[R-390] Cleaning Gears & Cams

[tfrobase]

Several years ago, while living in eastern Pennsylvania, I found an
industrial ultrasonic cleaner at one of my favorite scrap yards.  It has
become invaluable in the restoration of r-390a's.  

I have been fully immersing the detached gear assembly and the inductor
racks, with the inductors removed.  I use a solution of water based
degreaser in fairly high concentration.  It takes about 3 - 5 minutes to
complete the job.  After the ultrasonic cleaning I thoroughly rinse the
assembly in hot water and dry.  I then apply heavy oil lubrication with a
hypodermic.  My experience has been excellent, tuning has been smooth as
silk ... Tom, N3LLL

Take a look http://www.kitparts.com/misc/390-gears.jpg

Thomas L. Frobase, N3LLL