[Elecraft] K2 Alignment & Test Part 1

[Phil Wheeler]

Have you sold the movie rights to this screenplay?  ;-)

73, Phil

Joe - aa4nn wrote:

>My follow-up with Michael's suggestions.
>73, Joe, aa4nn
>
>Michael:  So, what do you have at pin 1 of U8?
>Me:  Pin 1 shows 5.1 volts with st l 255,  2.5 volts with st l 128
>
>Michael:   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.
>Me:  At RP7 pin 6 (drain?) is zero volts.
>
>Michael:  The signal from U8 pin 4 should be about 2.5 VRMS AC.
>Me:  zero volts
>
>Michael:  Toggle side tone source if this is not true.
>Me:  Toggle has no effect.  I left it at U8-4.
>
>Michael:  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.
>
>Me:  I inspected all around U8.  Some solder did not flow around some pins on the component side of the board.  I added solder to ensure flow through.  I will continue looking for bad connections.
>
>Michael:  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.
>
>Me:  U8-1 seems to be okay.  
>  
>