GTA02 Power Glitch Reason Found
andy at openmoko.com
Tue Feb 5 11:39:27 CET 2008
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Somebody in the thread at some point said:
> Andy Green wrote:
>> Well soon there will be plenty of A5s so the old GTA02 will be
> Hmm, they might be handy to have around in case an A5 blows up, and
> mail is slow.
Well if you are brave and have some solder braid around, there are a few
places around the PMU package where two pins together have that net.
This is always a nice advantage since you can deliberately blob solder
between the two pins that are already shorted together and place the leg
of the component between them too.
>> But it is a whole new ballgame
> BallGAme ? ;-) Luckily the PMU isn't one of them ...
Right, I was able to get a probe in there.
>> It was a problem since GTA02 A1 where we changed to the PCF50633... it
>> can explain a long list of unstable PMU behaviour
> Oh yes. We also have "high speaker volume freezes the phone".
LOL... hopefully not any more.
>> The rework is probably going to make a headache
> If there's a little bit of space, it may be pretty easy to do this in
> the SMT process, by shifting components a little so that they can
> share pads. Surprisingly, this sort of hack is actually supposed to
> yield perfectly good connections.
Sure -- but care is needed below (for other components) and above (for
the can), some insulating tape will probably do it.
> By the way, do you have a picture of your rework ? My GTA02v5 might
> arrive today, and a bit of soldering may be the perfect welcome :-)
Here we go. The right-hand (+ -- don't be confused by the big black
line!) pin of the cap is going to the left-hand pad of the first
resistor in the column there. The big ugly solder blob on the left is
0V from that other cap. I think this guy is 10uF, I noticed one of the
later datasheets for the PMU proposes 22uF FWIW.
With this -- random standby problems plaguing me for days are all gone.
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