[Elecraft] K2 VCO Test pg 57: Problem -reading 0000 kHz

[k6se@juno.com]

I took some measurements in my K2, Chris.

At the source of the VCO source-follower transistor (Q18) I get RF
voltage readings of about 0.4 volts on all bands except 18 MHz and 28 MHz
where I get about 1.1 volts RF.

At the gate of Q18 I get about 0.7 volts RF on all bands except 18 and 28
MHz where I get about 1.9 volts RF.

I have no idea why the signal level is so much greater on 18 and 28 MHz. 
If this is normal, you might try those bands for checking the output at
TP1, because maybe the signal is so weak on your K2 (on 80m) that the
K2's freq counter won't trigger.

The frequency measured (using the K2's internal freq counter) at the same
points is the VFO dial readout frequency plus about 4915 kHz for the
lower bands and minus about 4915 kHz for 21 MHz and above.  These same
frequencies appear at TP1.

Pin 13 of U4 is 4.18 VDC on all bands with no apparent RF riding on it.

I was mistaken about U4 pin 6.  It stays at 5.0 VDC on my K2 regardless
of whether the display is on a menu item or not.  I haven't checked but
maybe its function is for CAL PLL where it goes low.

I'm assuming that your optical encoder (VFO knob) is working because you
obviously are tuning to 4000.10 kHz in the 80-meter band to measure the
output at TP1 per the procedure on page 57 (VCO Test).

73, de Earl, K6SE