GSM-noise "buzz" issue

[Angus Ainslie]

On Fri, Sep 12, 2008 at 7:20 PM, Joerg Reisenweber <joerg at openmoko.org>wrote:

> Am Fr  12. September 2008 schrieb Andy Green:
> > Somebody in the thread at some point said:
> >
> > | Even thought this is not not a recommended rework I started on it. I
> > | (wrongly) assumed by just removing the connector that it would fix the
> > | noise issue. It doesn't.
> >
> > Wow, interesting.
> >
> > Can you describe what you did to make the "noise" come?  Is this the GSM
> > "buzz" type noise or something else?
>
> Yes Angus, please be more verbose on your findings!
> Until now all our results mean we don't see any noise at all, as soon as
> there's not even 2mm of wire on pin4 of JK4401. :-/ (leave allone beads
> etc)
>
> So if you removed headset-receptacle JK4401 from PCB, didn't add any
> other "antenna" on pin 4, and still hear GSM-buzz-noise on far end(!), I'd
> really like to see/understand this setup!
>
>
The sound I had  after completely removing JK4401 was the identical GSM buzz
that I had before removing the connector. I would say that it was possibly
even worse than with the connector attached.

I didn't have the connector with me so to try and rectify my partial rework
I added a short between 3 and 5 to match the closed connection in the
headset plug. That fixed it. There is a very minor hiss that remains but the
phone is usable for talking now.

I probed the connector a bit and the strip of metal up the side above pin 4
is connected to pin 4. Couldn't pin 4 be filed off. Then lean ( and solder )
the bead from the pad for pin 4 against the metal strip up the side of the
connector ?

Angus
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