the soundgate saga, semi-over

Mike Arman armanmik at
Tue Feb 5 10:18:33 EST 2002

>To: 200q20v at
>From: Brett Dikeman <brett at>
>Subject: the soundgate saga, semi-over
>Cc: quattro at
>Adventures in I-Just-Want-To-Play-Some-#$@%!-CDs-Land, part IV: The Revenge.
>Turns out that the rear driver's side speaker is shot.  No prob, I
>think.  I'll just pop that bad boy open, replace the caps, and I'll
>be set!
>I pull the potting compound off the board(there's a ton of it on this
>particular board), replace all the capacitors, and put everything
>back together and in the car.
>Turn on the radio, listen for about 10 minutes...problem starts happening.
>So this time, I turn the volume almost all the way down and endure
>the various odd noises, which curiously quiet down after a few
>seconds.  Hmm.  I then go around to each speaker and listen carefully
>to what it is doing.
>The driver's side rear unit is cutting in and out and then starts
>making bop! bop! bop! bop! noises.  Shoot.

This is called "motorboating" and indicates a power supply problem, usually
an open filter capacitor.

Go back and check your work, make sure all the grounds are connected, and
nothing else has come off the PC board.

Best Regards,

Mike Arman

>So, at this point, I'm stuck; I have no idea what's wrong with the
>rear unit, since I replaced all the electrolytic capacitors, just
>like I did on the front units, and they seem to be just fine.

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