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Wireless Headphones - Filter Missing/Unknown

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    #1

    Wireless Headphones - Filter Missing/Unknown

    These are the stock headphones for the VES entertainment system from a 2009 Chrysler Town and Country. My son managed to break both before I could attempt to use the good one to fix the bad one. Both exact same - L4 broken.

    How do I find a replacement part ?
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    #2
    Re: Wireless Headphones - Filter Missing/Unknown

    Need some help with this.

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      #3
      Re: Wireless Headphones - Filter Missing/Unknown

      Did they just suddenly stop working? What do you mean by "son managed to break both", that something he did wrong caused the 2nd to fail, or only that the 2nd one failed before you could examine and compare to the first failed one?

      L4 seems to be a chip inductor, and while the pictures are not great it almost looks like there is now a jumper wire soldered in its place, is that something you've added and it didn't help, the same problem persists?

      Are we looking at the entirety of the circuit, is there anything else on the rear of the pictured PCB? I presume the battery pack (and speaker of course) is the only thing in the other earpiece?

      Can you identify the IC, it looks like it is labled "Un Wire" but I can't make out the rest, and tracing that inductor back to the IC, what pin # does it connect to? It could be harder for us to trace the circuit without a clearer image, with lower compression, and a same-size, same orientation bottom up image to align with the top down pic.

      Personally I would opt to pull the PCB out and scrub all that flux residue crud off with alcohol and a stiff toothbrush. It looks like a pine resin type hygroscopic formulation that really should have been cleaned off the board at the factory since it is potentially exposed to humid environments in automotive applications.

      I can't tell for certain but the damaged L4 may be the same value, 2nd channel equivalent the subcircuit L3 is in, so if you find a fault you could try pulling L3 off one pair and putting it where L4 was on the other pair. However I don't think this component is the primary fault, that some other fault caused it to fail and the other fault needs fixed first, AND I wonder if it is even worth your time since it would appear this is a poor design prone to fail again with the 2nd pair of cans failing already.

      Nevertheless I'd clean up that flux residue and examine the board for shorts, touch up any questionable solder joints, then see if there is any transistor output buffer stage that might have blown, although if the red and white wires are the speaker lead then it looks like that IC directly drives without transistor buffer assistance.
      Last edited by 999999999; 02-24-2014, 10:47 PM.

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        #4
        Re: Wireless Headphones - Filter Missing/Unknown

        Yes sorry the van came with two pairs of these and they both now have the inductor crushed after being stepped on exiting the vehicle.

        Yes I put a jumper over it trying to complete the circuit. This was a long while ago but as I have a road trip scheduled in the near future I am revisiting this repair with an eye to do it right The jumper didn't work. The headphones turn on but no sound is heard - my assumption was that the inductor was part of the frequency tuning circuit and so couldn't lock the signal. But I think these are IR not RF don't know if tuning is necessary ??

        I looked at L3 and it appeared to be a different size. I will look again and harvest it from one pair if it looks same.

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          #5
          Re: Wireless Headphones - Filter Missing/Unknown

          Well, if they were being stepped on then any random solder joint or component might also be damaged. If you have access to one, after cleaning all the old flux off I'd put flux on the entire board and reflow the whole thing with a hot air gun.

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            #6
            Re: Wireless Headphones - Filter Missing/Unknown

            This may be true however the inductors were the only visible damage presumably because they sit higher than the other smt devices.

            Even a reflow won't help with the inductor broken so tomorrow (I'm at work) I will remove L3 from one set and place into L4 in the second set and see where I'm at.

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              #7
              Re: Wireless Headphones - Filter Missing/Unknown

              Swapped out L3 from set 1 into L4 of set 2 and it's working. Seems to be in mono but can't be sure just yet.

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