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

[Don Wilhelm]

Jim,

On the setting of 8R HOLD, are you exiting the menu after making the 
change?  (tap MENU twice).

You may want to look at the RF board schematic sheet 3.  All the 
capacitors around U1 (The IO Controller) can be checked for proper 
values (most are .001uF marked 102). Also check that they are all in the 
proper holes (and not through an adjacent via hole).

How are you switching directly from 10m to 20m?  With the BAND+/BAND- 
buttons, you must cycle though 15 meters going between 20m and 10m, so I 
am a bit confused by your statement.   If you are using a software 
application to switch, remove it and test from the K2 buttons.

73,
Don W3FPR

On 7/1/2019 1:04 PM, Jim KO5V wrote:
> Hi Don,
>
> OK, the rig is S/N 7225. No KDSP2 is installed. I'm using an external CLRdsp box and speaker. The rig has been working very well; I've received many good signal reports. The DSP , AUX I/O, antenna and mic are all disconnected. I can hear this on the K2's internal speaker as well.
>
> I accessed the menu, and set it to 8R Hold. Then, each time I access that menu, it shows 8R nor, so I'm not sure if the setting isn't "sticking", or that it just resets each time it is accessed (or maybe I don't know what I'm doing).
>
> Q23 measures 0V, 0V, 7.9V (8V nominal), which is what the manual says.
>
> These pops are not clicking relays. They are in the audio, and might have always been there. I started using VFO B on 15M to check 20MHz WWV, so I just noticed the issue. The loudest pop happens when switching from 15M VFO B to A (but not A to B). None of the other bands do this. It's also rather pronounced when switching into and out of the bands on each side of 15M.
>
> Maybe it's just one of those "it just does that" situations, but it seems a bit strange to me that it is only on one band. I do hear a faint one when switching between 10M and 20M, but it's not at all obnoxious.
>
> Thanks again. 73,
>
> Jim KO5V
>