more.. than have flex cables... uhgg...

      * And I know how easy it is to fix a broken flex cable. Not very, and mostly if at all. huhuh...
      .. but possible. sometimes.

      Since it is the very outer connection.. I will try to rig something up....
      ..sure won't hurt nuthin. for it don't work anyway.. and it was free.
      Had it been any farther than that outer connection.. I'd say it would be totally non-fixable.
      They could have had connectors on both ends.. and not one end made into the screen.
      ... and thus.. I could have just bought a 4inch long new cable. :-/ stupid tv sanyo makers.

      I will first.. scrape it to the copper with a scalpel very very carefully..
      ...trying not to damage the next needle size connection strip.....uhgg...
      and then use some solder paste or something like that? Any suggestions on paste?
      or foil tape.. or aliminum foil glued over it. lol :-D for it just needs to make a connection.
      ..yeah.. some solder paste.. and then some conductor tape on top.. yup.

      and I know.. don't even try to hot solder no flex cable.. unless it's has really wide connection strips...
      and this one does not. needle size strips on this. jeeeez. ouch. real tiny...

      I would bet money.. if I do fix this cable.. the tv will still not work. lol! it will be sumn else too.

      I Will update this post if i manage to rig up that cable...

      But either way.. I knew the Fall.. should have damaged something.. Hope that's the only thing.

      Comment

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