Did you measure the capacitor on other "normal" phones?<br>If on the phones without the problem capacitor measures around 10uF as supposed than we have our solution :)<br><br>Leonti<br><br><br><div class="gmail_quote">
On Wed, May 6, 2009 at 5:48 PM, Dieter Spaar <span dir="ltr"><<a href="mailto:spaar@openmoko.org">spaar@openmoko.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Hello,<br>
<br>
I spent quite a lot of time to modify and patch<br>
various settings in the GSM firmware trying to change<br>
the behavior of the two phones which show the extreme<br>
"Deep Sleep" problems (immediate PCH reception error<br>
if the phone enters "Deep Sleep").<br>
<br>
Those modifications did not remove the problems and<br>
also did not cause any problems for the working<br>
phones I have. So till now it seems that there is<br>
no software workaround which can solve this problem.<br>
<br>
However on one phone I was able to solve the problem<br>
by replacing a capacitor which buffers one of the<br>
power supply lines of the Calypso chip (the power<br>
comes from an LDO in one of the other GSM chips).<br>
This capacitor is supposed to be 10uF, however<br>
I measured 7.6uF. I don't have SMD parts here so<br>
I replaced it with a standard 10uF electrolytic<br>
capacitor (I measured 10uF). After this<br>
modification the "Deep Sleep" problems are gone<br>
and the phone works as good as the other good ones.<br>
<div class="im"><br>
Its still too early to conclude anything from<br>
</div>the above. I have ordered a few SMD capacitors<br>
and will try the same with the other problematic<br>
phone. Additionally its necessary to test if this<br>
modification just moves the problem to lower<br>
temperatures (remember, the problems also go<br>
away if I warm up the phones by a few degree).<br>
<div><div></div><div class="h5"><br>
Best regards,<br>
Dieter<br>
<br>
<br>
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</div></div></blockquote></div><br>