[Elecraft] KPA500 Clicks & Pops

[Bob McGraw K4TAX]

Come to think about it, I haven't heard mine click and pop in quite some 
time.  I doubt that it's seasonal, but that is an interesting twist.  I 
doubt that my room or the dormant equipment varies over +/- 2°F over any 
given 24 hr period.

73

Bob, K4TAX

On 4/7/2019 1:11 PM, Andy Durbin wrote:
> This will only be of interest to a few KPA500 owners  - those who don't think loud clicks/ticks/pops are acceptable.
>
> In the message below I reported that I had lost interest in my investigation because the click/ticks had stopped.  That message is dated October 2018.   Late March the ticks came back and now, early April, they are back to the annoying level that I experienced in 2018.  What's different?  Room temperature and consequently the powered on but not transmitting temperature of the KPA500 is much lower in the winter months.
>
> Although I lost interest in the investigation I continued to record PA temperature, heat sink temperature, and Z bracket temperature for every transmission I made.  That's a lot of data but  differences between summer and winter operating conditions may be interesting.   I plan to pick a few mid winter samples to compare with a few peak summer samples.
>
> Has anyone else who is annoyed by KPA500 click/ticks noticed any correlation with room temperature?
>
> 73,
> Andy, k3wyc
>
>
> ________________________________
> From: ANDY DURBIN
> Sent: Tuesday, October 16, 2018 6:52 AM
> To: elecraft at mailman.qth.net
> Subject: KPA500 Clicks & Pops
>
>
> I found this quite annoying too.  My approach was to try to understand how the Z bracket temperature varied relative to the heat sink temperature.  I placed a thermistor on the front end of the Z bracket and another on the heat sink fin closest to the Z bracket.  I logged the standard PA temperature and these additional thermistor temperatures for every transmission I made (still do).   I established baseline temperature characteristics and planned to use this data to see if any mods I made changed the characteristics.
>
>
> Surprise!  -  When I though I had enough data to move on to the next step in the investigation it stopped clicking.
>
>
> Adding the thermistors only required removal of the front panel and the Z bracket screws were no touched.   It continued to click after the thermistors were added and then stopped a few weeks later.
>
>
> The data show the rapid change in temperature is at the PA sensor only.  The heat sink and Z bracket change much more slowly and never have a large temperature difference.  Their temperatures do cross over though.
>
>
> One problem with temperature logging is that I had no data, except for my test notes , on the clicks themselves.  I had planned to added some inexpensive sound detection modules and add this data to the logger.  That's on hold until the clicks come back.
>
>
> It's really nice not to have the amp click continuously on every FT8 transmission.  I wish I knew what fixed it.
>
>
> 73,
>
> Andy k3wyc
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