My K2 suddenly quit supplying a sidetone. Changing sidetone level and frequency do nothing.
Per the troubleshooting guide, I've found that the drain of Q5 has no AC voltage when key down, while pin one of U10 (IIRC) is supplying 5 volts (and pin 25 of the IC in the previous step had expected 2.5v AC). So, this seems to mean that Q5 is bad, but when I pulled it and tested it with the M3 semiconductor analyzer, it is not obviously bad (to me anyway). It reads NMOS Vth=1.76v, S-G-D mA=1.13 - whatever that means, I don't know enough to interpret. Any off the cuff ideas? I have a replacement 2n7000 on the way, but still wondering why it would fail in circuit, and if its really bad. Thanks, Chip AE5KA ______________________________________________________________ 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
