Re: gEDA-user: sparkfun 4 layer boards

["Mark Rages" <markrages@xxxxxxxxx>]

On Sat, Aug 23, 2008 at 12:52 AM, Dave N6NZ <n6nz@xxxxxxxx> wrote:
> Eric Brombaugh wrote:
>>
>> What sort of shorts are you seeing? I'm assuming that on a 2-layer
>> board they would ordinarily be pretty easy to correct by appropriate
>> use of an knife. Or are they internal/inaccessible? Is that even
>> possible on a 2-layers?
>
> You'd think they'd be easy to find.  On the board I blindly assembled,
> there was a short to the ground plane somewhere.  I spent more time than
> it was worth looking for it, and scraped away at a couple of suspicious
> spots with an X-acto knife.  Never did isolate it.  On the second
> shorted board, it was another short to the power plane somewhere.  After
> I confirmed it, I just marked the board and threw it in the NFG pile.
>

I've had moderate success clearing blind shorts with the 5V bus of a
high-power computer power supply.  (This can be hazardous to other
parts on an assembled board)  Otherwise, use a current-limited power
supply to put a few amps into the stuck node.  Use a millivolt meter
to measure different places on it.  Lower voltage means closer to the
short.

Regards,
Mark
markrages@gmail
-- 
Mark Rages, Engineer
Midwest Telecine LLC
markrages@xxxxxxxxxxxxxxxxxxx


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