[Elecraft] K2 Alignment & Test Part II

[Don Wilhelm]

Neil,

Your readings on the PLL range test show that Q19 is marginal.  Q19 is 
not oscillating properly at the high end of the PLL range.

The first thing to try is a small capacitor (12 to 15pF) from the source 
of Q19 to ground.  You can easily mount the capacitor between pins 1 and 
12 of U4.  You can use one of the capacitors from the K2 kit and request 
a replacement from support at elecraft.com

If that does not allow proper frequencies for the PLL Range Test, then 
get a replacement Q19 from parts at elecraft.com.

Merry Christmas everyone.

73,
Don W3FPR

On 12/24/2019 6:19 PM, Neil Zampella wrote:
> Hi,
> 
> Started to do the Align/Test Pt II, and properly saw the correct
> frequency of 12090 +/- 30 kHz.   Tried the next part to adjust the
> Reference Oscillator using my other K2 as the receiver and was able to
> hear the oscillator at 3999, but C22 would not adjust to a
> zero-beat.     OK ... so it was close for the time being, so I figured
> I'd use my KX3 to verify it later.  Moved on to the range test.   The
> Band- and Band+ buttons did not affect the display.
> 
> Dug into the list archives, and saw a number of messages from Don to
> check the solder joints, alignment, and type of D16, D17, R19, and
> L31.    I realized that somehow I missed installing R19.   So I
> installed the resistor, then restarted the alignment.   This time when I
> switched to CAL FCTR, the rig did not display the expected frequency of
> 12090, but  a frequency of 3560 or so, flickering between readings.
> However, when I pressed the Band- button, it changed to a steady 12084,
> but when the Band+ was pressed, back to the 3560 flickering.
>