[Elecraft] K2 bandwidth modification issue --- Success!-----

[Steve Garwood]

Don,

I pulled the KSB2 board again and ran through the connections between the
crystals with the ohmmeter.  I found a short to ground between X5 and X6
that should not have been there.  I ended up pulling the two crystals.  I
found a small piece of copper lifted on the board, shorting the crystal can
to ground on X5.  Operator error on this one.
Reassembled, and now I have the desired wider bandwidth on OP1.

Thanks for the jump start on a troubleshooting path.  I was already looking
past the possibility of error and seeking an alignment sequence.  Attention
to detail being the order of the day, things are in good shape once again!

73,
Steve, N0CZV



Steve,

How does the OP1 filter passband look when viewed on Spectrogram? It should
show a nice flat passband.  If it has a dip or valley in it, look for a bad
connection on one of the capacitors or crystals.

What is the possibility that you damaged one of the thru-plated holes when
removing the old crystals and capacitors.  Use the schematic to determine
'which is connected to what' and check all those connections with your
ohmmeter.

You may also have a problem with T1 or T2 soldering or a poor solder
connection in the switching diodes or R-Paks.  Re-flow the solder in those
areas with a hot (750 degF) soldering iron.

73,
Don W3FPR

On 2/10/2014 2:30 AM, Steve Garwood wrote:
> Hello!
>
> I am working on a K2,  <3000 s/n in which I installed the K2 SSBCAPKT
along with the 14 crystal kit.
>
> Receive is working, audio level is low on the OP1 filter, normal on FL1,
etc.
> I have transmit, with good audio, however, no measurable power output or
ALC reading.
>
> I've been searching for something similar to this, no luck so far.....
>
> It seems that the filter output is low, but functioning.....  Alignment
addresses adjusting BFO frequency, but nothing about output level.
>
> I checked soldering again, but I have not made it any further than
this....
>
> Any ideas?
>
>


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