[Drake] Fans: Starting to look like thermodynamics.

[WA2JJH at aol.com]

Bottom line is that many have placed the fan in l both modes (blow in/out)  
and many different places. However I have seen rear mounted and right over the  
final cage positions.
 
   The TX-4C is very well constructed. There is more copper(the  3erd or 4th 
best heat conductor) in the TX-4'S.(A,B,C). I have never heard of  anyone with 
properly working Drakes
to have such short tube life to be such an issue.
 
  Did anyone consider checking the Drake pages, or many of the other  
internet sources that have retired Drake engineers/Hams.
 
   I have a dual 3-500z amp. The fan is very large in diameter,  but very 
whimpy in terms air flow.
 
   This Amp is second hand. I do not know if the original factory  fan is 
inside. It is pulling air in through the back. The air is forced on  to the 
face'es of the Dual 3-500z's.
 
  I just got a bunch of brushlesss noiseless fans for cheap. Am I  going to 
add an extra fan to get a laminear flow on the tubes?!  How about  add fans to 
get maximum air velocity, period.
 
   I am certainly free to experiment. I have had the 3-500z's  running for 
about 3000 hours. I am not the original owner. The tubes are EIMACS,  so I know 
there are many more hours on those tubes than my  hi-swr  3000 filiment hours 
I put on them. All sorts of whacky loads.
Still get the same 1KW out on 20M. Just like the day I got it.
 
  My money is on the OM with the fans all across the top. Hi-Hi