[R-390] VFO end point off 17 KHz

[Larry H]

Dave, Since 27 mh is for the cb band, do you care how close in frequency it
is?  I have 1 that is 800 h low I will sell you for $8 + shipping.

Regards, Larry

On Sat, Nov 2, 2019 at 6:48 AM David Olean <k1whs at metrocast.net> wrote:

> Hello Mr. Bottled Water, (Perrier)
>
> OK on all the advice. It sure does sound like there is something wrong,
> but with ferrites that are 50+ years old, you can get some significant
> drift too. I have an old 144 MHz Tecraft xmtr from my boyhood that had
> all the slugs drift so far down that it stopped working. I had to modify
> all of the multiplier coils to get it back on 24 and 72 MHz.  That is a
> pretty drastic change.  That is what prompted me to diddle with the end
> point coil. So now it is working great with nice linearity across 950
> kHz and only 500 Hz off at one end.  I'll come back to this problem
> soon.  Getting the PTO out is sorta simple, so I will order some new
> capacitor parts and come back to it on some cold winter night. In the
> mean time, I am re aligning the entire set and fixing a few problems.
> The carrier meter has stopped working and the RF gain control is acting
> funny. This R-390A had the antenna relay removed and an (ugh) SO-239
> connector installed in its' place. I just bought a relay and am looking
> for the wires to re install it, but can't find them ?  I am not sure,
> but think they must have been clipped and removed. I'll run new wires to
> the rectifier and get it all working.
>
> I also found that the 15.000 MHz crystal has died.  This only affects
> the 27 MHz band.  It will not oscillate, or if it does, it is very weak.
> I need a replacement crystal. I found a 7.500 MHz one in my junque box
> and it actually works, but output is a bit low and injection is not
> enough.  Fair Radio does not list any. I am looking for a replacement.
>
> If anyone has a Cosmos PTO I would be interested in getting another one
> to work with as well.  They do get addicting.
>
> 73 Dave K1WHS
>
>
> On 11/2/2019 5:42 AM, Perry Sandeen via R-390 wrote:
> > Yo Bubba Dudes!,
> > I agree about returning the end point coil to its original 3 turns.  I
> disagree with fixing the drift with adding caps.
> > With that amount of drift there is something wrong with one or more of
> the OEM caps. As you said they're 50 plus years old. IMNSHO, you should
> shotgun the caps a well as the resistors using 1% MF replacements. Even in
> small quantities there about 25 cents each from Mouser with no minimum
> order.
> >
> >   Members are reporting that tiny silver migration is causing havoc with
> old SM caps that test OK.
> >    Dan's Small Parts carries a nice selection stating at 1pF so you can
> get just what you need with series and/or parallel combinations. You'll
> probably still need a N200 cap as well. Fixing PTO's is as much art as
> science with patience being your best tool.
> > Regards,
> > Perrier
> >
> >
> >
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