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Replacing a capacitor in my DVD player

  1. Feb 28, 2015 #1
    A while ago my dvd player stopped working so I checked the board out and found the problem was a blown capacitor. The capacitor that blew out was of 1000μF10V I was able to find a replacement but the voltage is different its a 1000μF35V I was wondering if putting this new capacitor in would mess up my dvd player.
     
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  3. Feb 28, 2015 #2

    Averagesupernova

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    Once upon a time while I was in school I replaced a non-polarized electrolytic with a standard electrolytic not realizing the original was a non-polar. Lasted about day before it blew up. So watch out for that. Do you know what part of the circuit this is? I would assume the power supply? 5 volt supply maybe? A cap rated for 10 volts would not likely be on any other supply. Also seems unlikely a cap would blow out unless the power supply went out of regulation putting excess voltage across it. If your DVD player is messed up after you put the new cap in then I would say it was already messed up and took out the original cap.
     
  4. Mar 1, 2015 #3

    davenn

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    not necessarily and not often ... in fact its usually around the other way .... electro's in PSU's dry out and fail with monotonous regularity and that causes the PSU to start producing oddball output voltages and next to no smoothing. 99% of the time the failure is caused by overheating
    Over the years, replacing caps like that has given me much paying repair work :smile:

    no it wouldn't. the only thing that may be a problem is that the 35V rated one is likely to be physically much bigger and may or may not fit in where the blown one came from. Else you are good to go :smile:

    EDIT .... ohhh and make sure you use a 105 degree C temp rated one rather than a 86 degree C


    cheers
    Dave
     
  5. Mar 1, 2015 #4

    sophiecentaur

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    Be prepared for the capacitor replacement not to solve the problem. Consequential faults can occur in strings.
     
  6. Mar 1, 2015 #5

    jim hardy

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    the lazy man's test for open filter cap that died of old age in the heat is :
    place your dmm across it in circuit
    measure DC
    switch DMM to AC and you should read less than 10% of the DC value, in most circuits less than 5% .

    They die of old age usually looking just fine to the eye.
    If it physically blew its end out or vented its fluid all over the board be prepared to find more things wrong, as Sophie advised.
    Clean it up and try another one.
     
  7. Mar 1, 2015 #6
    Erm... no. If the cap is died of the 'badcap' plague, then most of the times a simple mechanical cleaning and replacement of the affected capacitors (always every one of the same type) solves the problem. Even if the top of the caps are broken and the electrolyte is out.
    (It's interesting that this kind of electrolyte is somehow not corrosive. A damaged battery can wreck a PCB even from some centimeters distance, but from the capacitor-kind of electrolyte - nothing.)
    By my experience it's when the sides of the cap are bent when time to look for real problems...
     
  8. Mar 1, 2015 #7

    jim hardy

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    i was thinking more of when a sudden overvoltage blows them apart.

    Indeed, the capacitor plague was fortuitous for some folks..
    son-in-law with no prior electronic experience picked a flatscreen TV out of the trash. Had a screen so so big i thought it must be a drive-in.....
    he replaced three "bulged" capacitors for under five bucks and it started right up.

    "Amen" on Dave's temperature recommendation.

    interesting reading from an old line capacitor manufacturer
    http://www.cde.com/resources/catalogs/AEappGUIDE.pdf
     
  9. Mar 1, 2015 #8

    davenn

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    ohhh, nice document there Jim, thanks for that .... hadn't seen before

    I didn't comment on ESR .... some seem to make a bigger deal out of it than I often feel needed
    If I was dealing with precision test/commercial electronics, I would definitely take ESR into consideration

    But honestly in domestic electronic repairs, TV, VCR audio amplifiers etc
    I have never worried about it, and I doubt the el'cheapo manufacturers in China have either LOL
    But I ALWAYS make sure (particularly in PSU's) that I use 105C caps rather than 85C ones

