Dave, G3YMC wrote: The volume pot track is well known to become noisy over time, but the same applies to all four pots. My CW speed pot (K2 2498) is now quite touchy with only a very small change causing a significant change in speed, and the RF gain pot (normally left at the clockwise endstop) is also showing signs of noisiness. Any noise on the speed and power pots will be interpreted by the DACs and cause the transient display change we are all seeing.
--------------------------------------------- In general the audio pots on the K2 don't have a noise problem Dave. The original design of the K2 audio gain circuit put demands on the audio pots they weren't designed for which gave the impression that the pots were going bad in early K2's. Wayne redesigned the circuit and I haven't heard about any problems with noisy controls since. In early K2's, the audio gain control acted as a shunt resistor across a balanced audio line. That required that the pot have essentially zero resistance at minimum. Most pots are not designed to provide that reliably, including the one used in the K2. After a short period of use, the pot would start showing a small amount of resistance near minimum, which made it sound "noisy" and sometimes made it impossible to shut the audio off at minimum. I modified my K2 with Wayne's new circuit four years ago and I've not had a noisy pot problem since. The change was incorporated into the basic K2 some time after the mod was developed because it required changes to the PC boards, so there were a lot of K2's built with the old circuit. I think the change came about around S/N 3000 somewhere. From the comments I've seen, many owners never got around to modifying their units once they had gotten used to the control sounding noisy near minimum volume. If yours hasn't been modified, there are instructions for doing that under "builder's resources" on the Elecraft web site. Look for "K2 AF Pot Application Note". Ron AC7AC _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
