[Elecraft] Burn in of KPA100

[Don Wilhelm]

Tom,

It takes both time and heat to seat the thermal pads.  Since yours has a 
good deal of time on it, but not a lot of heat, I would recommend that 
you tighten the screws now and then again after some period of operating 
at high power.  It is not that difficult to 'just do it'.

Do not 'beef' the screws down because there is danger of stripping the 
heat sink threads, but do apply a reasonable amount of torque.  It is 
really hard to describe what reasonable is, but consider that the heat 
sink is aluminum and the screws are plated steel.  If the screws appear 
to bind, remove them and put a small drop of oil on the threads and 
re-insert them.  In many instances of aluminum to steel contact, the 
aluminum can gall and make it seem as though the screw is tight when in 
fact it is not.  I have *not* experienced this with the KPA100 (perhaps 
the heat sink is a special alloy that does not have this effect), but I 
offer it as a guideline 'in general' where aluminum holes and steel 
screws are conceerned.

73,
Don W3FPR

NG3V wrote:
> Hello group,
>  
> I built the 100 watt amp last summer, but can't seem to overcome the urge to
> stay at qrp levels.
>  
> So, as I probably have only a few minutes of time at 100 watts, when should
> I reset the mounting screws.  Is this like 3 months or 3000 miles or is it
> strictly a matter of time?
>  
> Should I just pound out a few hours of tests into a dummy?
>   
>