[Elecraft] [K1] Building a K1 no side tone

[Don Wilhelm]

Rick,

The K1 display changes to a simulated bargraph to indicate the power 
output when keyed.  You will not have any power output at this stage of 
assembly, so your statement of a 'blank display' may be just fine.  
Since the backlight stays on during keying, I should retract my 
statement about a power problem.

The most likely reason for no sidetone is soldering - check to see if 
all points are well soldered and none skipped.  You do have the AF Gain 
advanced do you not?  The K1 sidetone varies with the AF Gain setting.
The source of the sidetone is the output from the DAC on the Front 
Panel, U2 pin 1.  If you have an oscilloscope, you could check to see if 
you have an audio signal there when the K1 is keyed.  Lacking a 'scope, 
connect a pair of leads to an audio amplifier input (line in of a 
computer soundcard or an MP3/CD player) and probe at that point to see 
if there is any sound - it might not sound great, but you will know if 
the signal is present.
The signal leaves the front panel via J1 pin 5.  Look at the schematic 
for the RF Board sheet 1 in the lower left corner and you will see the 
components that the sidetone signal (XFIL/TONE) are applied to.  It 
makes it way to the AF Amp through the AF Gain control.  You should hear 
some 'white noise' sound when the AF Gain is advanced.  If the audio is 
totally silent, you may have a problem with the AF Amp rather than the 
sidetone.

73,
Don W3FPR

Rick/WA6ES wrote:
> I should of said I am on Page 36 of the Alignment and Test Part 1 so I think
> that there is no output, I will check the board anyway, you never know. At
> first I did find some points not soldered and took care of them. Still
> checking and killing brain cells.
>   Not sure if the display goes blank when you are transmitting or still
> displays the frequency that you are on. I was thinking ground or short but
> the backlight stayed on.
>
> Rick/WA6ES
>   
>