Wima MP3-X2 failed in AC line filter

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • japlytic
    Badcaps Legend
    • Oct 2005
    • 2085
    • Australia

    #1

    Wima MP3-X2 failed in AC line filter

    Over a week ago, there was a strange smell in the house when the heater was running (the line filter was connected to the TV and other equipment, along with the heater - it was not overloaded). Yesterday, the 10A fuse in the line filter blew and upon opening it, a Wima MP3-X2 0.047uF capacitor was leaking, and tests shown it had electrical leakage.
    This capacitor was apparently under stress, causing it to heat up and eventually started to short when it overheated.
    My first choice in quality Japanese electrolytics is Nippon Chemi-Con, which has been in business since 1931... the quality of electronics is dependent on the quality of the electrolytics.
  • PeteS in CA
    Badcaps Legend
    • Aug 2005
    • 3576
    • USA, Unsure of Planet

    #2
    Re: Wima MP3-X2 failed in AC line filter

    The failure mechanism probably was something like this. Whether due to weak spots or voltage surges, arcing occurred at multiuple locations over time. While metallized caps "self-heal", there is residual carbon at the location of the arc, a high resistance current path. Each of these arc locations generates a certain amount of heat, and as the number of arc locations increases over time, the generated heat increases, eventually leading to overheating a dramatic failure. This has been a known failure mode with X caps for some 20 years that I'm aware of.

    Was this a metallized film or metallized paper cap? BTW, Wima makes good film and paper caps, so this wasn't the film/paper equivalent of crap caps.
    PeteS in CA

    Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells.
    ****************************
    To kill personal responsibility, initiative or success, punish it by taxing it. To encourage irresponsibility, improvidence, dependence and failure, reward it by subsidizing it.
    ****************************

    Comment

    • starfury1
      Badcaps Legend
      • May 2006
      • 1256

      #3
      Re: Wima MP3-X2 failed in AC line filter

      Thought id really leave this to somebody who knows

      I wouldn't think a current overload would take out one of these caps anyway
      but I could be wrong

      Given the weather conditions we have been having lately and your location Japlytic
      well could be a lot more spikes etc on the mains...

      Just out of curiosity what type of heater is it ?
      one that cycles on and off or the old wire wound power resistor

      wouldn't really have a clue here
      But just wondering if maybe some switching action maybe generating spikes

      Anyway here a link to a PDF on that cap type mp 3 x2 pdf

      HTH Cheers
      You step into the Road, and if you don't keep your feet, there is no knowing where you may be swept off to." Bilbo Baggins ...

      Comment

      • gonzo0815
        Badcaps Legend
        • Feb 2006
        • 1600

        #4
        Re: Wima MP3-X2 failed in AC line filter

        Those Wima caps are usually really robust, so i think normal electrical stress should not cause any harm to them, at least not beyond the self healing capability.

        I think PeteS has already described the failure mode for this kind of cap more than correct.
        I have seen this problems in many TV Focus boards too, where the FKP1 6000v caps are used, two in series to get a healthy 12kv device.
        But unfortunately, the cold soler joints, the resulting heat and smear will kill them too.

        Comment

        • japlytic
          Badcaps Legend
          • Oct 2005
          • 2085
          • Australia

          #5
          Re: Wima MP3-X2 failed in AC line filter

          Here is a picture of the failed cap.
          Note the split on the top, which was caused by pressure building up when the capacitor started heating up, causing the impregnation material to melt and subsequently leak through this split.
          This capacitor reminds me of the AEE Miniprint capacitors, which were once used in the speed control of Mistral Gyro-Aire fans, before "X" and "Y" classifications were established (http://qdg.sorbs.net/qdgnews.htm).
          Attached Files
          My first choice in quality Japanese electrolytics is Nippon Chemi-Con, which has been in business since 1931... the quality of electronics is dependent on the quality of the electrolytics.

          Comment

          Related Topics

          Collapse

          • edugimeno
            Vaillant 242 Gas Water heater. Shortcut in board anc compatibility with model 282
            by edugimeno
            Hi!!
            Yesterday I was installing a new Wifi thermostat for my domestic gas water heater model Vaillant 242/2-3, and accidentlly one wire from mains touched one wire from the thermostat output contacts. This shut off the heater so I finished installing the thermostat and then went out to check the heater

            I found one fuse blown (T2 250V). Replaced it with another equivalent fuse and it blew right away. I measured L-N in mains input and I sometimes got 4K but sometimes, not sure why, I got 100 Ohm...
            At a certain point, moving stuff around, I put all wires back in place and...
            03-24-2024, 02:31 PM
          • Dannyx
            Line filter question
            by Dannyx
            Good day folks. A while back, I started building a bench power supply (long story - see it here ). I noticed something about the pre-built line filter I wanted to use and it got me thinking whether it's a good idea to use it or not, at least in my particular case.

            If you zoom in and look at the schematic on the label, the potential problem I see is the earth terminal connected to L and N via the 2 Y caps. I've seen this setup in virtually all of these and even some SMPS board may have this arrangement (though I'm not sure about this), so it's probably safe overall and makes perfect...
            05-08-2022, 04:31 AM
          • madan1
            Diesel heater emergency power supply / poor man's UPS
            by madan1
            Hello everyone.

            Some background - I have one of those chinese diesel heaters, which I'm using to heat a garage. Probably most of you are familiar with that units, but here is some basic info - the main heater body is enclosed with the motherboard+sensors unit inside a plastic case. The heater has a glow plug, that works only when the unit is starting (start the fire in the burner) and stopping (make sure to completely burn the fuel inside the burner) and two fans on a single motor. One fan is used to push fresh air in the burner, the other is used to push cold air in the case and...
            12-18-2022, 08:05 PM
          • cubytus
            Samsung UN50TU8000FXZC shows thin horizontal green line when warm
            by cubytus
            Hi to all,

            I was given this TV, an entry-level 4K 50" set. Some have criticized its lack of contrast and relatively poor colour rendering, but for my needs, it's very decent.

            I reset everything to factory settings, but this line keeps on fading in and out when watching a streaming channel from the Tizen firmware. Interestingly, it only happens when TV is warm, after about 1h45 of it being turned on.

            Watching a movie from an external source doesn't trigger the line as easily (needs 2 hours), and from a normal viewing distance, is hardly noticeable. It...
            01-10-2024, 01:26 AM
          • sam_sam_sam
            Heater element wire type instead of a fuse when troubleshooting a short circuit DIY
            by sam_sam_sam
            I was Ollie today which is a close out / surplus outlet store I do not go in there to often because you find things that you should not be tempted by but that is a another story

            I saw a small space heater that used a wire type of heater element which I been looking for a while but not really hard mind you but when I saw this I grabbed it I going to go back tomorrow and buy the last one that is like the one I bought today because I need the heater element and the ceramic insulators and more of heat element wire because this one has two different wattage settings one 1300 watts ( tap...
            12-16-2023, 08:39 PM
          • Loading...
          • No more items.
          Working...