[Shr-User] uSD hosed, on every unstable.

[Al Johnson]

On Wednesday 13 October 2010, jeremy jozwik wrote:
> On Wed, Oct 13, 2010 at 6:22 AM, Al Johnson
> 
> <openmoko at mazikeen.demon.co.uk> wrote:
> > Judging by your photo and the component placement doc that would be R7507
> > which according to the schematic is 75R, and connects the SD_DATA0 pin on
> > the connector to the chip. That certainly explains why your SD won't
> > work!
> > 
> > No - the 4 components are resistors not capacitors. The capacitor fix
> > hasn't been needed since the full kernel fix that correctly implemented
> > the Glamo's SD drive strength adjustment.
> > 
> >> i have taken images and will upload them. but i wanted to put this out
> >> first.
> 
> R75707, well this is good and bad news. the good news, our developers
> do indeed know what they are doing!
> 
> the bad news, i need to try to solder something back on there. ok, so
> its a resistor, any more information?
> 
> make model micro soldering tutorials? i would really really like to
> fix this if i can.

You can find the schematic and layout documents here:
	http://downloads.openmoko.org/developer/schematics/GTA02/

75 Ohm and the correct size are the critical bits. Resistor tolerance 
shouldn't be an issue. I think the size is 0402 but you can check this by 
measuring (ruler, magnifying glass) before you buy, or hope someone who 
actually knows replies ;-)

Here's one of many smt tutorials on the net. These won't be the easiest bits 
to start with though! If you've got a broken old motherboard or HDD to 
practice on it would be well worth doing.
http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=36&page=1