[Elecraft] KLPA3A power transistor thermal stress concerns

[Nick - VE3EY]

I have a K3s/10 (12 watt version) which I intend to use in the upcoming cq
ww cw contest.  This unit does not have KPA3A power brick and cooling fans
installed.

While doing some trial runs I noticed that the area around the KLPA3A power
transistors is getting fairly hot after prolonged contest use.  My guess is
the transistors are working harder when used as finals.  The rig needs to
produce between 6 and 12 watts to properly drive the SS amp I intend to
use.

Looking for some opinions:

1.  Don't worry about it.  I am paranoid.  The KLPA3A power transistors can
sustain the rigor of 40+ hours use in the contest.  Just make sure they are
properly fastened as directed in the assembly manual.

2.  Rig up some passive thermal cooling.   Perhaps a heat-sink underneath
the rig to allow heat to dissipate.

3.  Mount a 12v cooling fan somewhere to allow for airflow underneath the
radio to take away excess heat.



73

Nick VE3EY