KPA1500 Power Supply noise

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KPA1500 Power Supply noise

aa4vt
My KPA1500 Power Supply is making a noise that has gotten progressively
louder over time when I transmit. It sounds like a hissing (but it is not
arcing) when I transmit. The noise is modulated by SSB speech or CW or
digital modes keying, louder at higher power levels now during the CQWW WPX
Phone contest.

I am pretty sure it is not RF getting into the Power Supply. I have
followed K9YC practices of bonding the K3, KPA1500 Power Supply and RF
decks to the ground bus. All cables going into and between are wound on
snap on or toroid ferrites.

Has anyone else run across this? I plan to open up the power supply and
check for loose parts and do some more testing after the contest.

--
Thank you!
David Needham, AA4VT (formerly K4AJA and K8AJA)
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Re: KPA1500 Power Supply noise

N4ZR
Not heard here, although my KPA-1500 gets fairly heavy use.  Power
supply is on the floor, which no doubt helps with noise.

73, Pete N4ZR
Check out the new Reverse Beacon Network
web server at <http://beta.reversebeacon.net>.
For spots, please use your favorite
"retail" DX cluster.

On 3/27/2021 11:06 AM, David Needham wrote:

> My KPA1500 Power Supply is making a noise that has gotten progressively
> louder over time when I transmit. It sounds like a hissing (but it is not
> arcing) when I transmit. The noise is modulated by SSB speech or CW or
> digital modes keying, louder at higher power levels now during the CQWW WPX
> Phone contest.
>
> I am pretty sure it is not RF getting into the Power Supply. I have
> followed K9YC practices of bonding the K3, KPA1500 Power Supply and RF
> decks to the ground bus. All cables going into and between are wound on
> snap on or toroid ferrites.
>
> Has anyone else run across this? I plan to open up the power supply and
> check for loose parts and do some more testing after the contest.
>
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Re: KPA1500 Power Supply noise

Steve Hall
In reply to this post by aa4vt
Regarding placement of the KPA1500 power supply.
After repairing and maintaining residential home computers professionally
for several years, be advised that floor placement will allow 5X the dust
to be sucked into the unit.  Units with air flow in and out are like vacuum
cleaners.  I recommend raising the unit, even if only a foot or two, to
reduce dust intake.  Units on the floor were packed with dust as compared
to units on desks.
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Re: KPA1500 Power Supply noise

Vic Rosenthal
I used to maintain computers used by farmers. I’m surprised they didn’t plant crops in them. There was enough soil there. Floppy disks (this was a long time ago) were unusable due to the abrasive action of the dirt.

Victor 4X6GP

> On 28 Mar 2021, at 4:24, Steve Hall <[hidden email]> wrote:
>
> Regarding placement of the KPA1500 power supply.
> After repairing and maintaining residential home computers professionally
> for several years, be advised that floor placement will allow 5X the dust
> to be sucked into the unit.  Units with air flow in and out are like vacuum
> cleaners.  I recommend raising the unit, even if only a foot or two, to
> reduce dust intake.  Units on the floor were packed with dust as compared
> to units on desks.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
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