[Elecraft] [K3] K3 Rev C DSP with Low Freq Enhancement ship date info; New swap out option on parts order page. CORRECTION

[Brett Howard]

I have a lot of confidence in SMT rework and I've done the C9 and C13
mod with exact replacement caps.  I was told that changing those to
100uF was an official Elecraft mod so I went out and found the exact
size replacement SMT caps and got them on there.  They look like they
were installed from the factory.  I've got all the equipment to do SMT
rework right down to removal and replacement of BGA components.  If I
just had an official list of modifications I'd just do it.

Wonder if the replacement DSP board requires the return of our current
one.  My current one has traces cut for the low pass audio filter and
what not...

~Brett 

On Sat, 2009-10-10 at 07:37 -0400, Paul Christensen wrote:
> > This should be close but Elecraft has not updated their schematics since
> > October 2008, so there could be differences:
> >
> > http://n1eu.com/K3/k3audiomod.htm
> 
> Lyle and I exchanged notes on this a while back as he and I were 
> experimenting with DSP Board component changes above and beyond the 
> much-discussed headphone cap change.  My guess is that the Rev. C board 
> changes take the notes in the link into account.  However, he was re-scaling 
> R values.  I had re-scaled C values since fewer components were involved in 
> solder re-work.  The net result is essentially the same but changing R 
> values likely makes more sense in production where the cost of SMT resistors 
> is essentially the same irrespective of component value versus the increased 
> cost of higher-valued capacitors.  And as Bill points out, there may be 
> other subtle differences.
> 
> Given the number of changes to the DSP Board, I recommend taking advantage 
> of Elecraft's swap-out program unless there's a lot of comfort in SMT/SMD 
> re-work.
> 
> Paul, W9AC 
> 
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