[R-390] Removing Megacycle Change shaft

[rochep at comcast.net]

A quick question for gear re-assemblers. For the MHZ gear (on MHZ shaft) Chapter 10 of manual says the clamp faces IN when assembling (page 10-15) but another section of Chapter 10 shows the clamp facing OUT. Chapter 6.3.19 also says the MHZ gear clamp faces OUT.

I ask because when the clamp is facing IN I am unable to merge the gear with the INNER gear of that big “differential assembly” (which uses the detent spring).  Regardless of clamp in or clamp out, does the MHZ gear merge with the OUTERMOST gear of that differential assembly (as does that small gear just above the MHZ gear) or does the MHz gear merge with the INNER gear of the differential assembly? It looks to be inner from the pictures, but hard to tell for sure.

Paul

From: r-390-bounces at mailman.qth.net <r-390-bounces at mailman.qth.net> on behalf of Fred Moore via R-390 <r-390 at mailman.qth.net>
Date: Monday, June 29, 2026 at 12:02 PM
To: r-390 at mailman.qth.net <r-390 at mailman.qth.net>
Subject: Re: [R-390] Removing Megacycle Change shaft

Hi Barry,

Congratulations!  I've been reading the mail, because I have an R-390 gear
train which had been partly disassembled and is no longer synchronized.  I am
setting that one aside for now.  But you have inspired me to tackle it later.


-Fred

------ Original Message ------
Received: Mon, 29 Jun 2026 02:36:45 PM GMT
From: rochep--- via R-390 <r-390 at mailman.qth.net>
To: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net>
Subject: Re: [R-390] Removing Megacycle Change shaft

Just a quick follow-up: I have all gears back together and motion is OK. I
have a couple of gear clamps “tight” but still the cams don’t move along
with the gear. I have new clamps on the way so when I break one…  Learning
alot; those split gears are a pain to install. Getting there. I really wish I
didn’t take it all apart, but what’s done is done.

From: Barry <n4buq at knology.net>
Date: Tuesday, June 23, 2026 at 11:35 PM
To: PAUL ROCHE <rochep at comcast.net>
Cc: Jacques Fortin <jacques.f at videotron.ca>; R-390 Mailing List
<r-390 at mailman.qth.net>
Subject: Re: [R-390] Removing Megacycle Change shaft

BTW, great job cleaning those gears!
Barry - N4BUQ

> Thank you all so much, this is the gear I am talking about (I am holding
it);
> doesn’t quite make it into the bushing when meshed with rear small gear of
gear
> assembly #42. I will study Jacques pictures tonight. Yes, the document is
great
> to show you where to put things.
>
> From: Jacques Fortin <jacques.f at videotron.ca>
> Date: Tuesday, June 23, 2026 at 12:14 PM
> To: 'Barry' <n4buq at knology.net>; 'PAUL ROCHE' <rochep at comcast.net>
> Cc: 'R-390 Mailing List' <r-390 at mailman.qth.net>
> Subject: RE: [R-390] Removing Megacycle Change shaft
>
> Hi Barry, Paul,
> Not that simple from the Y2K-3a Chapter 10.
> It make things easier to have another R-390A properly assembled nearby...
> I already sent some pics to Paul, if he still experiencing assembly
problems, I
> can take more pictures from my spare (properly assembled) RF deck.
>
> 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 : 23 juin 2026 11:31
> À : PAUL ROCHE <rochep at comcast.net>
> Cc : R-390 Mailing List <r-390 at mailman.qth.net>
> Objet : Re: [R-390] Removing Megacycle Change shaft
>
> There is a document in the archives that outlines exactly how to assemble
the
> gear train.
>
> https://www.r-390a.net/R-390A-Gear-Rebuild.pdf
>
> 73,
> Barry - N4BUQ
>
>
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