[R-390] R-390 Digest, Vol 104, Issue 2

frank hughes fsh396ss at gmail.com
Sun Dec 2 07:26:06 EST 2012


Hi Bob,
I found these R-390A training videos to be very helpful, sold by Electric
Radio:

http://www.ermag.com/index.cfm?v_link=catalog&v_product_type_id=26

73
Frank
KJ4OLL

On Sat, Dec 1, 2012 at 10:25 PM, <r-390-request at mailman.qth.net> wrote:

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> Today's Topics:
>
>    1. starting 390A restoration (Bob Young)
>    2. Re: starting 390A restoration (nryan at mchsi.com)
>    3. Re: starting 390A restoration (rbethman)
>    4. Re: starting 390A restoration (rbethman)
>    5. Re: starting 390A restoration (djed1 at aol.com)
>    6. R390a Parts Needed (Mack McCormick)
>    7. Re: starting 390A restoration (nryan at mchsi.com)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Sat, 1 Dec 2012 13:42:50 -0500
> From: Bob Young <bobyoung53 at hotmail.com>
> To: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net>
> Subject: [R-390] starting 390A restoration
> Message-ID: <SNT136-W42A2E7FCA3CAA69B7BEB17CC420 at phx.gbl>
> Content-Type: text/plain; charset="iso-8859-1"
>
>
> I have a Motorola R-390A I bought some years ago and have finally decided
> to start to restore it. It will be my first 390A rebuild. Everything worked
> last time I powered it up but it needs mucho maintenance. I plan on taking
> apart the gear train, lube it adjust it etc with the help of the Y2K manual
> (which looks really well done by the way), also see if the PTO (Motorola)
> can be brought back to within specs without taking a turn off (doubt it,
> it's more than 10 Kc off end to end), recap it, align it and do anything
> else that needs to be done. I am reading (and reading) the R-390A
> Frequently Asked Questions Page but am sure I'll have a lot of questions.
> The first is I pulled the RF deck today to see if it had the death cap
> still in it and it does. I also noticed three or four brown beauties in
> there, probably a stupid question but should I replace those also? Resistor
> checks also? Thanks,
>
> Bob Young
> KB1OKL
>
>
> ------------------------------
>
> Message: 2
> Date: Sat, 1 Dec 2012 13:40:24 -0600 (CST)
> From: nryan at mchsi.com
> To: Bob Young <bobyoung53 at hotmail.com>
> Cc: r-390 at mailman.qth.net
> Subject: Re: [R-390] starting 390A restoration
> Message-ID:
>         <458134067.3576191354390824256.JavaMail.root at dsmdc-mail-mbs11>
> Content-Type: text/plain; charset=utf-8
>
> Hi, Bob,
>
> You're referring to the IF deck, not the RF deck, right?  The IF deck
> contains the "death cap."
>
> You should replace any brown or black plastic-encased tubular caps, but
> keep the metal-encased ones except the "death cap."  That cap should be a
> high quality orange drop rated at 600VDC.
>
> Replace out of spec resistors to optimize the unit and thus gain peace of
> mind.  I use original carbon comp type resistors.
>
> Here's a link to helpful photos of a geartrain teardown from a fellow (I
> think) r-390 list member:
> http://militaryradio.com/R390A/R390RFDeck/
>
> Your PTO make is Motorola, but this link to a Cosmos PTO rebuild may be
> helpful:
> http://r-390.com/cosmos.htm
>
> Good luck,
> Norman
>
> Any activity becomes creative when the doer cares about doing it right, or
> doing it better. -- John Updike
>
>
> ----- Original Message -----
> From: Bob Young <bobyoung53 at hotmail.com>
> To: r-390 at mailman.qth.net
> Sent: Sat, 1 Dec 2012 12:42:50 -0600 (CST)
> Subject: [R-390] starting 390A restoration
>
>
> I have a Motorola R-390A I bought some years ago and have finally decided
> to start to restore it. It will be my first 390A rebuild. Everything worked
> last time I powered it up but it needs mucho maintenance. I plan on taking
> apart the gear train, lube it adjust it etc with the help of the Y2K manual
> (which looks really well done by the way), also see if the PTO (Motorola)
> can be brought back to within specs without taking a turn off (doubt it,
