[TenTec] Argonaut 509 - PTO rebuild parts/instructions needed - still possible? advice/recommendations?

Ed - K9EW k9ew57 at gmail.com
Sat Nov 21 17:08:16 EST 2020

The Mobil 1 synthetic grease is what I use too.  Guess we both have more
than a lifetime supply!

enjoy the '509.  I still have mine, but haven't used it in a while.  It's
getting to be boatanchor weather, so will be going to high voltage and
vacuum tubes.

72/73 - ed, k9ew

On Sat, Nov 21, 2020 at 1:56 PM <wb0gaz at yahoo.com> wrote:

> Hi Ed,
> I got up to reassembly step 19 (bearings in place) and discovered that the
> vfo shaft was not transmitting enough torque to the core drive rod (not
> transmitting any torque counter-clockwise, so no return to the CW portion
> of the band!) so I backed out to step 16 (removing the core drive rod and
> stuff), cleaned all of the removed parts of grease, and reconsidering the
> type of grease for the vfo/bearing/core drive/race interface - the Mobile 1
> grease (hand on hand) I used might be too slippery for that application.
> This (torque transmission) was the original problem I ran into, but now
> (after cleaning and re-greasing the pistol thread and the threads on the
> core drive rod), the core drive rod turns fine by hand. Another reply
> suggested Lucas Red "N" Tacky #2 for grease, so I'm going to include that
> with my next order for "stuff" and use that for the affected area.
> The reference to super glue is at step 14 ("Apply a small quantity of
> super glue on each side of the retainer"); this was the location where glue
> was found and mentioned in step 9 ("These parts are sometimes glued in
> place and all old glue must be moved..." - that was the case for this
> radio.) The glue is just to keep the retainer stuck to the case, and not
> for the bearings/race interface (that is handled by the viscosity of the
> grease and pressure between the vfo knob, race and bearings.) After
> removing the retainer while backing out (so I could re-clean the race and
> remove the Mobile 1 synthetic grease there), I decided there is sufficient
> friction fit for the retainer (vs. the housing) that adhesive is not
> necessary, so I'll skip that on the next reassembly.
> I did a century 21 PTO rebuild some years ago (when the kit was available
> from ten-tec); I don't recall having any difficulty with it, but I did use
> their supplied (green) grease, and also I didn't have the problem then that
> I did with this radio, where the VFO shaft initially was not transmitting
> sufficient torque to move the VFO at all, so that's what stymied me in
> trying to get past step 4 this time around.
> Anyway, thanks for the reply and I'm grateful for any advice as I continue
> this adventure!
> 73 Dave WB0GAZ wb0gaz at yahoo.com
> On Saturday, November 21, 2020, 12:36:56 PM MST, Ed - K9EW <
> k9ew57 at gmail.com> wrote:
> Hi Dave,
> It sounds like you're making progress, but I've never seen 'super-glue' or
> '2-part epoxy' mentioned in a PTO rebuild.  Are you sure you need that?
> The inner shaft is supposed to make the ball bearings rotate, which in turn
> makes the outer shaft rotate.  If you need something to hold those ball
> bearings in place, a dab of lubricant is usually sufficient.
> There's a wide range of suggestions for which lubricant to use.  I've used
> white lithium grease (eventually dries out), synthetic bearing grease (a
> little bit too viscous for my taste), and - most recently - triflow bicycle
> lubricant (still going after 2 years).
> Too bad those PTO's don't have a grease fitting like cars do (or did).
> 73,
> ed - k9ew
> On Sat, Nov 21, 2020 at 12:04 PM wb0gaz via TenTec <tentec at contesting.com>
> wrote:
>  Thanks, Bob - my initial search on groups.io didn't use the correct
> search term - I'll wander over there shortly!
> Progress - the problem step (#4) was that ten-tec directed that the PTO
> setting be fully clockwise before starting work, which would normally push
> the limit pin close to the back end of the assembly (so pushing in a bit
> more would expose it to remove the pin). In my case, the (small inner) knob
> shaft transmits no torque to the (larger outer) core drive shaft so this
> step (which is critical) wasn't done properly.
> Finally figured out that the core drive shaft would need to be turned
> manually a few turns (clockwise) to get the limit pin accessible. Although
> it was pretty stiff, the core drive shaft did turn three turns, and let me
> resume work. I've since done the degreasing and started assembly (using
> tiny dabs of 2-part epoxy rather than superglue to reattach the bearing
> race component to the housing, as it seems superglue would make a future
> repair job harder.
> So, thanks for the replies!
> Dave
>      On Friday, November 20, 2020, 11:11:38 PM MST, <wb0gaz at yahoo.com>
> wrote:
>   Found that I had the ten-tec instructions in my file, so proceeded up to
> a point where I am stuck, so looking for advice:
> PTO subassembly housing (that holds the coil and movable parts) removed
> from the 509 Argonaut without difficulty; all of the various small parts
> are stashed in small plastic bags.
> (referring to the ten-tec instructions on PTO rebuild)
> "Step 4. Push tuning shaft (J) back far enough to remove stop pin (H)
> using long nose pliers. Note the position of this pin as it must be put
> back in the same hole."
> I am not able to push the tuning shaft (J) back (I presume by back, they
> mean push on it towards the rear of the radio) very far at all - certainly
> not enough to expose the stop pin so I can safely remove it (I assume the
> idea is to push the shaft back towards the rear until the stop pin is clear
> of housing so that the stop pin can be removed.)
> The small-diameter inner shaft (where the PTO knob is attached) turns
> normally, but no movement is transmitted to the gear-reduced
> larger-diameter outer shaft (where the kHz ring and string wind-up goes),
> which I think is what actuates the PTO movement forward and backward for
> frequency change.
> As far as I can tell, the root problem is that the "core drive rod (K)" -
> which is the larger-diameter shaft just behind where the PTO knob is
> attached - does not turn at all (certainly not by hand, and I've not tried
> using any tool to turn it because it seems very unwilling to rotate.)
> Turning this is necessary at step 7 so it can be removed from the assembly
> housing. I can't work out why it does not turn. What grease I've cleaned up
> so far seems normal consistency.
> I can press the tuning shaft (J) in maybe 1/8", and I see the three ball
> bearings move back in their plastic housing, but they're not exposed enough
> to remove them.
> Does this ring a bell with anyone? I'm stumped!
> Thanks,
> 73 Dave WB0GAZ wb0gaz at yahoo.com
>      On Friday, November 20, 2020, 08:06:37 PM MST, <wb0gaz at yahoo.com>
> wrote:
>   My Argonaut 509 (S/N 509-3xxx) has been in storage for a long time, and
> after unpacking it and putting it in line, I discovered the PTO (frequency
> dial, not the resonator rack) control is largely immobile. I suspect the
> PTO mechanism grease has gone bad and I'd need to remove the PTO,
> disassemble, remove the old grease, apply new grease, reassemble,
> re-install and realign.
> All that said, the last time I did this (for another PTO-based analog
> Ten-Tec transceiver) was some years ago and Ten-Tec at the time could
> supply the needed materials and instructions.
> I presume with Ten-Tec gone that I'm "on my own", so looking here for any
> advice as to how to proceed. I no longer have the materials (I recall a
> kind of green grease and a very small metal part) nor instructions (a few
> photocopied pages, which served well the last time I did this years ago.)
> The 509 seems otherwise to be in good shape, it's just stuck at xx.060 MHz
> or thereabouts.
> Thanks for any suggestions!
> 73 Dave WB0GAZ wb0gaz at yahoo.com
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