[R-390] More geartrain rebuild info Pseudo Random

[Michael Murphy]

Bob,

I think you are into something good. This could be an addendum to Y2K.
Pseudo Randomization of gears for Spread Spectrum Gear Train Noise Reduction

Mike M. WB2UID

----- Original Message ----- 
From: "Bob Camp" <ham at cq.nu>
To: "Barry" <N4BUQ at aol.com>; "R-390 HF Receiver List"
<r-390 at mailman.qth.net>
Sent: Friday, February 25, 2005 8:41 AM
Subject: Re: [R-390] More geartrain rebuild info


> Hi
>
> Purely as a controlled experiment I have *also* done the gear shuffle.
> They do go back together fairly well when you randomize them.
>
> The real trick is to put it all together and then rotate it. It should
> spin freely with no binding. If you have a point that it binds at then
> there is a gear mismatch or bur somewhere.
>
> On page 3-23 of the Y2K manual there is an interesting block diagram of
> the RF deck gear train. The gizmo we call the planetary gear is called
> out as a differential in the drawing. On page 3-26 section 4 goes into
> all the messy details of the beast. Bottom line - yes it is driven by
> both the KC and MC knobs to allow you to tune to both the correct KHz
> and MHz.
>
> My main concern with the planetary is that it is very much driven off
> of the KC knob. Because of that any drag is noticeable as you tune in a
> signal. If you want one of these radios that will tune from one end of
> a sub band to the other with a single twist of the KC knob then the
> planetary needs to be in pretty darn good shape.
>
> Take Care!
>
> Bob Camp
> KB8TQ
>
>
>
> On Feb 24, 2005, at 11:17 PM, Barry wrote:
>
> > Well, I suppose I'm outta luck on this one.  I've played musical gears
> > with
> > them already so there's no way for me to tell which one's mate is
> > which.  I
> > just hope any effect will be minimal.
> >
> > Also, does the planetary gear revolve on KC changes or is it only on
> > MC?  I
> > can't see the geartrain on my other radio to tell.
> >
> > Barry(III) - N4BUQ
> >
> >
> >> Hi
> >>
> >> I very much agree that a gear train with a reasonable amount of crud
> >> in
> >> it probably will require the planetary gears be torn down. When you do
> >> the only way to really get them clean is to take them down to pieces
> >> and clean each one.
> >>
> >> The obvious gotcha is how do I get these back together with only two
> >> hands and a limited number of toes involved. Cleverly bent paper clips
> >> seem to be the "other" way to do this if you don't have access to
> >> stuff
> >> like plastic hemostats.
> >>
> >> Here's an issue that's a little more subtle. The gears probably left
> >> the factory all nice and uniform. When they did you could swap any
> >> "top" with any "bottom" and there would be no net effect at all. Over
> >> the years each "top" has rubbed against it's respective "bottom" for a
> >> really long time. Essentially you have created matched pairs of gear
> >> halves.
> >>
> >> So in addition to needing a number of fingers and toes to put it all
> >> back together you also need three sets of eyes to make sure all the
> >> sets remain with each other.
> >>
> >> The gear will work pretty darn well even if you randomize the gears.
> >> My
> >> story is that it was a controlled experiment and I'm sticking to it.
> >> If
> >> you want a silky smooth gear set when you are done it seems to be best
> >> to keep everything in order ....
> >>
> >>     Enjoy!
> >>
> >>         Bob Camp
> >>         KB8TQ
> >>
> >>
> >>
> >> On Feb 23, 2005, at 10:19 PM, Barry wrote:
> >>
> >>> List,
> >>>
> >>> In the process of tearing down this geartrain, I noticed the
> >>> planetary
> >>> gears
> >>> were quite clogged with grease.  Scott's slide show says it probably
> >>> isn't
> >>> necessary to tear the planetary gears apart, but it didn't appear I
> >>> would
> >>> get this one clean unless I did and I'm sure glad I did.
> >>>
> >>> Upon taking apart the three split gears, all three exhibited a fair
> >>> amount
> >>> of drag when I twisted them against each other.  Upon closer
> >>> inspection, I
> >>> could see small burrs on the teeth.  After removing these burrs, the
> >>> gears
> >>> ride smoothly against each other.  I would never have known this
> >>> unless I
> >>> disassembled them.  Also, it gives me a good chance to ensure a lot
> >>> of
> >>> the
> >>> hardened grease and dirt is removed.  After a 24-hour soaking in
> >>> kerosene,
> >>> there was still a significant amount of grime in this assembly.
> >>>
> >>> Now if I can figure out how to get four split gears all tensioned and
> >>> reassembled at the same time!
> >>>
> >>> Barry(III) - N4BUQ
> >>>
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> >>
> >>
> >
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