> it's more than 10 Kc off end to end), recap it, align it and do anything
> else that needs to be done. I am reading (and reading) the R-390A
> Frequently Asked Questions Page but am sure I'll have a lot of questions.
> The first is I pulled the RF deck today to see if it had the death cap
> still in it and it does. I also noticed three or four brown beauties in
> there, probably a stupid question but should I replace those also? Resistor
> checks also? Thanks,
>
> Bob Young
> KB1OKL
>
>
> ------------------------------
>
> Message: 3
> Date: Sat, 01 Dec 2012 15:11:47 -0500
> From: rbethman <rbethman at comcast.net>
> To: r-390 at mailman.qth.net
> Subject: Re: [R-390] starting 390A restoration
> Message-ID: <50BA6483.5080409 at comcast.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> The "death cap" is VERY recommended to be 1KV!
>
> You will tempt fate by using a 600VDC.
>
> This is per Chuck Rippel.  If that's not the best reference, I don't
> know what is!
>
> Bob - N0DGN
>
>
>
> ------------------------------
>
> Message: 4
> Date: Sat, 01 Dec 2012 15:19:35 -0500
> From: rbethman <rbethman at comcast.net>
> To: r-390 at mailman.qth.net
> Subject: Re: [R-390] starting 390A restoration
> Message-ID: <50BA6657.6080808 at comcast.net>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> IF filters ceased to grow on trees.
>
> Place an O'scope across light switch, (hot to ground), you'll be amazed
> at the surge spike when turning it on.
>
> 600VDC is NOT adequate!
>
> Bob - N0DGN
>
>
>
> ------------------------------
>
> Message: 5
> Date: Sat, 1 Dec 2012 16:06:33 -0500 (EST)
> From: djed1 at aol.com
> To: nryan at mchsi.com, bobyoung53 at hotmail.com
> Cc: r-390 at mailman.qth.net
> Subject: Re: [R-390] starting 390A restoration
> Message-ID: <8CF9E1EE04DF321-814-41F02 at webmail-d014.sysops.aol.com>
> Content-Type: text/plain; charset="us-ascii"
>
>
>  Good advice on replacing the black/brown beauties, but don't rely too
> much on the PTO article.  The linearity adjustment on the Collins/Motorola
> is substantially different than on the Cosmos.  My advice is to leave the
> linearity alone- adjust the endpoint and take a turn off if needed, but I
> don't recommend trying to adjust the corrector stack.  It usually is pretty
> good after you get the endpoint correct.
> I've recapped mine, but I chickened out on disassembling the gear train.
>  I just flushed it with cleaner and relubed.  But mine wasn't real dirty to
> start with.
> Ed  W2EMN
>
>
>
>
>
> -----Original Message-----
> From: nryan <nryan at mchsi.com>
> To: Bob Young <bobyoung53 at hotmail.com>
> Cc: r-390 <r-390 at mailman.qth.net>
> Sent: Sat, Dec 1, 2012 2:40 pm
> Subject: Re: [R-390] starting 390A restoration
>
>
> Hi, Bob,
>
> You're referring to the IF deck, not the RF deck, right?  The IF deck
> contains
> the "death cap."
>
> You should replace any brown or black plastic-encased tubular caps, but
> keep the
> metal-encased ones except the "death cap."  That cap should be a high
> quality
> orange drop rated at 600VDC.
>
> Replace out of spec resistors to optimize the unit and thus gain peace of
> mind.
> I use original carbon comp type resistors.
>
> Here's a link to helpful photos of a geartrain teardown from a fellow (I
> think)
> r-390 list member:
> http://militaryradio.com/R390A/R390RFDeck/
>
> Your PTO make is Motorola, but this link to a Cosmos PTO rebuild may be
> helpful:
> http://r-390.com/cosmos.htm
>
> Good luck,
> Norman
>
> Any activity becomes creative when the doer cares about doing it right, or
> doing
> it better. -- John Updike
>
>
> ----- Original Message -----
> From: Bob Young <bobyoung53 at hotmail.com>
> To: r-390 at mailman.qth.net
> Sent: Sat, 1 Dec 2012 12:42:50 -0600 (CST)
> Subject: [R-390] starting 390A restoration
>
>
> I have a Motorola R-390A I bought some years ago and have finally decided
> to
> start to restore it. It will be my first 390A rebuild. Everything worked
> last
> time I powered it up but it needs mucho maintenance. I plan on taking
> apart the
> gear train, lube it adjust it etc with the help of the Y2K manual (which
> looks
> really well done by the way), also see if the PTO (Motorola) can be
> brought back
> to within specs without taking a turn off (doubt it, it's more than 10 Kc
> off
> end to end), recap it, align it and do anything else that needs to be
> done. I am
> reading (and reading) the R-390A Frequently Asked Questions Page but am
> sure
> I'll have a lot of questions. The first is I pulled the RF deck today to
> see if
> it had the death cap still in it and it does. I also noticed three or four
> brown
> beauties in there, probably a stupid question but should I replace those
> also?
> Resistor checks also? Thanks,
>
> Bob Young
> KB1OKL
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
>
>
> ------------------------------
>
> Message: 6
> Date: Sat, 1 Dec 2012 17:03:09 -0500
> From: Mack McCormick <w4ax.mack at gmail.com>
> To: R-390 Group <R-390 at mailman.qth.net>
> Subject: [R-390] R390a Parts Needed
> Message-ID:
>         <
> CAFzyUt7iLt12EVFk51Y7G3zwWCBzdQzzQ15ug6vVj_rZLNoMVQ at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> I'm restoring my second R-390a and need two parts please:
>
> 1. On the RF Deck:* Z213 17.5-25.0MC Motorola PN 324D4754 coil assembly*.
> The trimmer capacitor gasket is deforming when turned. Therefore the
> trimmer won't adjust. I've disassembled the trimmer, cleaned, and DeOx'd it
> with poor results. Any other ideas on how to repair the trimmer?
>
> 2. On the back of the rig: The *small cover that protects the 117VAC Power
> cord terminals*.
>
> If you have the* cover or coil assembly for sale* then please contact me
> via PM at w4ax.mack at gmail.com .
>
> Thank you in advance and I'll post pictures after the radio is finished.
> --
> 73,
>
> Mack de W4AX
> http://w4ax.com
>
>
> ------------------------------
>
> Message: 7
> Date: Sat, 1 Dec 2012 21:25:31 -0600 (CST)
> From: nryan at mchsi.com
> To: djed1 at aol.com
> Cc: r-390 at mailman.qth.net
> Subject: Re: [R-390] starting 390A restoration
> Message-ID:
>         <933161969.3609291354418731959.JavaMail.root at dsmdc-mail-mbs11>
> Content-Type: text/plain; charset=utf-8
>
> Hi, Ed,
>
> It's all true what you say about the Motorola corrector stack.  One should
> avoid messing with it.  In my limited experience with them, I've found them
> to be within spec.  I think I read somewhere that a special jig was used in
> their manufacture and the factory's girls found it to be the most difficult
> part of assembling Motorola PTOs.
>
> I should have made clear the reason for sending the PTO link was to give
> one a feel for what's inside a PTO.  If I remember right, the Motorola end
> point coil (where one might have to take off a turn) is similar, though not
> identical, to the Cosmos but the pics give an idea of what's inside.  They
> should help one decide if the work is too daunting to undertake.
>
> While working on the PTO, it's a good idea to disconnect its heater wires
> so as to avoid the bad effects from inadvertently leaving the ovens switch
> on.  The PTO's thermostat can stick and the resulting overheating can
> totally cook the innards.  If the shack is comfortable for humans, ovens
> should be switched off in any case as they likely are intended for extreme
> climate conditions such as inside an unheated shelter or where maximum
> operational stability is required, say, for RTTY gear.
>
> Use extreme care tearing down and reassembling an RF deck geartrain.  Take
> photos and make detailed sketches as you go.  Having another working
> geartrain handy is helpful.  I have found, despite my best efforts, that
> even my pics and sketches may have omitted something and have had to look
> at the working unit.
>
> If you take extra pains, the geartrain should turn silky smooth.  Gently
