[R-390] Alternative to IERC tube shields?

[Roy Morgan]

On Aug 17, 2009, at 11:07 AM, Robert Nickels wrote:
> ... while I haven't done any testing to prove it, I would
> think that adding a bit of forced convection cooling would help a lot.
> Thanks to cheap and quiet brushless muffin-type fans it is easy to try
> at least.

It's so.

I was working on an R-390/URR with the two 6082 series regulator  
tubes. I'd lashed up an external 6.3 volt filament supply and  
substituted 6080's for the 12 volt 6082's and fed them with common  
thick speaker wire.  The tubes melted the plastic insulation on the  
wires.  So I made a fan plate to hold a 4 inch muffin fan against the  
side of the radio, using existing screws for the frame and bottom  
cover.  With the fan running, I can hold my fingers on the tubes and  
not get burned.  The fan cools at least the whole bottom of the radio,  
and likely some of the top too.

I have a picture of the thing with a ruler included so you can make  
one for yourself if you like.

Roy Morgan
k1lky at earthlink.net
529 Cobb St.
Groton NY, 13073
Home: 607-898-3607
Cell: 301-928-7794