[Elecraft] K3: KPA100 Squeal

[Geoffrey Mackenzie-Kennedy]

Geoff,

It struck me when the squeal was first mentioned that something might be 
arcing over.  If I understand correctly the squeal appears only when the 
100w TX amp is - which narrows the search if arcing is the cause.

If the 12 KHz squeal is present only when a tic is generated, and if arcing 
is the cause of the squeal, then a possible reason why this occurs is that 
the voltage in some circuit is ramping up to a voltage every 270 msec 
sufficient to cause something to arc over, which is heard as a tic plus 
squeal.

It might be worth looking inside your K3 in a dark room.

73,
Geoff
GM4ESD


On Friday, July 01, 2011 at 6:24 AM, Geoff Wolf AB3LS wrote:

> This is a brand new K3 that I assembled about a month ago. The Serial 
> Number
> is 5517.
>
> I have been using an Astron SS-25A power supply with this which is indeed 
> a
> switcher. I have a battery that I'll be hooking up to it to see if this is
> still a problem.


>> On Thu, Jun 30, 2011 at 1:52 PM, W5UXH <Chuck.Broadwell at gmail.com> wrote:
>> > I looked at the MP3 file using Goldwave.  It appears to me that the "12
>> KHz"
>> > component is present only during the tics, not continuously.
>> >
>> > The tic period is roughly 270 msec (I have no idea what the tic is of
>> > course).   I zoomed in to a single tic (see PDF of images at the link
>> > below).  It appears that each tic has a very distinct pattern seen in 
>> > the
>> > individual samples which I suspect is the 12 KHz energy.