[Elecraft] KPA500 thermal clicks

[Don Wilhelm]

Chuck and all,

The clicking/ticking sound is coming from the expansion/contraction of 
the "Z" bracket against its mounting screws.  Yes, it may seem to come 
from the heatsink, because the Z bracket is fastened to the heatsink and 
the sound will conduct to it.
The tightness of the screws may affect the amount of sound you hear.

Those wanting to reduce (or at least alter) the sound intensity may want 
to tighten the Z bracket mounting screws a bit after several hours of 
operation.  To tighten the screws into the heatsink (see page 22 of the 
KPA500 assembly manual), you may be able to open the cover of the KPA500 
and use a small angled #1 Phillips screwdriver, or you may have to 
remove the side panel and move the PA module assembly over.  The Z 
bracket to case mounting screws are accessible from the bottom (see 
assembly manual page 24), so try tightening those first.

73,
Don W3FPR

On 7/19/2018 9:18 AM, hawley, charles j jr wrote:
> The ticking sound is clearly the resonant aluminum heat sink fins. The mechanical shrinking or expanding is abrupt and resonates the fins much like a tuning fork.
> My take on it...