[Elecraft] K1 Issue. Lost reception when transmitter stage completed.

[Don Wilhelm]

Les,

You did not mention your test gear nor any information about your setup, 
so I have to make some guesses and ask some groundwork questions.

Are you injecting RF from a signal generator to the BNC jack?  If so, is 
that signal large enough to register on what you are using to determine 
signal or no signal ('scope with 10X probe or RF Probe)?
Do you have the jumper installed in J2 of the band board?

Turn the signal generator off, then on while observing the level at band 
board J8 pin 8 - you should see a rise in the RF being measured.  If 
not, the signal level is too low to register on your measurement device.

The Signal Tracing section starting on page 5 of the K1 manual appendix 
gives you an orderly sequence for troubleshooting.  Where does the 
signal level drop below the expected level?  That point is just past the 
point of failure.

73,
Don W3FPR

On 8/22/2014 1:03 PM, Les Garwood wrote:
> Dear Fellows,
>
> I just finished construction of my K1.  The receiver stage worked perfectly
> until I finished the transmitter stage.  I still get audio hiss and volume
> but no signal on any band, AGC on or off, attenuator on or off.
> All the voltages and resistances check out except the anode of D9,
> according to the manual, is supposed to be > 100k.  I'm sure this is an
> error, however,  since the DC path to ground from that point goes through
> three resistors and a choke totalling only about a couple K,  which is what
> I measure.
> I still get rf out of the VFO, and can trace it through the filter board,
> J6, at pins 1,2 and 6, with my scope.  However,  there is no trace of
> signal rf from the antenna on pins 1 or 8 of J7.
>
> I have no rf at the attenuator relay either, at pin 3, or any other.
>
> I can't quite figure out yet how the TR switch circuit works (or doesn't
> perhaps) so it's hard to troubleshoot if it is the problem or not.
>
> Needing the filter board in place makes trouble shooting all the harder
> too.  I wish I had a layout view showing the bottom of the rf board to help.
>
> As always, any comments welcome and appreciated.
>
>