[Elecraft] How hot is too hot

[kc4kgu@ENTERZONE.NET]

On Tue, 5 Nov 2002 K9OZ@aol.com wrote:

> I got the KPA100 running with only minor troubleshooting, and it seems to be 
> running like a champ. Gave it a good workout in SS last weekend. But can't 
> find anything on how hot is too hot on the heat sink.
> 
> If I wait for fan to come on (whether set on normal or low/high) it seems 
> like the sink gets pretty warm to the touch before the fan kicks in. The fan 
> seems to cool it, hold down heat well. So for the contest I just switched it 
> to High fan and let it run.
> 
> But tonight in a casual QSO, top was hot again before fan kicked in. Is this 
> normal, or should I be checking things twice?
> 
> Bruce, K9OZ,


Bruce,

When I did the KAT100 field test, the CAL tPA is one of the settings that
I neglected to note.  Since my thermostat is on the main floor of the
house and my shack is in the basement, I didn't have any true reference to
what the temp in the shack really was.

To err on the SAFE side, here's what I did:

I operated the rig into a dummy load until the top cover felt "warm to the
touch" and then adjusted CAL tPA to the point that the fan kicked on.

It's not very scientific but, the fan kicks in when the heatsink gets warm
now.

I'm sure someone else will provide a much more scientific method but, that
has worked for me.

73 de John - KC4KGU
K2/100 #2490