> debur the split gear faces.  Load gear springs lightly, just sufficiently
> to eliminate backlash.  Lube lightly with Mobil One synthetic oil.
>
> Both those links are worth clicking onto as their content is very well
> written and profusely illustrated.
>
> Have fun!
>
> 73 de Norman
>
> Any activity becomes creative when the doer cares about doing it right, or
> doing it better. -- John Updike
>
>
> ----- Original Message -----
> From: djed1 at aol.com
> To: nryan at mchsi.com, bobyoung53 at hotmail.com
> Cc: r-390 at mailman.qth.net
> Sent: Sat, 1 Dec 2012 15:06:33 -0600 (CST)
> Subject: Re: [R-390] starting 390A restoration
>
>
>  Good advice on replacing the black/brown beauties, but don't rely too
> much on the PTO article.  The linearity adjustment on the Collins/Motorola
> is substantially different than on the Cosmos.  My advice is to leave the
> linearity alone- adjust the endpoint and take a turn off if needed, but I
> don't recommend trying to adjust the corrector stack.  It usually is pretty
> good after you get the endpoint correct.
> I've recapped mine, but I chickened out on disassembling the gear train.
>  I just flushed it with cleaner and relubed.  But mine wasn't real dirty to
> start with.
> Ed  W2EMN
>
>
> -----Original Message-----
> From: nryan <nryan at mchsi.com>
> To: Bob Young <bobyoung53 at hotmail.com>
> Cc: r-390 <r-390 at mailman.qth.net>
> Sent: Sat, Dec 1, 2012 2:40 pm
> Subject: Re: [R-390] starting 390A restoration
>
> Hi, Bob,
>
> You're referring to the IF deck, not the RF deck, right?  The IF deck
> contains
> the "death cap."
>
> You should replace any brown or black plastic-encased tubular caps, but
> keep the
> metal-encased ones except the "death cap."  That cap should be a high
> quality
> orange drop rated at 600VDC.
>
> Replace out of spec resistors to optimize the unit and thus gain peace of
> mind.
> I use original carbon comp type resistors.
>
> Here's a link to helpful photos of a geartrain teardown from a fellow (I
> think)
> r-390 list member:
> http://militaryradio.com/R390A/R390RFDeck/
>
> Your PTO make is Motorola, but this link to a Cosmos PTO rebuild may be
> helpful:
> http://r-390.com/cosmos.htm
>
> Good luck,
> Norman
>
> Any activity becomes creative when the doer cares about doing it right, or
> doing
> it better. -- John Updike
>
>
> ----- Original Message -----
> From: Bob Young <bobyoung53 at hotmail.com>
> To: r-390 at mailman.qth.net
> Sent: Sat, 1 Dec 2012 12:42:50 -0600 (CST)
> Subject: [R-390] starting 390A restoration
>
>
> I have a Motorola R-390A I bought some years ago and have finally decided
> to
> start to restore it. It will be my first 390A rebuild. Everything worked
> last
> time I powered it up but it needs mucho maintenance. I plan on taking
> apart the
> gear train, lube it adjust it etc with the help of the Y2K manual (which
> looks
> really well done by the way), also see if the PTO (Motorola) can be
> brought back
> to within specs without taking a turn off (doubt it, it's more than 10 Kc
> off
> end to end), recap it, align it and do anything else that needs to be
> done. I am
> reading (and reading) the R-390A Frequently Asked Questions Page but am
> sure
> I'll have a lot of questions. The first is I pulled the RF deck today to
> see if
> it had the death cap still in it and it does. I also noticed three or four
> brown
> beauties in there, probably a stupid question but should I replace those
> also?
> Resistor checks also? Thanks,
>
> Bob Young
> KB1OKL
> ______________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-390 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>
>
>
>
>
> ------------------------------
>
> _______________________________________________
> R-390 mailing list
> R-390 at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/r-390
>
>
> End of R-390 Digest, Vol 104, Issue 2
> *************************************
>


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