strange crashes in current main branch

Christophe Devine devinechristophe at gmail.com
Wed Apr 23 17:48:00 UTC 2014


Tim,

Following your advice, I disassembled a battery, and directly connected the
output of a 3.6v motorola charger to gnd and positive side of the charging
pcb (of course the lithium cell is completely disconnected). See pictures
below, gnd is the middle pad whereas the positive pad is on the left. When
doing so be careful not to heat or pierce the lithium battery, and
afterwards put some tape to ensure electrical isolation:

https://drive.google.com/file/d/0ByHQWL5Q6bSwOHVPNlV5T2ZyZndLZmwtMF9JQ2V0eHhSNFhn/edit?usp=sharing
https://drive.google.com/file/d/0ByHQWL5Q6bSwTGNfeUFOVFM5cldPNFZ3djMyMmlSNVZ5dlNZ/edit?usp=sharing
https://drive.google.com/file/d/0ByHQWL5Q6bSwUm9XUnBOcU5SRFg4T3VpNEFZOUFHaUFSUEk0/edit?usp=sharing

The result appears to work although strangely sometimes after unplugging
the charger for some time and replugging it the microcontroller on the pcb
will not wake up. However it does immediately wake up if I measure the
current between the + and - output with a basic multimeter, but with the
black probe on the + and the red probe on the - (other way does not work).
There's probably something I'm missing here, but it's not that big a deal.

Maybe this is caused by a quirk in the microcontroller, as I've tried the
same procedure on a new compatible battery (branded "OTB", see
http://pmcdn.priceminister.com/photo/926610349.jpg) and it doesn't have
this problem, the microcontroller wakes up immediately and powers the
phone. The voltage might be a bit too high, but the phone seems to work
fine (firmware reports a full battery - also it gets slightly hotter).


On Wed, Apr 23, 2014 at 3:05 PM, Christophe Devine <
devinechristophe at gmail.com> wrote:

> Tim,
>
> Following your advice, I disassembled a battery, and directly connected
> the output of a 3.6v motorola charger to gnd and positive side of the
> charging pcb (of course the lithium cell is completely disconnected). See
> pictures below, gnd is the middle pad whereas the positive pad is on the
> left. When doing so be careful not to heat or pierce the lithium battery,
> and afterwards put some tape to ensure electrical isolation.
>
> The result appears to work although strangely sometimes after unplugging
> the charger for some time and replugging it the microcontroller on the pcb
> will not wake up. However it does immediately wake up if I measure the
> current between the + and - output with a basic multimeter, but with the
> black probe on the + and the red probe on the - (other way does not work).
> There's probably something I'm missing here, but it's not that big a deal.
>
> Maybe this is caused by a quirk in the microcontroller, as I've tried the
> same procedure on a new compatible battery (branded "OTB", see
> http://pmcdn.priceminister.com/photo/926610349.jpg) and it doesn't have
> this problem, the microcontroller wakes up immediately and powers the
> phone. The voltage might be a bit too high, but the phone seems to work
> fine (firmware reports a full battery).
>
> Christophe
>
>
> On Thu, Apr 10, 2014 at 8:44 PM, Tim Ehlers <osmocom at ehlers.info> wrote:
>
>> On Thu, 10 Apr 2014, Max.Suraev at fairwaves.co wrote:
>>
>>  I modified the mobile battery, removing the battery itself, and
>>>> replacing it with a
>>>> 3.7V AC-Adapter, so that I don't need the charging.
>>>>
>>>
>>> Interesting - can you describe those modifications in more details?
>>> Which adapter have you used? How did you connect it exactly? Some pics?
>>>
>>
>> ohh, this is no "advanced" modification. I just read on the battery, that
>> it outputs 3.7V, then I found for an ACDC-adapter, outputing 3.3V DC (this
>> is enough, but the phone tells you that the battery is nearly empty if you
>> boot the original firmware; but we use osmocom :).
>>
>> I openened the white plastic cover (or more correct, opened the sticker
>> around the battery), removed the Li-ION battery from the little electronic
>> parts and soldered the DC-adapter there instead.
>>
>> Cheers
>>
>> Tim
>>
>>
>
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