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Help identifying blown component

Discussion in 'Troubleshooting and Repair' started by Ross161, Oct 3, 2014.

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  1. Ross161

    Ross161

    3
    1
    Oct 3, 2014
    Hello electronics brains!

    My freezer is broken, tracked fault down to the fan which is not spinning. A replacement fan and motor assembly is going to cost me £95, and it looks like its just a 50p component that has blown on the control board.

    My electronics knowledge is pretty basic, but it looks like a fat resistor, or possibly a capacitor. It looks to be coated in resin, and contains layers, but there are no markings, and the casing has cracked open. It has blown, and also damaged the tracks on the board. You can see the offending item sticking out on the photos I have included.

    The component was connected to one of the terminals on the 230V AC input to the board, as the tracks have gone I cannot tell if it was sitting in series with the input, or across it.

    In testing, I have connected it back up, (in line with the 230v in), and the motor runs for a few minutes before the component gets hot and my soldering falls apart. This makes me think it's totally ruined, or assuming its a cap, maybe should be wired in parallel to the incoming 230v.

    Can anyone identify this? I am assuming is must be a fairly standard / common component.

    If it's a capacitor, am I right in thinking this should be wired in parallel, ie both sides of the capacitor connected to the same incoming 230v live?

    Or is it a resistor, to be wired in line with the input?

    In my pics you can see the tracks which have lifted. The black circle on the 3rd pic is where the other side of the component used to be seated.

    If anyone can point me in the right direction I would be most grateful. Would rather spend a few quid on a new one of these things that a whole new motor!!.

    Thanks again
    Ross



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  2. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,271
    Nov 28, 2011
    Hi Ross and welcome to Electronics Point :)

    It's a coated wirewound resistor, probably rated around 5 watts. You may be able to measure it wih a multimeter on resistance range if the wire hasn't actually gone open circuit or been damaged.

    It would not have been connected across the AC input. It could have been connected in series.

    The large grey capacitor, marked with R.46 etc, looks to have been damaged as well, and may have been the cause of the resistor overheating. Suitable replacements are here; http://www.digikey.com/product-search/en?pv5=10136&pv5=10137&pv5=10139&FV=fff40002,fff80010,3400fd,1140050,1430001b,1430001e,1430001f,14300021,14300023,14300024,14300028,14300029,1430002c,1430002d,1430002e,14300030,14300031,14300032,14300034,14300035,14300038,1430003b,1430003c,1430003e,14300040,14300041,14300045,14300054&stock=1&quantity=1&pageSize=250. Check the dimensions against the original, especially the lead pitch, for a match.

    The board has been pretty badly damaged by excess heat. Scrape off any black or brown material with a scalpel, give it a clean with a solvent (isopropyl alcohol aka tape head cleaner is best if you can get it) and take some new photos.

    If you replace the resistor and the large capacitor and the resistor still overheats after a few minutes, the problem could be in the other components on the circuit board - there is obviously some more circuitry on there - but could also be due to friction in the motor itself. See whether the motor turns freely or not, and whether the wide cylinder on the shaft is touching the surrounding laminations when it's fully assembled. You may be able to tap things with a hammer to change the exact positioning of the shaft to stop it from touching the sides.

    Edit: check the motor before you replace the capacitor. But you will want to replace the resistor before you refit the motor assembly into the freezer.
     
  3. Ross161

    Ross161

    3
    1
    Oct 3, 2014
    Thankyou Kris - that is awesome. I will try and source replacement bits and see how I get on. Will report back with some good news hopefully.

    Again many thanks for your insight it is appreciated.
     
    KrisBlueNZ likes this.
  4. Bluejets

    Bluejets

    4,618
    977
    Oct 5, 2014
    Difficult to say what all the electronics do in there as the motor is just a standard synchronous motor as used in most frig/freezers.
    A bit hard to see as some of the board is not in the photo.
    Normally the coil on the motor connects directly to supply.
     
  5. Ross161

    Ross161

    3
    1
    Oct 3, 2014
    Hi Kris - was a 50 Ohm resistor, found one in 5W flavour online, I also bought a 3W one but it looked skimpy compared to the old one so I played it safe. I also replaced the capacitor as you recommended. Cost me about £2 plus £12 shipping! A lot cheaper than a new motor. I haven't tested it yet but will know later if it's worked.

    Again thanks for your advice. I work in software development and IT support, if there is every anything I can help you with please let me know as I would be happy to return the favour.

    Cheers
    Ross



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