[Elecraft] KXPA100 Thermal Fault

[Bert via Elecraft]

Thanks to all who made suggestions. I will be trying one or two fans atop  
the heat sink and see how that works out in the next RTTY contest foray.
While looking into possibilities, I checked out the web site where I got my 
 "add-on" KX3 heat sink (https://proaudioeng.com/products/) and found they 
had  added a new product, a power supply specifically for the KX3. Specs 
look  promising. [I don't have a vested interest in the company, just pleased 
with the  heat sink.]
Again, this reflector is a great source for ideas about great  products!
73, Bert N4CW/K1IMI
 
 
In a message dated 7/20/2014 7:18:48 P.M. Eastern Daylight Time,  
N4CW at aol.com writes:

I used my KX3/KXPA100 in the NAQP RTTY contest this weekend. The KX3 with  
added-on heat sink worked very well; however, the KXPA100 repeatedly faulted 
 with HI TEMPERATURE indicated on the KX3 at full output after prolonged  
operating (lots of CQ'ing with short pause intervals). PA.X temp indicated at 
 failure was around 60C...as it should. Shack temperature was around 70 
degrees  F
Yes, I know all about digital modes and full power stressing amplifiers,  
etc. What I want to know is how to mitigate this interruption yet run full  
output. To that end, I have a couple ideas: what if I mounted the amp  
vertically so the heatsink fins "drew" cooler air through themselves via  
convection? Secondly, would a couple muffin fans mounted atop the cooling fins  do 
the job? 
The net of this is that I'd like to enjoy the full benefit of having a  
high-quality 100-Watt amplifier, regardless of mode or key-down time.
 
Bert N4CW/K1IMI