Thanks Francesco!
It takes several hours to do a proper cleaning of the geartrain to remove all
of the old grease. I have used WD-40 as a solvent and Krud Kutter as a
detergent since it seems that no one product can remove all of the grime. I
have found that old spray bottles are great for applying the cleaning liquids.
Rinse with water after each application, it will take several cycles to remove
years of crud. An acid brush on a wood dowel is used to go deep into the
geartrain. Finish with a final water rinse and then an alcohol rinse to
release the water. Now a thin wood skewer is used to deposit a small drop of
your favorite synthetic oil to each gear bearing which completes the process.
Do not lube the gears themselves. The less lube you use the better, it will
prevent dust and dirt from fouling the geartrain over the next 20 years!
You will be very surprised how easy it is to now turn the two frequency knobs,
I know I was. That "R-390 wrist" will be a thing of the past. Don't forget to
dab some synthetic oil on the guide rollers and bearings found on the slug
racks, they will need some lubrication too.
Regards,
Jim
Logic: Method used to arrive at the wrong conclusion, with confidence. Murphy
On Wednesday, October 8, 2025 at 01:59:57 AM CDT, Francesco Ledda
<[email protected]> wrote:
👍
Sent from my iPhone
On Oct 7, 2025, at 23:20, Jim Whartenby via R-390 <[email protected]> wrote:
For the life of me, I don't understand why people grease the R-390 geartrain.
The manual even says that it is better to not grease then to over grease. The
group that knows the most about gear works, in general, are the clock
collectors. Their advise is to sparingly oil pivot points and do nothing to
the gear teeth. It will only collect dust and gum up the works, if you do. As
for the R-390 or is it an R-390A? First, test all tubes, IRAN, second reseat
all connectors, then test again.
Regards,
Jim
Logic: Method used to arrive at the wrong conclusion, with confidence. Murphy
On Tuesday, October 7, 2025 at 03:56:50 PM CDT, Adam Morehouse
<[email protected]> wrote:
Hey guys,
I appreciate the pointers on my R-392, and now that it's buttoned up, it's
time to work on my R-390. I only tested this briefly when I first got it,
today I threw it up on the bench. Supposedly this was restored by Rick
Mish, it is very clean (except the gear train, which has a lot of fresh
grease...), and the front panel is pristine.
It does pull stations, but the volume is extremely low in AGC mode, and
gets slightly louder when placed into MGC.
In MGC, with the BFO switched on, it plays at a normal (not super loud, but
loud) volume.
In AGC, with the BFO switched on, it hums, low volume audio.
The limiter seems to have no effect, and varying the BFO doesn't do
anything at all no matter AGC/MGC.
I have Tom's solid state kit installed, and B+ at the AF deck test point is
a steady 180.5vdc.
I am going to dig out the TM's later on, I have them somewhere...but maybe
somebody here can help point me in the right direction.
Thanks!
Adam K2AAM
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