[QtMoko] handset is (almost) unusable for voice calls with background noise

Joerg Reisenweber joerg at openmoko.org
Tue Jun 15 17:11:43 CEST 2010

[Peter Nijs Di  15. Juni 2010]:
> On Tuesday 15 June 2010 10:58:41 Joerg Reisenweber wrote:
> > Some FR have a problem of 2 capacitors in path to earpiece reducing max 
> > possible earpiece level, while others have a correct 2 pcs 0R "wire"
> >  instead.  Actually for those I heard several complaints earpiece is too
> >  loud :-)
> I also have the problem the earpiece is too quiet. I set "bypass" and 
> volume" to maximum in SHR-testing. Especially in China (china mobile) I 
> couldn't use my FR because the operator seems to lower the volume 
> Can I expect the cap problem in the A5?

IIRC it was completely impossible to find out about the exact builds that had 
the useless capacitors, as I couldn't find decent BOM which mentioned for 
which SER# it applies

> And can I exchange these caps with 
> 'wire' (or a drop of tin myself?

Yes, it's "easy" - you probably even can use silver varnish to short the 
capacitors. Just check the schematics and component placement, there are only 
2 (symmetrical) 0R mentioned in earpiece patch, in series from amp to the 
transducer. You have to open a can to reach them IIRC. This also should be 
mentioned on hardware ML, and probably as well in wiki.

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