buzz fix

Joerg Reisenweber joerg at
Tue Mar 31 23:11:47 CEST 2009

Am Di  31. März 2009 schrieb Peter Stumm:
> Hello, 
> 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?
> thanks 
> peter

Hi Peter,
I'm really sorry it didn't work for you on first shot.

The main problem with your fix seems to be the extremely long wires catching 
more RF which is creating noise directly in mic, than the whole rework is 
reducing noise introduced by MICBIAS ripple.
The recommendations to keep the wires *as short as possible* and run them 
*close to PCB (GND) surface* were chosen to avoid exactly this problem.
Probably you should replace the 0603 (0804?) big R4303 by a fitting 0402 and 
place this one on the pads directly so no wire is needed to contact it. You 
might keep the capacitor but you need to replace this wire with a short one 
as well.
If you got problems to find correct components don't hesitate to ask me to 
send some to you. Contact me either via private mail or on IRC freenode 
#openmoko DocScrutinizer

good luck

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