[Elecraft] Fw: Re: K2: "Pop" when switching certain bands

[Jim KO5V]

Hi again,

I did as Don suggested, and checked the values of all of the capacitors around U1, and all of the band-switching relays. I also re-flowed all of their solder joints. With the bottom panels, top panel and the left-side panel off, the click in the audio was a lot better, and switching VFOs on 15M was quiet. However, after I put it all back together, it's all returned. I looked the the S-meter, and with the RF gain set fully cw, I see the following brief readings that accompany the clicks and pops in the speaker:

15M, VFO A to VFO B: S1;
*15M, VFO B to VFO A: S9;

15M-17M: S1;
17M-15M: click, no reading;

*15M-12M: S5;
12M-15M: click, no reading;

20M-30M: click, no reading;
30M-20M: click, no reading.

The other bands/VFOs switch quietly.

Otherwise, the radio seems to work just fine, and has been performing well. I recently set 15M VFO B to 20MHz WWV, and that's when I noticed this. I wonder if I should just forget about it, except the S5 and S9 pops just don't give me a good feeling.

How does the radio switch between VFO A and VFO B? I assume it's done in the firmware, but is some relay (or a band-specific relay) involved? 

Has anyone else with a K2 noticed something similar? Should I be looking somewhere else, or just move on?

Thanks, and sorry to keep obsessing about this.

73, Jim KO5V