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 _______________________________________________ hardware mailing list [email protected] http://lists.openmoko.org/mailman/listinfo/hardware
