[Elecraft] K2 issue

[Vic K2VCO]

Don Wilhelm wrote:
> Vic,
> 
> Troubleshooting rule #1 - Suspect what you touched last, and resist the 
> temptation to jump to conclusions.
> 
> I would first suspect a voltage drop at the rigrunner (and its fuse) 
> rather than a failed PA transistor.  Check the voltage at the K2 end 
> under full current load.

Did that. It was 13.1v as shown on the K3's internal meter. This was the same before and 
after the 'event'.

> Your 2.15 Amps at 10 watts seems about right, so that is not evidence 
> enough to declare a bad PA transistor.  I suggest that you remove the 
> KAT2 (if installed) and operate the K2 directly into a known good 50 ohm 
> dummy load before drawing any other conclusions.   Test with 13.7 to 
> 13.9 volts at the K2.
> 
> You could have a wattmeter anomaly, or if no wattmeter, the load may not 
> be exactly 50 ohms.

OK, I'll try it. I have a good dummy load and a scope to check the power. Can I set the 
KAT2 to CALP or do I have to completely remove it?

> If after taking those steps you still have less than 12 watts output 
> (10w on 10 meters), then it is time to check the RF voltages (with the 
> power set to 5 watts) at the Q5 and Q6 collectors. bases of Q7 and Q8, 
> and the antenna jack and compare those to the values shown in the 
> Transmit Signal Tracing portion of the manual.  If those are correct and 
> your maximum power output is still not up to par, then you can suspect 
> the PA transistors.

OK.
-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco