[Elecraft] KPA500 Heat Expansion Pop

[n5ge at n5ge.com]

All,

I don't have the noise you describe, but it's logical to me that if the bolt
that goes through the center of the transformer has any slack in it, it might
cause a click or thump when cooling or heating.  That may be why Elecraft used
the bell washer under the bolt head to allow expansion and contraction of the
transformer during operation.  

Check the nut on the bottom side and see if you can pass a piece of paper
between the bottom reinforcement plate and the nut while the power supply is
cold  Don't hold it upside down while you do this.  If you can, the nut is not
seated.  It's easy to accidentally leave a self locking nut loose, due to the
torque resistance from the locking material in the nut.

Hope that helps.

73,
Tom
Amateur Radio Operator N5GE
ARRL Lifetime Member
QCWA Lifetime Member

"If somebody has a bad heart, 
they can plug this jack in at 
night as they go to bed and it 
will monitor their heart 
throughout the night. And the 
next morning, when they wake up 
dead, there'll be a record."

--Mark S. Fowler, FCC Chairman,
  1981 - 1987


On Thu, 8 Dec 2011 12:37:37 -0500, Joe Word <joe.n9vx at gmail.com> wrote:

>My KPA500 has developed a heat expansion pop. When it heats up and
>then cools down I get a pop from inside the amp. It does this now
>every time I make a SSB transmission.
>
>Anyone else experience this? If so, any resolution?
>
>Joe  N9VX
[snip]