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@yahoo.com
On Saturday, November 21, 2020, 12:36:56 PM MST, Ed - K9EW
<k9ew57@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@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@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@yahoo.com
On Friday, November 20, 2020, 08:06:37 PM MST, <wb0gaz@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@yahoo.com
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