Beovox S45-2 blown tweeter successful repair. What caused it?

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Home Forums Product Discussion & Questions Vintage Products Beovox S45-2 blown tweeter successful repair. What caused it?

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  • #37130
    louislemas
    BRONZE Member
      • Topics Started 1
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      Last year I saved a pair of Beovox S45-2s from going to the tip.

      I managed to successfully fix a woofer with a dislodged magnet – using tutorials from this site. I’ve enjoyed listening to them for a year, but thought I would give them an upgrade by replacing the (original) capacitors.

      I ordered this kit and successfully changed all of the capacitors in one speaker without hiccup. I left all of the old capacitors in the other speaker for a couple of weeks so I could compare the sound. Once I was satisfied that the speaker with new capacitors sounded better, I replaced the capacitors in the other speaker as well – again no hiccups as far as I could tell. I put it back together, plugged it into the amp (whilst switched off) – but then found there there was no sound coming from the tweeter. The woofer and filler worked fine.

      There was a discontinuity across the tweeter terminals. I thought I’d document how I was able to successfully repair the tweeter (PHILIPS AD-0163 T8), in case anyone else has the same issue…

      Upon closer inspection of the voice coil, I noticed there was a burn mark on the cardboard where the wire is soldered to the coil. Using tweezers and patience I was able to scrape and peel the glue back to reveal the wire leading to the coil. I then unravelled the coil slightly to allow enough length to solder. I was pleased that I was able to achieve all of this without losing any length in coil or wire. Once soldered I glued the coil and wire back into place.

      Now that the tweeter is showing continuity again, I don’t want to connect it back up to the crossover before I work out what caused it to blow. I would appreciate any ideas about what could have caused this and how I might be able to diagnose without blowing the tweeter again. If it is a faulty capacitor, which one is it likely to be and how can I diagnose this? (I just want to mention that I have no reason to believe that beoparts-shop.com supplied me with a faulty capacitor and have been happy with their service so far). Should I connect some fuse wire in series with the tweeter for testing purposes – if so, what rating? I am fairly confident that I soldered the new capacitors in the correct places, but have included pictures of the crossover for proof.

      PXL_20220820_193802796_2PXL_20220820_185613435_2PXL_20220820_192453155_2PXL_20220820_193645079_2PXL_20220820_194208683PXL_20220820_194227659PXL_20220820_194507465PXL_20220820_194446407

      S45-2sch.jpg-800x0

      (https://www.diyaudio.com/)

       

      #37131
      Mark-sf
      BRONZE Member
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        • Total Posts 297

        That type of damage is typically caused by overheating which can be the result of any of the following or in combination:

        1. clipping an amp into the speaker
        2. if the series capacitor, C2 was too large or shorted
        3. if the parallel resistor, R6 is open.
        #37132
        louislemas
        BRONZE Member
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          • Total Posts 2

          Thanks for getting back to me.

          It’s very helpful to know which components are most likely to be causing the issue, because I don’t want to desolder any that I don’t have to and risk applying excess heat to them.

          All of the capacitors are 15μF to match the originals. I just want to check – did you mean to say series capacitor C3? Because C2 appears to be in series with the filler rather than the tweeter.

          I will check R6 after the capacitor, because no heat was applied to it in the soldering process so I think it is less likely to be the issue.

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