[R-390] Green gear redux

Tue, 6 Aug 2002 10:01:00 -0400

Hi Scott:

My R-390-non-A was missing the coveted green gear, so I disregarded it
entirely as I went about the task of degreasing and degunking this grand old
radio. I didn't disassemble the geartrain. I soaked it, cleaned it, and
lubed it, but didn't
loosen or move any gears, clamps, or shafts after pulling the RF deck.

By the way, to get it back in sync after the big cleanup, first I set the RF
deck racks to the appropriate settings (rear cam line markings) as per the
TM photo, for what they should be at 02 000 (though the Veeder-Root counter
was not connected yet). I did that by manually turning the big split gear,
moving the cams around and around until they lined up. I visually checked to
see that the bandswitch contacts aligned properly by poking my beady eyes
under the chassis.

I then placed the RF deck on the chassis, loaded the brass split gear, and
dropped the assembly onto the gearset, with the counter set at 02 000. Then
I raised the right-hand front side of the RF chassis (as you face the set)
using the screwdriver technique described in the TM, not dis-engaging the
gears already set in the previous step, and turned the MEGACYCLE CHANGE
shaft a few turns clockwise. I then dropped the right-hand side onto the
loaded gear, and used the knob to turn the shaft and entire engaged gearset
down to the 0.5 MC band.

I then raised the chassis again, and turned the MEGACYCLE CHANGE shaft and
gear fully CCW again, and then placed the loaded gear in place, dropping the
chassis on the gears. Turning the shafts through the range of 00 to 31 and
the full 000 to 999 range on the VFO shaft (plus over-run) moves the cams
through their positions properly. The small subchassis moves up and down as
well.

The ol' 390 aligned beautifully. Dave Medley provided encouragement.

Vy 73, AI2Q, Alex in Kennebunk, Maine    .-.-.

-----Original Message-----
From: [email protected] [mailto:[email protected]]On
Behalf Of scott
Sent: Tuesday, August 06, 2002 7:30 AM
To: [email protected]
Subject: [R-390] RF rebuild

I have photos of every step of the dis-assembly and re-assembly of the
geartrain.
The pictures show the individual gear and the geartrain, and the next shot
shows
it installed with the next to go gear on the bench.  They are good quality
with a
white background.  If anyone wants these to annotate them, let me know and
I will send you a CD copy.

My first geartrain rebuild was a piece of cake.  I used Walter Wilsons
photos
as guides and had no problems.  Mechanical alignment and the RF bandswitch
alignment was also no problem, unlike I thought they may be.  The hardest
part
was hooking the damn springs up to the racks.  It operates very smoothly and
there
is no slop at all in the geartrain.  Oh, and it tunes only 500Khz to 32 Mhz.
I need something
more complicated now to keep me out of trouble....bring on a non-a.

Scott

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