Re: K2 BFO test failed

Posted by Don Wilhelm on Sep 30, 2017; 1:57pm
URL: http://elecraft.85.s1.nabble.com/K2-BFO-test-failed-tp7634802p7634804.html

Mike,

The inadequate BFO range is usually a result of the L33 toroid leads not
being well soldered.  The toroid wires are very fine and sometimes are
not visible to the naked eye, so use magnification to examine them.
When re-soldering, use a pointed tool to bring the fine toroid wires
down onto the solder pad instead of further up on the securing resistor
lead.

For adjusting the 4 MHz Reference Oscillator (that has nothing to do
with the BFO range), refer to the K2 Dial Calibration article on my
website www.w3fpr.com for the most accurate method of adjusting the
Reference Oscillator.

Be aware that the 4 MHz Reference oscillator can drift in normal
operation, so soon after adjusting it, run CAL PLL and CAL FIL while it
is still "on frequency".  That oscillator is not used in operation for
the K2 frequency display.  In other words, simply adjusting the 4 MHz
Reference does nothing for normal operation.

73,
Don W3FPR

On 9/30/2017 9:35 AM, Mike Maiorana wrote:

> Hello all. I have a K2, 6000+ serial number, that I'm trying to get working
> correctly. Unknown history. A quick test showed the filters were not
> properly adjusted (could hear both sidebands of carrier on some bands). I
> thought it would be best to do a top-down alignment.
>
> I adjusted the 4 MHz oscillator, verified the PLL reference oscillator
> range (12.43 kHz), VCO test and VCO alignment. No problems up to that
> point.
>
> I'm having an issue at the BFO test. The BFO high frequency is 4916.04 kHz
> and the low frequency is 4913.82 kHz. That's a difference of 2.19 kHz, well
> below the 3.6 kHz stated minimum.
>

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