[Elecraft] K2 BFO CW alignment question

[Don Wilhelm]

Mark,

Analyzing the switch matrix is an iterative process
The first thing to do is to determine which wrong responses are being 
sent, and for that you must refer to the schematic.  In your case of the 
REV button and the STP 60 display, the hold of the REV button is 
bringing up the PF1 display.
Check the TAP function of the same button (AGC) to see if it brings up 
the RIT announciator (I think it will).
If so, it means that the D1 and D2 lines are somehow being activated at 
the same time.
Your first check would be to see if there is continuity between pins 12 
and 13 of U2.  Also check for continuity to ground for both of those 
lines.  If you find U2 pins 12 and 13 shorted together, look for the 
reason - a solder splash making a bridge or a bit of wire lead stuck 
between the pins, look top and bottom of the board.
That is how the process goes - as I indicated, it is not 'nice'.

Hopefully those two buttons are the only ones involved.
At worst, it means removing the pushbuttons and replacing them with 
new.  If it comes to that, clip the leads on the switch side close to 
the switch body and remove the leads one at a time, then troubleshoot 
the board.

73,
Don W3FPR

On 6/10/2018 7:15 PM, Mark Petrovic wrote:
> Thanks, Don.
>
> Would you mind outlining the approach for analyzing the front panel switch matrix?
>
>
>