Re: K2 - KDSP2 Circuit Diagrams

[KBG Luxford]

Hello to the List,

I realised that I had not finished the story about the problems I had
with my KDSP2.  My ineptitude may serve as a cautionary tale for others
- who knows?

Anyway to recap:
I purchased the KDSP2 option, assembled it, found it a bit stiff to plug
the DSP processor board into the KDSP board.  However, DSP worked just fine.

Later I wanted to get at the control board, but found that I could not
pull the DSP processor board out so that I could get at one of the
screws holding the control board to the display board.  There was,
however, a workaround, but it was awkward.

I decided to replace the DIP and SIP plugs.  I carefully (so I thought)
removed the plastic parts with sidecutters, removed as much solder as
possible with solder wick, then with pliers and soldering iron, pulled
the pins out one at a time.  The holes were cleaned out with a short
length of tinned bus wire held with pliers and heated with the soldering
iron.  New plugs were soldered in place, the KDSP2 re-assembled and
re-installed, K2 buttoned up and switched on.

DISASTER - KDSP2 would not work.

I traced the connections from the plugs to components on the board.  I
found that at least one circuit board trace had been damaged.  Repairing
this did not solve the problem.  Found another probable fault between
another pin and the board components to which it was supposed to be
connected, but by this time had just about decided that with my limited
skill in boards with modern, surface mounted components, that it might
be better to just try a replacement.

Firstly, I replaced the microcontroller, but this did not solve the
problem.  Then Scott King of Elecraft Spare Parts posted me a new DSP
processor board, it was plugged in, and all is now well.

Lessons learned:

1.  Be careful of using too much solder on female connectors.  The
solder can wick down inside them and make it very hard to push in the
mating plugs.

2.  While it is usual, when making modifications, to sacrifice a part
when removing it from a board, some high quality sidecutters are razor
sharp and their steel is very hard.  They can easily damage board traces.

I wish to thank the various members of this list, Lyle KK7P, Dave K4DGW,
  and Don W3FPR who have given me valuable advice and also staff at
Elecraft, particularly Gary Surrency and Scott King, for their support
and prompt service.  In thirty or so years of hamming, I have never
encountered such high quality product backup as what I have received
from this company.

73
Kevin
VK3DAP / ZL2DAP
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