[Elecraft] K2 Alignment & Test Part 1

[Masleid, Michael A.]

Hi Joe,

>So it's back to the basics of examining the control board =
microscopically.

So, what do you have at pin 1 of U8?  This is the volume control for
side tone.  It should run from 0 to 5 volts DC or there about as you =
adjust
ST L from 1 - 255.  The voltage on the drain of Q5 will show about half
that if Q5 gate is driven with a square wave signal from U8 pin 4.

The signal from U8 pin 4 should be about 2.5 VRMS AC.  Toggle side tone
source if this is not true.

If U8 pin 1 is 0 Volts DC, and U8 pin 4 does not AC on it, and you have
met all of the menu conditions to get a side tone, start looking for bad
connections around about U8.

Note that if you inject a little DC current into the drain of Q5, you
should hear a pop in the speaker as you connect it.  A 47 K Ohm resistor
from the drain to the 5 volt supply should do it.  If you hear side tone
at that point, the problem is with the volume control out of pin 1 on =
U8.

73, de Michael, AB9GV