OT: Audible hum from Astron linear power supply. Fixable?

[Barry]

I have an Astron RS-70M that I use to power the station.  It on the carpeted floor under a desk.  It's probably 30 years old now.  I've been inactive for several months, so it's been off all summer.  Now when I turn it on, it has an annoying, low-pitched audible hum.  All the screws are tight, though when I press down on the top of the case, it goes away.  Any thoughts on how to quiet it down?
Tnx,
Barry W2UP

[Elecraft mailing list]

Take the cover off and loosen the transformer mounting bolts and slide a piece of cardboard under each corner and see it that cures the vibration.  Mine did that and it fixed it.

Mel, K6KBE



On Sunday, September 14, 2014 7:01 AM, Barry <[hidden email]> wrote:
 


I have an Astron RS-70M that I use to power the station.  It on the carpeted
floor under a desk.  It's probably 30 years old now.  I've been inactive for
several months, so it's been off all summer.  Now when I turn it on, it has
an annoying, low-pitched audible hum.  All the screws are tight, though when
I press down on the top of the case, it goes away.  Any thoughts on how to
quiet it down?
Tnx,
Barry W2UP



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[Phil Wheeler-2]

I have an AL-811H amp that does that. I put a
couple of bricks on the top of it when it was in
use (now have KAP500) and that cured my AL-811H :-)

Phil W7OX

On 9/14/14, 6:58 AM, Barry wrote:

> I have an Astron RS-70M that I use to power the station.  It on the carpeted
> floor under a desk.  It's probably 30 years old now.  I've been inactive for
> several months, so it's been off all summer.  Now when I turn it on, it has
> an annoying, low-pitched audible hum.  All the screws are tight, though when
> I press down on the top of the case, it goes away.  Any thoughts on how to
> quiet it down?
> Tnx,
> Barry W2UP
>
>

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A stack of about a year's worth of QST magazines placed atop the power
supply does the job here. I believe other magazines would also work.

73, Dale
WA8SRA

> I have an Astron RS-70M that I use to power the station.  It on the
> carpeted
> floor under a desk.  It's probably 30 years old now.  I've been inactive
> for
> several months, so it's been off all summer.  Now when I turn it on, it
> has
> an annoying, low-pitched audible hum.  All the screws are tight, though
> when
> I press down on the top of the case, it goes away.  Any thoughts on how to
> quiet it down?
> Tnx,
> Barry W2UP
>
>
>
> --
> View this message in context:
> http://elecraft.365791.n2.nabble.com/OT-Audible-hum-from-Astron-linear-power-supply-Fixable-tp7593065.html
> Sent from the Elecraft mailing list archive at Nabble.com.
> ______________________________________________________________
> Elecraft mailing list
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> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to [hidden email]
>

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[Barry]

[e-mail] wrote

A stack of about a year's worth of QST magazines placed atop the power
supply does the job here. I believe other magazines would also work.

Thanks for the suggestions.  Will this work if I bring up the electronic edition of QST on my laptop and put the laptop on top of the power supply?
73,
Barry W2UP

[Phil Wheeler-2]

Only if your laptop is a very old and heavy one :-)

Way back I had one heavy enough!

Phil W7OX


On 9/14/14, 5:27 PM, Barry wrote:
> [hidden email] wrote
>> A stack of about a year's worth of QST magazines placed atop the power
>> supply does the job here. I believe other magazines would also work.
> Thanks for the suggestions.  Will this work if I bring up the electronic
> edition of QST on my laptop and put the laptop on top of the power supply?
> 73,
> Barry W2UP

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[Bill Turner-2]

------------ ORIGINAL MESSAGE ------------(may be snipped)

On Sun, 14 Sep 2014 18:42:35 -0400 (EDT), Dale wrote:

>A stack of about a year's worth of QST magazines placed atop the power
>supply does the job here. I believe other magazines would also work.
>
>73, Dale
>WA8SRA

REPLY:

One must be careful which year QST one uses. Years ago QST had a
smaller format and would probably require a year and a half.  :-)

73, Bill W6WRT
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[Wes (N7WS)]

The smaller format issues had technical content in them that made them worth
saving.  The more recent issues are so lacking in content that after about 20
minutes of looking for something worthwhile, into the trash they go.  Saves on
shelf space.

Wes  N7WS


On 9/14/2014 6:28 PM, Bill Turner wrote:

> ------------ ORIGINAL MESSAGE ------------(may be snipped)
>
> On Sun, 14 Sep 2014 18:42:35 -0400 (EDT), Dale wrote:
>
>> A stack of about a year's worth of QST magazines placed atop the power
>> supply does the job here. I believe other magazines would also work.
>>
>> 73, Dale
>> WA8SRA
> REPLY:
>
> One must be careful which year QST one uses. Years ago QST had a
> smaller format and would probably require a year and a half.  :-)
>
> 73, Bill W6WRT
>

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[k6dgw]

Sep "DX Issue" has precious little about DX.

Re Astron:  Many people have very good results with them, there are many
on mountain tops in the Cactus Intertie system that have run for
decades.  My experience isn't so good, maybe just bad luck, but I've
given up on them although I've never noticed an audible hum.  Then
again, I'm fairly deaf which can sometimes be an asset. :-)

Power supplies are those things that just sit there and hold down the
desk or floor against gravity outages and I'm looking for reliability.
My station is currently powered by a Yaesu 1030A that came with the
FT-847 close to 15 years ago.  It produces 14.3 V all the time,
regardless of load, and basically, that's all it does [we haven't had a
gravity outage in that time].
73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org  I've also had good results from Triplett supplies.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org

On 9/14/2014 7:56 PM, Wes (N7WS) wrote:
> The smaller format issues had technical content in them that made them
> worth saving.  The more recent issues are so lacking in content that
> after about 20 minutes of looking for something worthwhile, into the
> trash they go.  Saves on shelf space.
>
> Wes  N7WS


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