Bug #1024 (oscillating re-camping), the latest news.

[Leonti Bielski]

Did you measure the capacitor on other "normal" phones?
If on the phones without the problem capacitor measures around 10uF as
supposed than we have our solution :)

Leonti


On Wed, May 6, 2009 at 5:48 PM, Dieter Spaar <spaar at openmoko.org> wrote:

> Hello,
>
> I spent quite a lot of time to modify and patch
> various settings in the GSM firmware trying to change
> the behavior of the two phones which show the extreme
> "Deep Sleep" problems (immediate PCH reception error
> if the phone enters "Deep Sleep").
>
> Those modifications did not remove the problems and
> also did not cause any problems for the working
> phones I have. So till now it seems that there is
> no software workaround which can solve this problem.
>
> However on one phone I was able to solve the problem
> by replacing a capacitor which buffers one of the
> power supply lines of the Calypso chip (the power
> comes from an LDO in one of the other GSM chips).
> This capacitor is supposed to be 10uF, however
> I measured 7.6uF. I don't have SMD parts here so
> I replaced it with a standard 10uF electrolytic
> capacitor (I measured 10uF). After this
> modification the "Deep Sleep" problems are gone
> and the phone works as good as the other good ones.
>
> Its still too early to conclude anything from
> the above. I have ordered a few SMD capacitors
> and will try the same with the other problematic
> phone. Additionally its necessary to test if this
> modification just moves the problem to lower
> temperatures (remember, the problems also go
> away if I warm up the phones by a few degree).
>
> Best regards,
>  Dieter
>
>
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