Tom,

That hum is probably caused by vibration of the metal case.  You may be able 
to fix it by pushing on the cover, or by removing the cover and putting it 
back on again.  Then again, it may just remain the same.  I wouldn't leave 
that padding underneath the supply; it's probably blocking air flow around 
the case, which may cause unwanted heat build-up, which will give you a far 
worse problem than the mechanical hum you're hearing.  Of course, you could 
always mount the power supply on the outside of the motor home and drill 
holes for the wires.  You wouldn't hear the hum, but you might not like the 
wind and other weather elements coming through the holes.

Steve


Steve

----- Original Message ----- 
From: "tom behler" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, August 24, 2010 21:42
Subject: Noisy Astron RS35 power supply


> Hi, all.
>
> I don't know whether it's because of being jolted around in the move or
> what, but my trusty metered Astron RS35 power supply seems noisier than it
> used to be.
>
> It still works fine, but seems to have a louder hum than it used to have.
>
> I have it set up in exactly the same way I did out in Colorado, on the top
> shelf of a sturdy ham operating desk.  I even put some padding underneath
> the supply, but it really didn't seem to do much.
>
> I suppose I could take the cover off, and try to feel around to see what
> might have happened, but I know there are some electrolytic capacitors in
> there that would not make for a pleasant experience if they were
> accidentally discharged.
>
> If anyone has had this experience, and has any suggestions, please let me
> know.
>
> Again, the supply still works fine;  it just lets me know it's around more
> than it used to.  (smile)
>
> 73 from Tom Behler:  KB8TYJ
>