[TenTec] Hercules II fan noise

[Stuart Rohre]

Steve,
Definitely a noisey fan!   There is a resonance heard with something 
else.  Mounting the amplifier on a rubber pad may help.  Also, mounting 
a rubber gasket under the fan mounts may isolate it from the rig case.  
You have some noise there like dry or bad bearings.  If the thing is a 
muffin type fan, you can peal off the foil label and get to the 
bearing.  A teflon containing oil, like Triflow (TM) can revive a dry 
fan for a couple of years or more.  It is a spray on, oil product.  You 
may also have imbalance in the fan blades.  If you can borrow a 
Strobotach, (strobe light with variable flashing sequence related to 
RPM) you may be able to find out if it is the blades or a loose 
bearing.  If all else fails, a new fan probably is not all that 
expensive.  If you find out the flow rate of the old, you may be able to 
find a local equivalent.

GL and 73,
Stuart Rohre
K5KVH