Hi Dan, You might check the DC bias voltage on the current sense resistor near U7A. I would guess that it would be higher when the K2 Power is set above 10 watts then when it is set below. This shift might represent Emitter current acting somewhat normal.
Perhaps check the voltage difference between pin 6 of U7B and each base of the 2879s. These should not be too different from each other. I might check the resistance between pin 6 of u7B to GND and compare that to the 2879s Base to GND resistance. It should be a little more as you are adding in the bias resistors. Even with the 2879s in circuit I would try using my diode check on the 2879s emitter-base junctions, for the possiblity they can be read that way. At a time like this, one would surely like to have a schematic marked up with the good-known test voltages marked on it! Hope this helps, N1BBR ?Hello all, Is there a way to check the PA transisters in my K2 safely while still installed? Thanks in advance. Dan af4lb -- [email protected] ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
