[Elecraft] [K2] No Transmit Power

[Brian Denley]

Don:
I am officially stumped.  I cannot find the fault in my transmit circuit but
that is basically do to my inability to accurately measure ANY RF voltage.
The RF probe doesn't seem to function.  I have replaced the resistor and
resoldered all the connections twice now but I continue to read betwen 50
and 70 mV with any handheld DMM and basically nothing with an HP3478A,  I am
using the DC volt setting.  And all that 50 to 70 mV is across the 4.7Mohm
resistor on the probe board.  This reading masks almost anything I am trying
to measure and without that capability, I am at a loss trying to trouble
shoot the transceiver.  Connecting the ground lead to the probe still leaves
me with the same reading.

Is there any other instrument that I can buy or borrow that will accurately
measure small RF voltages?  Can I buy a working RF probe from  Elecraft?
Are there only certain DMMs that it will work with?

Again, the receiver section and the panel and control functions work just
fine but I only get about 0.5 mW on the readout with keydown.
Brian Denley
http://home.comcast.net/~b.denley/index.html

 > Brian,

>Yes, I am sure about the 4.7 Megohms, but your 4.6 meg resistor will do
>just as well.
>It is DC voltage through the resistor, and it scales the peak RF voltage
>down to approximate RMS.
>Look at the schematic for the RF Probe on page 9 of Appendix E in the K2
>manual.

>With the RF Probe, you will be able to measure RF voltages down into the
>millivolt region.
>Go through the steps listed in Appendix E of the manual under Transmit
>Signal Tracing.

>When you get to the points to measure on page 14 (assuming you do not
>find a problem with the VFO or BFO), the RF voltages will be HIGHER than
>the expected value because you do not have enough transmit output.  What
>you are looking for is the first point where the RF voltage is LOWER
>than the expected value.  That point is just beyond the failing stage,
>and you will know which stage to examine in detail.

>Only after your K2 is operating properly for RF output will you see the
>expected values - go with the higher or lower criteria.

>Don