[R-390] RE:R-390/URR

[Bob Young]

I'm sorry if I mislead everyone with my hurried description, it is not a 
clutch at all, (I found this out when I took it apart). The oldham coupler 
is fine, the PTO turns as it should (no play), the dial lock is not engaged 
and the zero adjust clutch is fine. The problem is in the kilocycle change 
control locking disc and split gears which is on the same shaft as the PTO 
but right behind the front panel. This disc turns the split gears which in 
turn drive the veeder router. The backlash as I called it is caused by a 
loose rivet that goes from the split gear to the disc, the disc turns the 
split gears through a riveted little shaft, this little shaft is riveted to 
the split gear and is loose whiuch is causing the play. It is shown on page 
72, #40 of the Field and Service Maintainance Manual for 390's, can also be 
seen on page 61 right in the middle of figure #37, but I have not been able 
to find an exploded view of it anywhere in the book. You can feel it when 
turning the kilocycle change knob back and forth, the PTO turns but the 
veeder router doesn't (just a little bit of back and forth play).  I took 
the panel off and pulled the part which consists of an approx 2 1/2" split 
gear and a disc, it is very hard to explain without the correct terms, but I 
need a new  kilocycle change control locking disc with split gears ( which 
is probably unobtanium.)

Bob
KB1OKL





>From: Flowertime01 at wmconnect.com
>To: r-390 at mailman.qth.net
>Subject: Re: [R-390] Oldham Coupler Maintenance
>Date: Mon, 29 Oct 2007 11:04:38 EDT
>Fellows,
>
>If you stretch the spring on the oldham coupler while spinning the KC knob
>and thus change the relation of the rotation angle between the KC knob and 
>cam
>shafts to the VFO position shaft then you have back lash.
>
>Too much friction causes the lash problem and maintenance fixes the lash
>problem.
>Sorry to make this look like a binding problem.
>
>Sorry the fix to a lash problem is cleaning and lubrication.
>
>Read Tim's tales of the stuff he has encountered.
>
>Backlash in gear trains is also a friction problem.
>It the gears have low friction then they are just sloppy and have play but
>not suffering from back lash.
>
>Roger.
>    </HTML>
>



>Bob,
>
>Do you by chance have the Dial Lock engaged?  As if you were going to 
>adjust the PTO to agree with the Veeder Root readout with the calibrator?
>
>Bob - N0DGN
>



>From: Joe Foley <redmenaced at yahoo.com>
>To: r-390 at mailman.qth.net
>Subject: Re: [R-390] Re: R-390/URR Date: Mon, 29 Oct 2007 17:55:32 -0700 
>(PDT)
>That would be the ZERO ADJUST clutch, the knob should
>be turned all the way counter-clockwise, but be
>careful, it may not be working correctly if not it may
>come apart.  Take a look at your working receiver and
>see how it is supposed to work.  Then verify that it
>does or doesn't.  If not, prepare to remove the front
>panel.
>
>You'll want to do some research on how to repair the
>clutch.
>
>Joe
>
>
>
>
>--- Bob Young <youngbob53 at msn.com> wrote:
>
> > I looked at it today and the PTO is turning fine and
> > there is no play there,
> > the problem is in the big front clutch gear (counter
> > drive gear?) right
> > behind the front panel. There is a little space
> > between the clutch and the
> > mating surface which is not in my other one. This
> > allows the PTO to turn
> > (had it opposite, sorry)  but the whole rest of the
> > mechanism doesn't turn,
> > you can feel it in the kilocycle knob, there is a
> > little play in it which is
> > why I called it backlash. I have loosened the clamp
> > and moved the large gear
> > to see if the gears were worn but this had no
> > effect. I would say there is
> > about 1Kc of play there in which the PTO turns but
> > the readout doesn't, I
> > judges this by the BFO.
>