    Much of today's domestic electronics and particularly PSU's .... plugpacks, inline powerpacks for laptops etc
    have no ventilation and capacitor failure to overheating and drying out is really just a case of "when" rather than "if" it will happen

    signs of failed electro's can range from nothing obvious and a test as Jim described above will determine the faulty cap
    to very minor swelling of the top of the electro, to significant swelling/bursting of the top

    Jim, failing the multimeter test, did you ever do as I and many did .... just touch the solder points of the PCB under suspected caps
    with a good one ( with appropriate voltage and polarity observations) and watch the bit of equip burst into life ? :smile:.

    cheers
    Dave
     
  10. Mar 1, 2015 #9

    jim hardy

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    yes . Sometimes we'd tack-solder in a known capacitor and measure how much it reduced ripple. Then calculate what was the capacitance of the in-circuit capacitor....

    at work we had good Tektronix scopes on the bench and first thing we'd look at power was supply ripple.
    We noticed in one particular instrument model ( we had several hundred of that one) a correlation between needle-like kilohertz pulses from unijunction relaxation oscillators and short filter capacitor life. Never quite figured that one out. I will always think it had to do with absence of high frequency bypassing.

    It's important for industrial applications because it sets ripple current rating. I had the good fortune to participate in design for a replacement controller. I got aerospace grade tantalum, hang the expense .

    Sprague 600D is a high reliability aluminum but bulky.
    http://www.vishay.com/docs/42047/600d.pdf
     
    Last edited: Mar 1, 2015
  11. Mar 2, 2015 #10
    That's when the sides are also bent.

    The PSU in some modern equipment might require Low-ESR caps.
    Also, they are common on computer parts.
     
  12. Mar 2, 2015 #11

    davenn

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    as I said ... sometimes, but rarely for cheap Chinese made domestic stuff .... they don't give a rat's patootie how long it lasts
    Computers in general are in a different league, as they tend to be built for a harder commercial life
    and that is a benefit for the domestic user :)
     
  13. Mar 4, 2015 #12
    Thanks for the advice guys. The Dvd player(Panasonic) in question is about 10 years old now the capacitor blew out about a year ago. It didn't leak any fluid the top was only bulging. I didn't notice that the capacitor that I bought was only rated for 85°C I put it just to test the dvd player it worked I order a few new ones from amazon they are still higher voltage(25v) but with a 105°C rating. Hopefully nothing goes wrong. Do you guys have any advice for desoldering using a desoldering braid because I haven't soldered in a long time and it was a big hassle trying to get the old one out but still pretty fun.
     
  14. Mar 4, 2015 #13

    Averagesupernova

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    I have posted previously on this forum concerning soldering and desoldering. Do a search and you will come up with plenty of good stuff.
     
  15. Mar 5, 2015 #14

    jim hardy

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    Solder will follow the heat
    so lay the braid on the joint and put soldering iron tip on top of the braid not the joint
    and use a clean part of the braid to remove more solder.

    Too much heat and the pad will come off the board. Thirty watt iron is more than enough, don't use a "slaughtering gun" .

    When you can straighten the part's leads do so, and switch to heating the end of the lead 'til you have worried it free from pad..

    Search by member "Averagesupernova" keywords "soldering braid" returned no results for me... does search go back past recent software upgrade?
     
  16. Mar 5, 2015 #15
    Thanks will do. You were right by the way it was a cap on the power supply. I hadn't noticed until Sunday when I replaced it.
     
  17. Mar 5, 2015 #16
    I actually found what Nova was talking about by Searching by member "Averagesupernova" and keywords "Desoldering"
    https://www.physicsforums.com/threa...-components-from-a-board.699032/#post-4429580
    Thanks though Jim for the tips. Especially about the wattage of the soldering iron I didn't even check last time. My new capacitors are coming in today so hopefully I can try this out.
     
  18. Mar 5, 2015 #17

    jim hardy

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