[Elecraft] K3: KPA100 Squeal

[Guy Olinger K2AV]

If you can do it, see if you still have the noise running off a
battery.   73, Guy.

On Mon, Jun 27, 2011 at 8:37 PM, Adi Andrei <e.adi.andrei at gmail.com> wrote:
> The fans are still but I still hear it. Almost like some switching PSU
> noise.
>
> Adi
> 2e0ttx
>
> On 27/06/2011 15:21, Guy Olinger K2AV wrote:
>>
>> Check to make sure that the cables routed in front of the fans are not
>> touching.  A light touch will result in a sound like that.  It will
>> change or go away with the fan speed.
>>
>> 73, Guy.
>>
>> On Mon, Jun 27, 2011 at 9:10 AM, Adi Andrei<e.adi.andrei at gmail.com>
>>  wrote:
>>>
>>> I have the same thing happening, similar series K3 (5k something) , also
>>> assembled in March.
>>>
>>> Adi
>>> 2E0TTX
>>>
>>>
>>> On 27/06/2011 13:38, Joe Harris wrote:
>>>>
>>>> I have very similar symptoms in my K3/100 (SN 5284) that I assembled in
>>>> March. It makes the sound even if I am in TX test mode. Again, no
>>>> performance issues, just a slightly bothersome squeal / whine.
>>>>
>>>>
>>>>
>>>> On Sun, Jun 26, 2011 at 8:23 PM, Geoffrey
>>>> Wolf<liltechdude13 at gmail.com>wrote:
>>>>
>>>>> First off it was a great Field Day and my new K3 impressed me extremely
>>>>> not
>>>>> only in performance but in it's functionality.
>>>>>
>>>>> To kick off Field Day I installed a new KPA100 into the K3. I did all
>>>>> the
>>>>> necessary TX gain calibrations using a dummy load.
>>>>>
>>>>> One thing I noticed immediately was that I was hearing a very high
>>>>> pitched
>>>>> squeal coming from either the PA board or possibly the KIO3 (the board
>>>>> the
>>>>> amp plugs into). The squeal seems to vary in frequency each time the
>>>>> transmitter keys up (can only hear it when the radio is in TX). The
>>>>> squeal
>>>>> is not very loud but its loud enough for me to hear it if I listen
>>>>> closely.
>>>>> It doesn't seem to be power related. The squeal is there even if the
>>>>> radio
>>>>> is in TX but no power going out (RF Pwr set to 0W). The closest thing I
>>>>> can
>>>>> compare the sound to is perhaps a tiny leak in an air hose. Is this
>>>>> typical
>>>>> of a bad solder joint or something?
>>>>>
>>>>> This squeal only pertains to the new KPA100 installation. Before the
>>>>> amp
>>>>> was installed I didn't hear a thing.
>>>>>
>>>>> I should also note that nothing appears to be affecting performance.
>>>>> Puts
>>>>> out 100 watts no problem. Clean modulation, etc.
>>>>>
>>>>> --------------
>>>>> Geoffrey Wolf
>>>>> AB3LS (Amateur Radio Callsign)
>>>>> University of Pittsburgh '14
>>>>> grw20 at pitt.edu
>>>>> Liltechdude at me.com
>>>>>
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>