Anthony,
If you do not find more than 7 volts at the end of R98 that is furthest
away from Q24, then look at the U10A/Q8 circuit on the Control Board.
Check the associated components and their soldering. That is more
likely to be the problem than the active devices.
73,
Don W3FPR
On 5/30/2017 9:28 AM, Anthony Clare wrote:
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 <[email protected]>
To: Anthony Clare <[email protected]>, [email protected]
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.
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