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 ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
