[Elecraft] K2/100 Transmit shut down

[Don Wilhelm]

Art,

Normally, PA HOT and Hi REFL are 2 different things.
For the PA HOT, let the KPA100 cool to ambient temperature and then 
power it on and check the K2 CAL TPA menu setting - it should be the 
room temperature in degC. (normal room temperature is about 23 degC).  
If it is much different than that value, set it to the ambient temperature.

As for Hi Refl - do you get the same indication working into a dummy 
load (I know you specified a dummy load, but I am covering all bases)?  
If not, then you may want to investigate what has changed in your 
antenna system.
OTOH, if you get Hi Refl on the dummy load, then the most likely cause 
is that the KPA100 wattmeter diodes have been damaged.  The most likely 
cause is a static discharge from wind, rain, or nearby lightning while 
the antenna is connected.

I would first replace D16 and D17 in the KPA100 and see if the problem 
is corrected.  In most cases it will be.

After that, you can help "close the barn door after the horse got away" 
by making certain all your antennas have a DC path across the feedline 
to bleed off static - a 5k to 50k non-reactive resistor (2 or 3 watts) 
will do that job just fine - connect it across the feedline.  At the 
antenna feedpoint will work, but lacking that, place it inside an 
antenna switch in the shack.

Speaking of antenna switches, arrange your switches to connect the K2 to 
a dummy load or a short to ground when not operating.  If you have no 
antenna switch, then disconnect the antenna when not in use.

Yes, I understand that other transceivers do not have those 
requirements, but they do not have a sensitive wattmeter right at the 
output to detect the actual power output.

73,
Don W3FPR

On 6/23/2014 8:23 PM, Arthur Lewis wrote:
> *My k2/100 has just developed a transmit problem. In CW it cuts out when I
> drive it above 50 watts. It comes up with HI Reflected or PA Hot. I am
> using a dummy load and the SWR is 1.0. It sounds like I lost one of the
> finals, but wonder if anyone has had this problem. I built it in 1999 and
> the amp in 2000 and never had a transmit problem.*
>