SCREAMMMM

Discussion in 'Carphonics' started by CarpeDiem, May 10, 2019.

  1. 10 May 2019 at 3:59 PM #1
    CarpeDiem

    CarpeDiem

    Hi Gents

    Purchased an E46 M3 and have a very annoying issue with the sound system (it is OEM sat nav plus the HK subwoofer). Basically when I get into the car and turn the ignition (so all the electrics fire up), I get a LOUD SHRIEK or SCREAM strange noise for about 2-3 seconds coming out the speakers and then it goes away. Thereafter the sound system is perfect.

    I disconnected the Harmon Kardon sub woofer and no change.

    I then removed the BM54 unit and the noise was gone.

    I thought it might be the BM54 unit, so got a replacement and the issue is still there.


    Any ideas on where to look next???

    Cheers
     
    CarpeDiem, May 10, 2019
  2. 10 May 2019 at 4:43 PM #2
    Keith

    Keith Achieved official socks

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    I’m almost certain that is the BM54 unit. Very well known fault. Can you be certain your replacement is not also faulty?
     
  3. 10 May 2019 at 4:52 PM #3
    dino

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    Speak to Baris (xkalibar) at carphonics he is a sponsor on here
     
  4. 10 May 2019 at 5:54 PM #4
    CarpeDiem

    CarpeDiem

    Thanks gents - I’m quite sure the alternative BM54 is fine as it would be very coincidental to have the same ‘unique’ problem ?

    Does Baris still come onto cutters - if not will give him a call?

    Problem is I’m quite far from him, so might have to take it to a local audio specialist, but that would feel like I let the the problem beat me !!!
     
    CarpeDiem, May 10, 2019
  5. 10 May 2019 at 5:57 PM #5
    GolfDuck

    GolfDuck Staff Member Moderator

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    If you can try unplugging the H/K "sub". Has the screech gone?
     
  6. 10 May 2019 at 5:58 PM #6
    CarpeDiem

    CarpeDiem

    I’ve completely disassembled the HK sub in the boot and the screech is still there.
     
    CarpeDiem, May 10, 2019
  7. 10 May 2019 at 5:59 PM #7
    GolfDuck

    GolfDuck Staff Member Moderator

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    Quite puzzling but it's likely that Baris will know :)
     
  8. 10 May 2019 at 6:17 PM #8
    CarpeDiem

    CarpeDiem

    Here is a video - it doesn’t quite put across how loud it is, but suffice to say it’s embarrassing!!!

     
    CarpeDiem, May 10, 2019
  9. 10 May 2019 at 6:24 PM #9
    GolfDuck

    GolfDuck Staff Member Moderator

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    Oh, it's not a constant thing.
    Does it happen if you turn off the head unit then turn on the ignition and then turn on the head unit?
     
  10. 10 May 2019 at 6:32 PM #10
    CarpeDiem

    CarpeDiem

    Yes it will still happen :(
     
    CarpeDiem, May 10, 2019
  11. 10 May 2019 at 6:35 PM #11
    GolfDuck

    GolfDuck Staff Member Moderator

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    I see. I wonder if it's some sort of power spike. I hope you can get it sorted :)
     
  12. 10 May 2019 at 6:39 PM #12
    CarpeDiem

    CarpeDiem

    Thanks, that exactly what I think it is !
     
    CarpeDiem, May 10, 2019
  13. 10 May 2019 at 8:22 PM #13
    XKaLiBaR

    XKaLiBaR Sponsor

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    Hi, I’m so sorry, I do come on once in awhile, but completely missed this the other day. Thank you for the PM.

    Your fault is common.



    However, this fault is digital, so it’s either on or off, never goes off, unless an input like the volume or bass is adjusted.

    You say it goes away after awhile, are you changing modes or volume?

    When you have a chance, remove the Bm54 from your boot, and print and fill in the form

    http://www.carphonics.co.uk/forms/bm54&tv.pdf
     
  14. 10 May 2019 at 8:42 PM #14
    CarpeDiem

    CarpeDiem

    Thanks Baris - the only thing is I swapped the bm54 unit and still the same issue? The noise is at the point of turning the ignition and then stops?
     
    CarpeDiem, May 10, 2019
  15. 10 May 2019 at 8:51 PM #15
    XKaLiBaR

    XKaLiBaR Sponsor

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    Any chance you can record it and send it over to me. Email or text/WhatsApp me http://www.carphonics.co.uk/Contact.htm

    Was the other Bm54 100% working fine?

    Have you tried changing the hk amplifier?

    If you have an old speaker, house speaker or anything laying around, you can test the sound output directly from the back of the Bm54 connector, before it gets to the hk amp.

    Google Bm54 pin out and you can see which ones are the speaker ones. If the Bm54 is clear, then the fault is elsewhere.

    Does it happen on all modes ?
     
  16. 10 May 2019 at 9:24 PM #16
    CarpeDiem

    CarpeDiem

    Thanks Baris, I’ll ping you a WhatsApp:)
     
    CarpeDiem, May 10, 2019
  17. 17 May 2019 at 9:39 AM #17
    CarpeDiem

    CarpeDiem

    Firstly a big thanks to Baris for his patient help with this last weekend - just in case anybody else ever suffers with this issue it was indeed the HK amp (and not the one under the parcel shelf, but one that is next to the BM54 unit). With all the HK amp capacitors shot to pieces I replaced the whole unit with a new HK amp and all good :)

    Pictures as per post 110 on my thread here https://forums.m3cutters.co.uk/threads/number-7-black-e46m-coupé.199708/page-6

    Thanks for everyone’s help/input - really appreciated.
     
    CarpeDiem, May 17, 2019
  18. 17 May 2019 at 9:42 AM #18
    GolfDuck

    GolfDuck Staff Member Moderator

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    Glad to hear it's sorted :)
     
    CarpeDiem likes this.

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