novice: dvd recorder capacitor

Discussion in 'General Electronics Chat' started by joetab24, Aug 26, 2011.

  1. joetab24

    Thread Starter New Member

    Aug 26, 2011
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    hi all,

    my dvd recroder stopped working recently. it was stuck on the opening screen with a message on the device saying "please wait".

    a quick google search revealed a # of posts about similar problems stemming from bad capacitors.

    i opened the player and quickly noticed one capacitor in particular was bulging at the top: http://tinyurl.com/3tjlfgs (not sure if you can see it in the pic) . i went to radio shack and was unable to get the exact capacitor. but I did get one with a larger voltage. I attempted to install it.

    i was also desoldering and soldering for the first time. when I couldn't get the device to do what it was doing initially with the new capacitor I proceeded to put back the old capacitor. Now I am unable to get the device to even power up.

    Now sure what to do next. Are there any tests I can do?

    Thanks!

    Joe
     
    Last edited: Aug 26, 2011
  2. debe

    Well-Known Member

    Sep 21, 2010
    946
    184
    Try some pics of the board from the top & the bottom.
     
  3. joetab24

    Thread Starter New Member

    Aug 26, 2011
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    0
  4. praondevou

    AAC Fanatic!

    Jul 9, 2011
    2,936
    488
    Replace the bulging capacitor. It doesn't look good and probably has lost capacitance.

    What DVD-recorder is it?

    I had a similar problem with a Sony rdr-hx717. The problem was a capacitor on the primary, not the secondary as in your case, though.

    To do some serious analysis you'll need an oscilloscope...

    However, I presume you don't have one, so you can at least check with a multimeter if you have voltage on the big 400V capacitor on the primary.

    BE CAREFUL! If you don't have experience I suggest you power up the device, then pull the plug and then measure the DC-voltage. If it's ok at least your input rectifier and fuse etc are ok, but if the capacitor holds it's voltage you also have a problem with the switching component/controller which I assume to be an 8-pin smd component on the bottom of the board.


    Check also if on any of the secondary side capacitors you have voltage while the device is plugged into mains. I suggest you isolate the primary side in a way that you cannot touch anything accidentaly.

    Be very careful when the recorder is plugged into mains, mains voltage can kill you. If you do any resistance/diode measurements make sure you discharge the primary side capacitor first via a resistor, otherwise you could hurt yourself or destroy your multimeter.

    Then, in my case, I got the thing back to work, BUT the HDD had some problem, I would have to restore part of the initialization files, which I had no access to, so the whole thing went to the trash bin. :D
     
  5. debe

    Well-Known Member

    Sep 21, 2010
    946
    184
    On the right hand side of the power T/F in the bottom pic you posted is a black plastic thing which probably has 4 legs. This is the primary switching device, probably a KA5L0380, or5LO380R. Heres a circuit of a simmilar board, the primary side is fairly standard on these units. This is the type of pictures that are easier to work with, this is out of a DVD player. The most likely problem will be most of the Caps are dried out & faulty. If you dont have an ESR meter to check them then replace the lot on the Secondary side. Bit hard to makeout parts on your board bit out of focus. Using the circuit shown here as as a sample. The IC1 is kick started by R9 , 56K 1W resistor to P3, if this is O/C it wont start @ switch on. C7, 47uf 50V is the cap for the IC1 power, if dried out may also cause poor start up. DO NOT Work on this when pluged in to the mains.
     
    Last edited: Aug 27, 2011
  6. joetab24

    Thread Starter New Member

    Aug 26, 2011
    3
    0
    thanks for taking a look and the detailed replies...


    "What DVD-recorder is it?" It is Panasonic (i'll have to check for the model #)


    Going to create a to do list from your suggestions....

    First, I need to get a multimeter. I'll check the forums for some suggestions on a good one to purchase.
     
  7. tom66

    Senior Member

    May 9, 2009
    2,613
    213
    Also I would advise against installing a cheap radioshack capacitor. They are not low ESR and will probably die after a year or so. For that player, I'd recommend Rubycon YXF or Panasonic FC (or FM), both are available from Digikey.

    Surprising Panasonic did not use their own capacitors in their DVD player, seems likely that it would have cost them more than to buy cheap crap ones from other sources.
     
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