[Arm-netbook] Fwd: [eoma68 update] report back from factory on HDMI

[David Niklas]

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On Wed, 3 Jul 2019 09:03:44 +0100
Luke Kenneth Casson Leighton <lkcl at lkcl.net> wrote:
> ---------- Forwarded message ---------
> From: Luke Kenneth Casson Leighton <lkcl at lkcl.net>
> Date: Wed, Jul 3, 2019 at 8:16 AM
> Subject: [eoma68 update] report back from factory on HDMI
> 
> Mike's staff began the PCB assembly of the run of 100, and had to stop
> at 36.  20 were ok: 16 of them, the HDMI connector refused to fit.
> The reason: the CNC machining on the edge of the PCB has not been done
> accurately enough: it's simply too ragged.  The staff did some
> experimentation, cleaning up some of the edges in the cut-out with an
> xacto-knife: this did the trick, even though it is shaving something
> like 0.01mm off the ragged edge of the PCB.
> 
> The left and right edges do not matter too much, however where the
> HDMI connector comes in close, it definitely does.  Mike is going to
> talk to the PCB factory to see if there is anything that they can do
> in future, however with 1,000 PCBs already manufactured, the safest
> thing to do is probably to *hand-trim* that PCB edge, removing the
> burrs, on all 1,000 PCBs.
> 
> Again, to reiterate, because I am still seeing evidence of
> "complaints" out there, from people who believe this should be easy:
> these are absolutely ridiculously tiny components and tolerances, and
> the budget on which it's being done is equally as frugal.  0.05mm on
> the edge of a PCB.  0.2 mm wide pins, with 0.2mm clearance between
> them.  A "normal" Single-Board Computer product from any other
> well-funded Corporation would use large (Type A) HDMI, top-mounted,
> with plenty of tolerances and no need for the PCB edge to be
> accurately milled.
> 
> Again, to reiterate: we do not know what will need to be solved next.
> Therefore, a production date simply cannot be provided, and that
> really is the end of the matter.  Or, the answer is: the production
> date is "the production time plus the unknown time to solve unknown
> and unknowable future issues".
> 
> Mike is sending me the 20 "good" PCBs so that I can test them here, to
> see if they are okay.  The staff will continue with the rest by
> shaving the burrs on the PCB on every single one of the remaining 80
> with an xacto-knife, before putting them through the production line.
>  It is looking like I will need to do the testing of all 100 of this
> preliminary production run, here, at my home, in Taiwan.

Maybe you should be focusing on FLOSS PCB tooling instead of Laptops. (-;
More seriously, from my experience it seems as though a lot of the
"professional" tools have major design problems. As though the engineers
gave up halfway through at the "test it in the real world" phase.

Sincerely,
David
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