The AM Forum

Does anyone have an idea how to fix a worn bushing on the inside of the PTO? Its the one attached to the ferrite core. The threaded bushing is worn so you get side slop.  This is causing the frequency to jiggle around when tuning making it unusable for CW and still a bit annoying on AM. Its so bad that when you disassemble the PTO you can feel the slop on the bushing when you move it side to side. This is the RX tied to my 75m TX and I want to get back on 75 AM without moving a lot of stuff around!!!!!

  yo'


      you may want to try leaving the front panel
bushing loose, (or loosen it now) and let the shaft
center up on the pto. then tighten the front panel
bushing. Common problem.

"The threaded bushing is worn so you get side slop."

       should not be an issue when "Installed" in
the rig... The "Oldham Coupler" should be dealing
with that unless the "Kilocycle Change" knob is
really off centerline with the PTO shaft.

        Same with the "Megacycle Change" knob...
When I reinstall a 390/390A front panel, the second
to last step is tighten those bushings. the last
step is to put the knobs back on...

      Having the rig sitting on the bench with
front panel up helps..  You could also try swithing
the MC Change bushing with the KC change one.

       Good luck with that, but "Mechanical"
instability is NOT an issue with "R-39*" series.


       Please keep us in the "loop" on this.

73

/Dan

Try to look in Fair Radio's web site. You might be able to find another one that isn't worn out, like yours. Doing anything in there is a real challenge. It was built like a clock and pretty complicated.

Here's a link to Fair Radio.

https://fairradio.com/?s=r390a

There is a "VFO" for sale. VFO should be the same as PTO. Looks like $32.00

Several for SALE on eBay

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2060353.m570.l2632.R2.TR6.TRC2.A0.H0.Xr390a.TRS0&_nkw=r-390a&_sacat=1500

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Fred