[R-390] Green wheel on 390

Wed May 12 17:16:11 EDT 2004

Hi Claudio:

I'm going from memory, but, yes, it is not that difficult to re-synch the
the two "halves" of the RF deck.  Don't ask me how I know this -- Oh, well,
I'll tell you anyway -- even though I have the green gear, I had to remove
and reinstall the RF deck once and forgot to install it.  Got it right the
first time around, but when I had to re-do something, I forgot all about it.

How much re-synching is necessary depends on what else, if anything, you did
to the the RF deck.

Some things to watch out for in re-installing the deck:  There are (I
believe) three split gear sets that need to have the backlash set by
off-setting by one, two or three teeth - your choice and depends on any wear
and the springs.  I use a toothpick or similar to hold them in position.
Also, the KC shaft goes through a bushing that mounts to the front plate in
a slotted hole.  If the nut on the bushing was not fully tight and the deck
is set down a bit hard on the bench, the position of the bushing and shaft
can shift upward. There is little room for error.  If the shaft is too high
or too low, either the counter will turn and nothing else, or the gear train
will turn, but the counter won't, etc.  If it is set too low, for example,
the RF deck will appear to be fully seated on the chassis, but not actually
so - the front will be up slightly, resting on the gears.

It's not a bad idea to at least walk through the full mechanical synch after
removing and replacing the RF deck.  The green gear is a convenience to
reduce the amount of work if everything was properly set to start and the
service that was done did not otherwise affect any of the mechanics.  It
does not allow the deck to be mechanically operated off the chassis -- it is
intended to lock everything up in position.  I'm not sure that I'm
explaining this very well, but the point is that, even with the green gear,
things can get out of sorts, so it makes sense to check.

Barry

----- Original Message ----- 
From: "Claudio Spiritelli" <oldradio at tin.it>
To: <r-390 at mailman.qth.net>
Sent: Wednesday, May 12, 2004 4:08 PM
Subject: [R-390] Green wheel on 390

> To All,
>
> after several 390A, I decide to restore a 390(non A).
> I was not aware of the Green wheel and on mine it did not to exist at all.
> Only after I realize that the mechanics was going out of sync, I went into
> Internet and I start to look and I was made aware of the Green wheel.
> TOO LATE
> My question:
> is it sufficient to move the MC shaft to 2   and then move the KC shaft
> until all the cams align perfectly with the lines (including the one
> controlled only by the MC shaft that is already aligned since I have MC on
> 2)?
> Then I can move the dial to the appropriate reading 2. 000.
>
>  It appears to me to simple of  a solution, do I miss something?
> Is here a different procedure to align once the Green wheel is not
installed
> and mechanical alignment is lost?
>
>
> Thank you for your help.
>
> Claudio
>
>
>
> -----Original Message-----
> From: r-390-admin at mailman.qth.net [mailto:r-390-admin at mailman.qth.net]On
> Behalf Of Michael Murphy
> Sent: Friday, May 07, 2004 4:25 AM
> To: D. ball; r-390 at mailman.qth.net
> Subject: Re: [R-390] R-390A IF and AGC
>
>
> Hi Joe,
>
> Back a couple cycles ago I took a stock SSB CB and used it as a tunable IF
> for a 15 Meter Transverter Mobile Rig - worked great.
>
> R390A SSB
> The 6BE6 product detector mod is something I am working on right now with
my
> R390A. I built the circuit using the Electric Radio article (ER-58) parts
> and am finding that it works pretty good. The injection is low and
> distortion occurs during high signal conditions however. Before this, I
did
> the "competition grade" AGC mods that Ray N0DMS published in ER along with
> the stock diode detector mod. The 6BE6 product detector easily beats that
(I
> kept using Rays AGC mod).
>
> Instead of fooling around, I intend to build the product detector stage up
> externally and characterize it "outside the box".  I have collected a
spare
> R390A BFO PTO coil assembly, tube socket, IF can etc.. and am mounting
them
> an a small BUD box. I also collected a variety of pentagrid converter
> candidates which may outperform the 6BE6.
>
> Mike
> WB2UID
>
> ----- Original Message -----
> From: "D. ball" <ke1mb at hotmail.com>
> To: <r-390 at mailman.qth.net>
> Sent: Thursday, May 06, 2004 7:51 PM
> Subject: [R-390] R-390A IF and AGC
>
>
> > Hello all.
> >
> > I have been having great success by using the IF section of a SSB CB to
> > demodulate the RF coming from the 390A's IF out. I cannot say how much
fun
> > it was to do this and watch it work so well. I can also feed the audio
> back
> > into the 390 by using the diode out. Now that I can hear SSB much better
> > than the product detector mod someone installed I am considering
reversing
> > the mod to stock.
> >
> > Question 1: Does anyone think a tube diode makes for better AM audio
than
> a
> > diode?
> >
> > The other is the ACG mods.
> >
> > Question 2: Would the stock AGC work better when the radio is used as a
> down
> > converter rather than the typical AGC mods found in these radios? The CB
> has
> > it's own AGC in the IF stage.
> >
> >
> > On another note I removed a scary mod in the audio section. Someone had
> used
> > a line transformer as a plate transformer!!!!.. Did this guy know
anything
> > about voltage ratings?
> > I removed that mod quickly and lucky there was no damage due to the mod.
> The
> > old caps were replaced with new ones for safty and all works well. I
> bought
> > a 500 to 4 ohm transformer and installed it in the speaker. No need to
> mount
> > a transformer on the back of the radio.
> >
> > thanks
> > Joe
> > KE1MB
> >
> > _________________________________________________________________
> > Express yourself with the new version of MSN Messenger! Download today -
> > it's FREE! http://messenger.msn.com/go/onm00200471ave/direct/01/
> >
> > _______________________________________________
> > R-390 mailing list
> > R-390 at mailman.qth.net
> > http://mailman.qth.net/mailman/listinfo/r-390
>
>
> _______________________________________________
> R-390 mailing list
> R-390 at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/r-390
> ---
> Incoming mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.678 / Virus Database: 440 - Release Date: 5/6/2004
>
> ---
> Outgoing mail is certified Virus Free.
> Checked by AVG anti-virus system (http://www.grisoft.com).
> Version: 6.0.678 / Virus Database: 440 - Release Date: 5/6/2004
>
> _______________________________________________
> R-390 mailing list
> R-390 at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/r-390
>