[Arm-netbook] SHIPPING!: EOMA-68 Micro Engineering Boards

joem joem at martindale-electric.co.uk
Wed Aug 14 17:00:09 BST 2013


On Sun, 2013-08-11 at 23:53 +0100, luke.leighton wrote:
> On Sun, Aug 11, 2013 at 8:17 PM, Christopher
> <christopher at firemothindustries.com> wrote:
> > Given the issue with the uarts, Is it too far fetched to consider the differential pairs got swapped? (I.e. pin 68 isn't actually going to SATA B- and so on...) I know all the pins on the MEB match the PCMCIA connector. But perhaps the 68pin on the cardedge is misrouted on the a20 card. (Which would require soldering as you mentioned. )
> >
> > Also, everyone might want to look at their card edge connectors on the a20 PCB. Tried booting up one of mine and it worked and then halted. Looked at the connector and saw pin 66 and pin 33 were slightly bridged (tiny tiny blob of solder was in a peak pointed at the connector )
> 
>  ok i think i got it.
> 
>  http://www.elecraft.com/Apps/caps.htm
>  http://hands.com/~lkcl/eoma/a20_sata/cb_sata.png
>  http://hands.com/~lkcl/eoma/a20_sata/sata_conn_sch.png
> 
> according to that elecraft link, "103" is 10nF (0.1uF).  someone's
> changed that to "103pF", without authorisation... and without telling
> us it had been done.  again.  the number of unauthorised modifications
> to the schematics by the design house... i'm just... blown away.
> 
>  *sigh*.
> 
>  ok.
> 
>  luckily this means that no PCB mods are required: just a trip to a
> SMT house that can do 0402 components (by hand).
> 
>  can i ask people to check something: could someone please take a
> close-up hi-res photo of the 68-pin connector, TOP side, near pin 56?
>  http://elinux.org/Embedded_Open_Modular_Architecture/EOMA-68#Table_of_EOMA-68_pinouts

Lot of internal bridging

http://www.gplsquared.com/eoma_boot/bridge1.jpg
http://www.gplsquared.com/eoma_boot/bridge2.jpg

Checked with multimeter.
A Bernstein 5-054 tweezer should be able to clean it out without
having to use a soldering iron (iron can only make it worse in the hands
of anything less than an expert).



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