[R-390] Dumb Mechanical Alignment question

Thu Jul 16 16:48:25 EDT 2026

Paul-
That wrapping a coil around the osc tubes is one way and works, also you 
can check directly both 1st and 2nd , the 1st which directly accessed at 
(IIRC for r390) J421/P221 and the 2nd is J422/P222, if you are having 
freq adj issues in the osc deck the caps are also switched independently 
of crystals so another potential spot and that is internal osc deck 
alignment and is pretty good and generally not an issue however....
there is also test spots at the grid of each mixer ( IIRC) E209 and 
E210......I need go look a the manual it has been a while for both 390 
and 390A.
i know there is also a spot on the 1st mixer grid for the input signal 
E20? after the RF front end.
remember at the grid of the mixer you are looking backwards to previous 
stage, injection is on the cathode. do look a the schematics to make sure
i gave correct locations
HTH
Renée

On 7/16/26 11:58 AM, Paul Roche wrote:
> Renee, I think you are right. Unfortunately I can’t seee that now. How 
> do I check that the Osc is working on each band, listen 455kc up from 
> each MHz position with a coil around Osc tube?
>
> Playing just now with sig generator input, took about 1 VOLT output to 
> hear signal at 2900 or 3900 kc!! That’s pretty deaf. I need to check 
> tubes, it worked pretty well 2 weeks ago; sounds mechanical to me.
> Sent from my iPhone
>
>> On Jul 16, 2026, at 2:45 PM, Renee K6FSB <k6fsb.1 at gmail.com> wrote:
>>
>>  There is a possibility that the osc contacts are not quite in sync 
>> for ALL bands. in other words poor contact or slightly off the contacts.
>> you may have to massage / move slightly to have good contact over all 
>> positions, the orientation of that gear may need to be shifted...it 
>> does not take much. check that the osc works in all positions before 
>> doing anything.
>> Renée
>>
>> On 7/16/26 11:13 AM, Fred Moore via R-390 wrote:
>>> Paul,
>>>
>>> Thanks for bringing up this thread.  I have exactly that problem with an RF
>>> unit here.  I rock the MHz knob.  Signal gets a lot better.  To me, that looks
>>> first like the basic mechanical alignment.  If someone hasn't messed with the
>>> electrical alignment, everything might fall into place.  Then check
>>> sensitivity on each MHz to confirm the electrical part.
>>>
>>> On the R-390 the painted lines are to the rear and may require the removal of
>>> the osc unit to see them.  On the R-390A the lines are on the front of the RF
>>> unit (if no one accidentally cleaned them off).
>>>
>>> -Fred
>>>
>>> ------ Original Message ------
>>> Received: Thu, 16 Jul 2026 06:01:55 PM GMT
>>> From: Jordan Arndt 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
>>>
>>> Paul...
>>>
>>> Which version of the manual are you using...?
>>>
>>> I'd check the synchronization of the gear train and verify that the
>>> positions of the cams is correct according to the manual...
>>>
>>> 73...Jordan VE6ZT
>>>
>>>
>>> ----- Original Message -----
>>> From: "Paul Roche via R-390"<r-390 at mailman.qth.net>
>>> To: "R-390 Mailing List"<r-390 at mailman.qth.net>
>>> Sent: Thursday, July 16, 2026 10:59 AM
>>> Subject: 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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