[Elecraft] KPA500 clicking

[Wes (N7WS)]

More on this mystery.  The sound is also audible in the K3.  It is definitely 
mechanical and only happens (in both units) when the Aux cable is connected and 
the KPA is in Operate, in other words when it goes into or out of transmit.  The 
Speaker is Off in the K3, the sound is NOT audible in the headphones. It happens 
in either QSK or Semi.  I can also hear a single click when going into or out of 
Tune.

RF may be switched with PIN diodes, but there are some relays in there someplace.

This isn't, I suppose, a real problem; more of a curiosity and apparently, a 
test of reading comprehension.

Now, exactly where are those schematics located?

Wes  N7WS


On 12/29/2014 5:38 PM, Don Wilhelm wrote:
> Wes,
>
> The KPA500 T/R switching is all electronic, so no reed relays are involved.
>
> Are you certain the clicking noise is coming from the KPA500? There may be 
> some audio from the speaker/headphones from the K3 when returning to receive.  
> QSK OLD vs. QSK NEW might change the behavior unless it is truly coming from 
> the KPA500 (which would likely indicate some mechanical effect - likely due to 
> heating).
>
> The fact that you hear it in TX TEST mode indicates that it is not a heating 
> problem, but check closely to determine if it is actually in the K3 audio on a 
> return to RX from TX condition.
>
> 73,
> Don W3FPR
>
>
> On 12/29/2014 4:58 PM, Wes (N7WS) wrote:
>> I'm a relatively new owner of a KPA500. I'm also, thanks to the new K3 
>> firmware, using QSK for the first time in my ham career.
>>
>> These two facts have led to me hearing a slight clicking noise emanating from 
>> the amp that follows the keying. This is unrelated to drive or output power, 
>> since it happens in the TX Test mode too.  I understand that PIN diodes are 
>> used for RF switching but it still sounds like a reed relay to me.
>>
>> Any explanation?  (Hint) Having a schematic would probably make this self 
>> explanatory.
>>
>> Wes  N7WS
>> ______________________________________________________________
>