GTA02 C4110/1 replacement?

Joerg Reisenweber joerg at openmoko.org
Sat Sep 13 03:57:17 CEST 2008


Am Di  9. September 2008 schrieb Al Johnson:
> On Monday 08 September 2008, you wrote:
> > On Mon, 8 Sep 2008, Al Johnson wrote:
> > > Some time ago Joerg (IIRC) suggested it might be possible for the
> > > brave/foolhardy to replace the undersized caps in the headset output 
with
> > > something more suitable, or even with audiophile esoterica like Black
> > > Gates. Looking at the schematics I see these are C4110 and C4111 which
> > > appear to be located under the can that has the bluetooth module stuck 
to
> > > the top of it. So how easy is it to open and close this can without
> > > breaking anything?
> >
> > Hi,
> >
> > I tried, just to see if I could do it, to add a capacitor in parallel to
> > the VB_SYS one: this is the solution the OpenMoko-people were researching
> > to get rid of the
> > gta02-won't-boot-on-an-empty-battery-even-with-usb-connected-thing. My
> > experience: Don't do it unless you have experience with soldering tiny
> > SMD-stuff, and the tools to do it. It's almost trivial to destroy stuff if
> > you don't have the experience.
> >
> > (btw, I made pics of my endeavour; if anyone wants to see them, just raise
> > your hand and I'll upload them.)
> >
> > Jeroen
> 
> I've done the odd bit of rework on tiny SMD stuff before, so that's not so 
> much of a worry. I'm more worried about breaking something while lifting the 
> lid, especially with the bluetooth module where it is.

I lifted quite some can lids, by using a small knife or screwdriver (knife 
works better).
There's no issue with BT on lifting the lid, you just need 10 minutes of calm 
repeating same effort until you finally succeed.

Capacitors are the right ones (IIRC), you cam simply solder some wires to 
them, and route those to any place where you are able to position decent 
ones. You even might cut a small hole to the can for this purpose.

Or you just short them, and place the real good ones inside your headset jack 
outside of GTA02 ;-)


Please come up with a photo footage on your rework, as I fear I don't find the 
time soon to do that myself. :-)
You got schem and component placement. It should be easy ;-)

cheers
jOERG

ps: you also might want to short the 33R, they're useless as soon as you got 
decent C (needed for GSM-DL firmware flashing via hs-connector, if at all)
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