[R-390] Dumb Mechanical Alignment question

[Fred Moore]

Oops!  I spoke to soon.  I am with Jacques on this! 

Early 1970s.  I'm in high school.  A serviceman who came back from Vietnam was
the AV tech there.  He was telling me that he would occasionally get in an
R-392 which stopped working.  A user had turned every screw inside to try to
get it to work.  Not good.  He knew what he had to do next.  That was sage
advice to me, still a kid, to apply thoughtfulness instead of random action
when encountering a problem.  

-Fred 

------ Original Message ------
Received: Thu, 16 Jul 2026 06:06:29 PM GMT
From: Jacques Fortin via R-390 <r-390 at mailman.qth.net>
To: "'Paul Roche'" <rochep at comcast.net>,	"'R-390 Mailing List'"
<r-390 at mailman.qth.net>
Subject: Re: [R-390] Dumb Mechanical Alignment question

STOP STOP !
This is the proof that the electrical alignment is OFF !
When you move the MHz off the detent, that moves the cams too !
Does the MECHANICAL alignment is full OK at 07+000 ???
All the cams alignment lines at the center of the cams holes ???

IF YES, all you have to do is the electrical alignment now !
Do not move anything of what you take so long to synchronise on the mechanical
side !

73, Jacques, VE2JFE in Montreal

-----Message d'origine-----
De : r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> De la part
de Paul Roche via R-390
Envoyé : 16 juillet 2026 13:00
À : R-390 Mailing List <r-390 at mailman.qth.net>
Objet : Re: [R-390] Dumb Mechanical Alignment question

Aw nuts, mechanical alignment! As I wiggle the MHZ shaft off the detent the
station I am listening to gets MUCH louder!! I thought I was careful about the
detent at 7.000+ had the RF bandswitch on Geneva/giant bandswitch for each MHz
dead on; I guess not. Off she comes again. 
Sent from my iPhone

> On Jul 16, 2026, at 12:05 PM, Jacques Fortin via R-390
<r-390 at mailman.qth.net> wrote:
> 
> Paul, Barry:
> It's the alignment...
> Paul cannot know if it was properly aligned before.
> IF the position of the cams is dead-on correct at 07+000 NOW, it is possible
that it was "off" before.
> The RF deck alignment is a long and tedious process, but it cannot give
proper results if the mechanical part is/was "off", even slightly.
> The global "play" around the theorical center adjustment frequency (when it
is properly adjusted) is not more than about 50kHz wide, so it is easy to be
"off adjustment" on any band.
> If the BCB band works OK, it is already good: the 17MHz oscillator is
working !
> But even with the global tuning completely "off", it is really hard to not
receive a 50kW AM station...
> 
> 73, Jacques, VE2JFE in Montreal
> 
> -----Message d'origine-----
> De : r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> De 
> la part de Barry via R-390 Envoyé : 16 juillet 2026 11:23 À : Barry 
> <n4buq at knology.net> Cc : R-390 Mailing List <r-390 at mailman.qth.net> 
> Objet : Re: [R-390] Dumb Mechanical Alignment question
> 
> It occurred to me that it's apparenty working on TWO bands.  It could still
be the oscillators.  Can you hear the calibrator on any of the other bands?
> 
> Barry - N4BUQ
> 
>> Very good!  If it's working on one band (BCB), then it likely is not 
>> the PTO.  I think I'd tend to check the crystal oscillator(s).
>> 
>> 73,
>> Barry - N4BUQ
>> 
>>> Got her all back together. The good news is it picks up my super 
>>> loud local AM stations about where they should be on the dial! The 
>>> bad news is that’s basically the  ONLY stations it gets!!! Seems to have
lost all sensitivity.
>>> I’ll work on it; I doubt it’s the RF deck since stations come in at
>>> 950 and
>>> 1260 and 1500 kc as they “should”. Will check PTO and tubes.
>>> Sent from my iPhone
>>> 
>>>> On Jul 16, 2026, at 7:27 AM, Paul Roche <rochep at comcast.net> wrote:
>>>> 
>>>> Thanks so much, I might get it back together today and will give it a
shot!
>>>> Sent from my iPhone
>>>> 
>>>>> On Jul 15, 2026, at 10:50 PM, Jacques Fortin <jacques.f at videotron.ca>
wrote:
>>>>> 
>>>>> Hi Paul,
>>>>> 
>>>>> When the counters are at 07+000 the PTO output have to be at 2.455 Mhz.
>>>>> The PTO output change "in reverse" relating to the tuned frequency:
>>>>> if the shaft is turned clockwise, the outpu

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