[Elecraft] KPA100 Issue

[David Robertson]

To All,

Though there is some mention about tightening the screws that mount the final power transistors in the manual, it can be easily missed.

When I first built the KPA100 I made sure the transistor hear sink mounting screws were tight.  After operating the rig for about a week (and heat cycling the heat sink) I had an opportunity to open up the K2 to show a friend. At that time something in my mind reminded me to recheck the final transistor heat sink mounting screws (please remember the screws were carefully tightened upon assembly) and to my surprise I could easily tighten the screws 1/2 turn or more! It seems the heat conducting material cold flows a bit between the final transistors and the heat sink.
So for those who have a KPA100 it would be prudent to check those final transistor heat sink mounting screws every so often. If you don't you could lose your finals.

73

Dave KD1NA