[R-390] Cleaning R-390 gears in place before lube

[Charles Steinmetz]

Bob wrote:

>I've been down the road with this on a couple of radios. I'd *think* 
>I had everything sprayed out and clean. Eventually something would 
>get me moving and I'd tear down the gear train. There always was an 
>improvement after the tear down. Spraying stuff out of split gears - 
>very tough to do.

Most of the accumulated dirt and grime is just sitting there 
harmlessly.  Some of it gets between the teeth of meshing gears and 
slows things down, and a tiny bit gets into the bearings and between 
the split gears, but the rest is just ugly and does no harm.  UNTIL 
you start cleaning or lubricating it.

The "hose it down in situ" approach (with or without brushing) 
actually washes dirt INTO the bearings and between the split 
gears.  The only way to make sure there is no dirt in the bearings 
and between the split gears is to disassemble the gear train, clean 
everything down to bare metal, and put it together again, lubricating 
everything LIGHTLY as you go.  This also gives you a chance to 
inspect the gear teeth and the faces of the split gears for burrs or 
other defects and to remove them (carefully, with toothpicks, needle 
files, Xacto blades, small, hard cutting stones, and fine grit 
paper).  That is how one attains the ultimate smoothness of operation.

Best regards,

Charles