[R-390] R-390] PTO identification

[bernie nicholson]

----- Original Message ----- 
From: "bernie nicholson" <vk2abn at bigpond.net.au>
To: "Gary Gitzen" <garyg at uwave.com>
Sent: Thursday, January 05, 2006 8:56 AM
Subject: Re: [R-390] PTO identification


> Ok Gary the progesteron PTO transfers are particularly delicate and come
off
> very easily , the Cosmos can be identified by its having an extra hole in
> the front , if you don't have a cosmos the other VFO s are very similar ,
> the first thing to do is the Endstop adjustment which just takes a few
> minutesyou need to establish that you are getting 1Mhz coverage in 10
turns
> exactly , if you cant achieve this you may have to remove a turn from the
> coil , its not as hard as it sounds but you do have to remove the covers
and
> the oven assy. and unsolder a few wires , whilst inside you can check
> resistor values ect, it then needs to be reassembled powered up and the
end
> point set again ,THEN you need to check the linearity, START at either end
> 1Mhz and check the 100khz CAL points they should be close, if not you need
> to Draw a graph of the response across the 1MHz band to see where you are"
> out "  I use the dial of a 10 turn Pot.  for this and do it outside the
set
> but with the VFO connected to the 390, when you take it apart you would
have
> seen the Corrector stack assembly , you need to look at the graph and see
> where its out sometimes its only necessary to alter 1 or 2 of the cams ,
> when you put the covers back on things change a bit , you will need to set
> the end point again each time , Some times I have had to pullthem apart
and
> repeat the process 15 times and I can tell you that it would try the
> patience of a Jesus let alone a normal person , , But incrementally you
see
> you are making progress , the linearity is stays put in my experience for
at
> least another 15 years , the cosmos is easily adjusted and doesn't even
need
> to be removed from the set ,You just drop the front panel down ,The Guys
who
> designed the Cosmos new a lot about VFO s they  introduced a  transceiver
> that predated the Collins Called the COSMAPHONE , you will see adds in QST
> around 1956
> ----- Original Message ----- 
> From: "Gary Gitzen" <garyg at uwave.com>
> To: <vk2abn at bigpond.net.au>
> Cc: <garyg at mail.uwave.com>
> Sent: Thursday, January 05, 2006 5:12 AM
> Subject: Re: [R-390] PTO identification
>
>
> > Hi Bernie,
> >
> > Your recent submission to the R-390A list implied you had calibrated
> > both styles of PTOs used in the 390A.
> > I recently picked up another 390A which needs a full realignment,
> > so will need to do that one. I also have a known functioning PTO
> > in my EAC 390A which is known to be off by a few KC, and I'd like to
> > make it right. I also have a depot packed spare I've never plugged
> > in, and if I start calibration PTOs I might as well check
> > that one too.
> >
> > I've heard that the Cosmos is "easy" to do, while the other
> > (Progrestron?) style is very difficult. This appears to match
> > your experience.
> >
> > Now for my question: how can I quickly identify which types
> > I have, ideally while it's still inside the 390A? The labels,
> > of course, have long ago disintegrated. Sigh.
> >
> > Thanks for any help.
> >
> > Regards,
> > Gary
> >
> >
> >
> > -- 
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>