[Elecraft] KPA500 Heat Expansion Pop

[Don Wilhelm]

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.
>