[Elecraft] K2 BFO issues

[Anthony Clare]

Hello:

I am not at home to try, so I will have to check R98 later. I remember fitting
the encoder and it was definitely a tight fit. I used a dremel sanding drum to
almost completely flatten the pins in the affected area on the encoder board
and control board. Then I reflowed all the connections that I flattened and
placed fiberglass tape over the encoder board. Once I did this, I could look
between the boards and see no physical contact. 

I will separate the control and front panel boards and see what happens when I
get home.

Thanks,
Anthony
n3kcb

------ Original Message ------
Received: Tue, 30 May 2017 08:51:03 AM EDT
From: Don Wilhelm <donwilh at embarqmail.com>
To: Anthony Clare <n3kcb at usa.net>, elecraft at mailman.qth.net
Subject: Re: [Elecraft] K2 BFO issues

Anthony,

When you put the K2 into CAL FCTR mode, what is the voltage at the ends 
of R98 (on the bottom of the board).  I am interested only in the 
highest voltage.

With the new K2s (those using the new encoder board), many strange 
problems are caused by contact of the encoder board with the Control Board.
You must flush trim the leads on the encoder board - and I mean almost 
right down to the board level.
Also you must flush trim the back of the Control Board in the area that 
could come in contact with the encoder board.
Make sure the rubber bumper pads are in place at the top corners of the 
Front Panel Board.

As a test, remove the 2 screws that secure the Control Board to the 
Front Panel and tilt the top of the Control Board to the rear.  If 
things then behave normally, you can be certain that contact between the 
encoder board and the Control Board is causing the problem.

73,
Don W3FPR

On 5/30/2017 8:07 AM, Anthony Clare wrote:
> Hello:
> 
> Looks like I am not the only one to have this problem. Just finished
assembly
> phase 2(?) on the K2. It was during the BFO tests that I realized there was
> not enough signal at the test point for the internal counter. I checked for
> poor solder, improper varactor diode install, verified that L33 was intact
and
> not being shorted by the 5 meg resistor, etc. I ran one crystal at a time,
but
> neither one would provide the proper signal level alone. I even checked L33
on
> the inductance meter and it came out to about 39uH, which seems about right.
I
> assume the inductance meter has some error. The resistor measures out to
about
> 5 meg.
>