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On 2023-11-23 17:07, Steve Wedge, W1ES/4 via groups.io wrote:

Slipping tuning usually, in the C Line, is due to a hardened bushing
on the main shaft. Today, that will mean cutting some high pressure
fuel line to precise dimensions to couple the knob to the skirt.

*** I think that's happening on my TR7. The bushing is hard as a rock.
I didn't know it was supposed to be soft :). With a working digital
display, it's not THAT big a deal, but still...

Sounds like an easy little project.

- Jerry, KF6VB

Most times, slippage of tuning
Is due to the slippage of that bushing.

73,

Steve Wedge, W1ES/4

Time flies like an arrow. Fruit flies like a banana.

Sent from Proton Mail [1] for iOS

On Thu, Nov 23, 2023 at 18:18, VE7PS <ve7ps@...> wrote:

Gordon:

By all means yes! Many of my Drakes have had exactly this level of
cleaning, though many have had the full removal and disassembly too,
which is always better. That said, the most common problem in the
C-line is gumming up of the ball race at the front of the PTO.

Acetone would likely work as well....but I like to use the 99%
alcohol and have stuck with that for years. It's easier to breathe
than acetone! Easier on the hands too.

In order to avoid removal and disassembly, I douod do the following;

1) Remove the tuning knob and sponge rubber bushing on the front.
Remove the top cabinet cover, the dial light shroud and blue/white
plastic lenses. Set the dial pilot lamp off to the side. Don't lose
the 3 screws/locks and spacers!

2) Put a thick soft cloth down and position the radio FACE DOWN. You
may have to get inventive to do this - just be careful of the front
panel.

3) Using your chive of solvent and some 6" swabs if you have them,
swab out as much of the grease in the bearing race as you can. You
should be able to get rid of almost all of it. Some fluid may leak
down the front of the PTO shaft and out the front. This will take 6
or 8 swabs to do this, at least.

4) Swab off the threaded tuning rod in the PTO, as well as the "one
sided tuning fork" and shaft that it rides along.

5) Swipe your bottle of sewing machine oil from your spouse. Drop
ONE drop on the threaded rod and run the PTO end to end a few times.
Swab off any excess oil, but do not wipe the threaded shaft clean of
the new oil. Using a small stick like a piece of a 6" swab stick,
drop in a gob or two of grease. I have used white lithium but have
switched to copper-infused grease of late and it seems to work well.
Clean up any excess grease leaving only what's in the bearing race.

6) Turn the radio so the front panel is upright. Drop ONE DROP of
the sewing machine oil on the 1/4" steel tuning shaft where it runs
into the brass bushing. Wipe off any excess. Work that in by tuning
the PTO back and forth. Replace the sponge bushing, dial skirt and
knob. Press in on the knob, then tighten it.

I just did this with an RR-2....sort of an SPR-4 with built in FS-4
synthesizer, and it worked well. The gears were all clean to start
with but removing the front panel on htis radio is much more
involved than an SPR-4 and I did not want to get into that.

Good luck! Let me know how it goes.

73
Peter
VE7PS

6

On Thu, Nov 23, 2023 at 2:25?PM Gordon, KJ6IKT <gfsmith@...>
wrote:
Hi Peter,
I had a question for you. I know this is a semi old thread, but ran
into this exact PTO issue on my SPR-4. The PTO bearing area is
slipping/gumming up and I believe it needs to be cleaned. Would you
see any issue with using acetone vs. the 99% alcohol to clean the
balls/ball race with the PTO still installed? The rest of the PTO
gears look pristine and I wanted to try the "in place" cleaning
before I go to the PTO removal and clean process.

73, Gordon KJ6IKT

On Sun, Jul 16, 2023 at 03:38 PM, VE7PS wrote:

Steve:

I agree 100% with your theory on migration of the lighter components
of the bearing grease.

I have been using white lithium grease on the ball race for years.
I've never had to go back and re-clean one, and re-grease, though
there are so many Drakes here none of them get "over-used".

Removing the front panel just makes so much sense and allows proper
cleaning of the Preselector tuning drive, all the pots, etc. I can
have the front panel removed and the PTO out in 10 minutes or less.
Great time to clean and re-whiten the line on the knobs too! Front
panel gets cleaned then a couple of coats of Pledge with a soft
cloth polish between the 2 coats and again after the 2nd coat. I
wouldn't even dream of cleaning a PTO gearset without removing it
from the rig.

That said....you CAN do a pretty good job of cleaning the front PTO
bearing without removing the PTO. You do need to remove the lamp
hood and dial light socket. I use 6" cotton swabs dipped in 99%
alcohol and clean the bearing as best you can. Rotate the dial
during this process. You will need 6 or 7 swabs in all likelihood to
eliminate most of the old grease. Use the whole lithium sparingly.
One or two VERY small dabs will be enough. Use the stick end of the
cotton swabs you just used to clean the bearing out.

73
Peter
VE7PS

Links:
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[1]
[2] /g/DRAKE-RADIO/message/74690
[3] /mt/100184156/243852
[4] /g/DRAKE-RADIO/post
[5] /g/DRAKE-RADIO/editsub/243852
[6]
/g/DRAKE-RADIO/leave/12260778/243852/767576506/xyzzy