buzz fix

Peter Stumm peterstumm at
Tue Mar 31 21:25:20 CEST 2009

a good friend does the buzz fix for me, but after doing that there is
still a buzz, think it's a little bit quiter.
here are a few pictures after the buzz

can you say me whats wrong?


Am Mittwoch, den 04.03.2009, 09:09 +0100 schrieb Joerg Reisenweber:
> Am Di  27. Januar 2009 schrieb Paul Fertser:
> > 
> > Al Johnson <openmoko at> writes:
> > > On Monday 26 January 2009, Christoph Siegenthaler wrote:
> > >> are there any updates from resellers, FIC or any half-official
> > >> DIY-tutorials on the hardware problems, i.e. the buzzing?
> > >
> > > This appears to have benefited from feedback regarding capacitor types 
> from 
> > > the few people so far to have attempted the mod, 
> > 
> > The feedback is that: you can use any cap, including tantalum. :)
> > 
> > > but more feedback is requested. The lack of feedback from people
> > > trying it may be why it hasn't yet made it past release candidate
> > > stage.
> > 
> > No more feedback is really needed. Everyone who performed the rework
> > confirmed that it eliminates the buzz. No single negative report. And
> > i guess at least 10-20 people have already tried the rework. So, the
> > reason that no reseller is doing it yet is probably due to
> > communication/business issues rather than technical.
> Exactly.
> I'm not in charge any more to push this fix, but to me it seems we really 
> don't need to quantify "how much it improves" buzz-issue.
> The cause and ways to creep in of buzz are well understood by now by some guys 
> at least (and NO it's NOT the mic catching RF near antenna, it's pin4 of 
> hs-jack), the bigC-rework is evidently (based on empiric and EE basics) 
> eliminating the ripple we see on MICBIAS, and a gsmhandset.state file 
> correctly using differential input mode (control.63 value "Mic 2") won't 
> break audio function from unfixed to buzzfixed FR.
> Also we don't need any sophisticated test procedure, as
> * all devices are prone to buzz issue, so we don't need to prove there is buzz 
> before fix
> * the big-C rework will either kill the buzz or you find you did sth wrong and 
> mic stops to work. So any engineer doing the actual fix doesn't need any 
> sophisticated "fix succeeded" test more complicated than that involved in 
> replacing a lightbulb. Test call -> works -> fine.
> cheers
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