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Re: KPA500 Heat Expansion Pop

Posted by Don Wilhelm-4 on Dec 11, 2011; 12:35am
URL: http://elecraft.85.s1.nabble.com/KPA500-Heat-Expansion-Pop-tp7082519p7082572.html

I would be concerned that going from 5/16 inch to 3/16 inch may be too
much of a difference to assure that the screws have enough thread
engagement.  I would think going to 1/4 inch would be a better choice.

This sounds like a simple problem, and the real cause is that the holes
were not tapped deep enough, or that the tap had become worn at and was
not noticed in time - so several assemblies slipped through with
inadequately tapped holes.  This may be a problem for a few, and not a
universal problem.

Yes, the easiest disassembly is to remove the PA unit.  Not a major
chore, but yes, it is not trivial to get to those screws.

Don W3FPR

On 12/10/2011 6:35 PM, Joe Word wrote:

> Could we get more info on this possible fix, how much disassembly is
> required? Looks like the PA unit must come out?
>
> Joe  N9VX
> ------------------------------------------------------------------------------------------------------------------
> I think I may have solved this problem. One of the other posts mentions that
> the Z-bracket screws are too long and you don't get a tight fit. I changed
> the five screws from 5/16" to 3/16" and did notice a better grip between the
> bracket and the PA assembly. I have run it all evening and haven't heard a
> click or a pop. I even ran the temp up and still nothing. Will it last? I
> don't know, but it seems to have fixed it. The guy who suggested this has
> submitted it to Elecraft for a change. Good luck and lets hear if any of you
> have the same result.
>
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