[Elecraft] K2 BFO CW alignment question

[Mark Petrovic]

Don, thank for the excellent guidance.  I'll begin the debug process.

By the way, I have eliminated spurious contact between the encoder board
and control board, as I debugged that some weeks ago:
https://www.mail-archive.com/elecraft@mailman.qth.net/msg219585.html.
There is now room between the boards such that the plastic packing material
you mention moves freely about without friction.  This spurious contact
possibility was one of the first things I checked today when the "c"
indicator would not light.

On Sun, Jun 10, 2018 at 4:43 PM, Don Wilhelm <donwilh at embarqmail.com> wrote:

> 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?
>>
>>
>>
>>
>


-- 
Mark