[R-390] The R-390 Cookbook by A.J. Carmody: Beware!

[ToddRoberts2001 at aol.com]

In a message dated 9/14/2006 12:19:40 PM Eastern Standard Time, 
roy.morgan at nist.gov writes:
One of the mods he suggests replaces the two 6082 24 volt series regulator 
tubes with two of the more common and cheap 6080 6 volt ones. His method 
puts the two tube filaments in series with a diode to rectify the available 
filament supply to half wave.

THIS IS A BOGUS DESIGN.  DO NOT DO IT.

Thanks for the reminder of a destructive mod for the R-390! Nothing more 
aggravating than to bring home an R-390 and find it has had unapproved hidden mods 
done to it, usually with bad results and no schematic or paperwork to back it 
up. I have seen several that were butchered by removing the antenna relay and 
an SO-239 installed usually with blobs of solder hanging off  the wires and a 
couple of holes drilled off-center. But even these travesties can be 
corrected with some TLC!  And who can forget seeing an R-390 with the ballast tube 
missing and usually 2 or 3 big  resistors in series with their leads twisted 
together hanging out in the open just waiting to short against something and 
jammed into the 9 pin socket? 73 Todd WD4NGG