GSM-noise "buzz" issue

Torsten Sievers openmoko at
Thu Sep 11 13:35:28 CEST 2008

Hi Joerg,

good work so far. do you have any update on this?

On Tuesday 26 August 2008 14:22:54 Joerg Reisenweber wrote:
> We found it's pin4 of JK4401 and only this pin that causes GSM-EMI-noise
> issue.
> We placed a ferrite bead to this pin, and it stops noise. Alas this isn't a
> viable rework, as it is extremely fragile and doesn't fit into case.
> See
> <
> We tried to find another way to place a bead in this rail, first result
> (without bead yet), see
> <>
> This rework at least stops noise and should fit into case. It breaks
> function of headset mic and hold-button, but keeps function of headphones.
> We try to find a way to restore function of mic and button, based on this
> rework.
> I will keep you updated.
> Please note all this IS NO RECOMMENDATION FOR A REWORK, and we can't answer
> any questions yet beyond what I've reported above.
> cheers

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