[R-390] R-389 PTO
Paul Anderson
paul at pdq.com
Wed May 6 13:07:47 EDT 2009
Here's my take on it:
Collins relied on at least a few forms of slip mechanisms to act as
mechanical limits to parts of the motor driven tuning systems.
The R-391, which I'm most familiar with, has an internal slip clutch
that is required to act in conjunction with the stop position created
by the locking pin and also by the 10 turn limits. So for example,
the motor will turn the tuner to a 10 turn stop (I think the low end),
then later reverse and turn to the upper stop (determined by where the
lock pin was locked).
In both cases (spinning down to a known lower end, and spinning back
up to the locked position), if the clutch can't slip, the motor will
then be attempting to turn against a jammed mechanism.
If this happens in the R-391, the bronze gear on the motor tears the
teeth off or wrecks the bushings in the line shaft, which is the
common tuning shaft across the three tuning units (two are mechanical,
one is the electromechanical reversing unit).
As it happens, in the R-391, if the slip clutches are fine, then the
limit switches in the electromechanical tuner won't cause damage even
if they fail - it'll just run against the stops, merrily making lots
of noise in the slip clutches.
So in the R-391, and undoubtedly the T-195, and the R-389, the weakest
link is the dried 50 year old grease and oil that causes these slip
clutches to fail. The R-391 clutches can be cleaned, slowly, by
soaking them in kerosene for a week or two, with some toothbrush
action. Most likely an auto parts cleaner would also work, but you
have to be extremely careful around any aluminum, since the cleaner
usually eats aluminum.
Personally, I bought my radios to use them, so I will repair, service
and maintain them so that they can be used as they were originally
done. The R-389 is different enough to me that I need to be careful
before I dive into it.
Paul
On Wed, May 6, 2009 at 12:32 PM, Jerry Boman <mdg11fbf at gmail.com> wrote:
> Hey all,
> This may be slightly off topic but yet not so here goes... I'm a
> newly licensed Gen and have not yet transmitted with my T-195 partly due to
> this thread as it has a auto tune mechanism also and the first time I turned
> it on it took off spinning the dials like it was in a horse race... I was
> shocked and immediatly flipped it off to avoid a catastrophy. Of course
> unlocking the dials solved the immediate worry but in following this thread
> about the R-389 brings me to ask if anyone knows if the T-195 is or might be
> notorious for doing the same thing. Anybody know?. 73 Jerry KD0HNX
>
> On Wed, May 6, 2009 at 9:03 AM, <r-390-request at mailman.qth.net> wrote:
>
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>> Today's Topics:
>>
>> 1. Re: Collins R 389 PTO (Gary Pewitt)
>> 2. Re: Collins R 389 PTO (2002tii)
>> 3. Re: Collins R 389 PTO (Cecil Acuff)
>> 4. PTO makers (wb3fau at att.net)
>> 5. Re: Collins R 389 PTO (2002tii)
>> 6. Re: subchassis mounting nuts Q (Roy Morgan)
>> 7. Re: Collins R 389 PTO (Roy Morgan)
>> 8. Re: subchassis mounting nuts Q (Barry)
>> 9. Re: Collins R 389 PTO (2002tii)
>> 10. R-725 on ebay (Tom M.)
>> 11. Re: PTO makers (Tim Shoppa)
>> 12. Re: Collins R 389 PTO (Gord Hayward)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Tue, 05 May 2009 19:49:12 -0500
>> From: Gary Pewitt <n9zsv at magtel.com>
>> Subject: Re: [R-390] Collins R 389 PTO
>> To: "Cecil Acuff" <chacuff at cableone.net>,
>> <Flowertime01 at wmconnect.com>, <R-390 at mailman.qth.net>
>> Message-ID:
>> <200905060049.n460nDMd005122 at mail962c35.nsolutionszone.com>
>> Content-Type: text/plain; charset="us-ascii"; format=flowed
>>
>> Pardon the possibly off topic question but wouldn't it be at least as
>> important to develop a way to -prevent- the PTO from self distructing
>> in the first place. A better stop, some kind of microswitch
>> controlling a relay to cut the motor, a slip clutch, etc. ? Then you
>> could at least make the still good ones last longer.
>> My 2 cents worth. 73 Gary N9ZSV
>>
>>
>> At 07:17 PM 5/5/2009, Cecil Acuff wrote:
>> >Well if I can find a 389 in reasonable shape with a munched PTO and maybe
>> a
>> >2nd munched PTO that all was also reasonably priced I would be happy to
>> make
>> >an attempt to develop a method to rehabilitate the original PTO's.
>> >
>> >But it appears only functioning 389's are offered for sale...or ones with
>> no
>> >PTO included at all which is no help!
>> >
>> >Cecil Acuff
>> >K5DL
>> >----- Original Message -----
>> >From: <Flowertime01 at wmconnect.com>
>> >To: <R-390 at mailman.qth.net>
>> >Sent: Tuesday, May 05, 2009 4:40 PM
>> >Subject: Re: [R-390] Collins R 389 PTO
>> >
>> >
>> > > Bill,
>> > >
>> > > R389 did run into a to least a couple 1000 built.
>> > > We think there may be 25 units at current time that need a VFO.
>> > >
>> > > Down the other path, what are the chances of mixing core stuff and
>> epoxy
>> > > to
>> > > make a new core?
>> > >
>> > > We could do a cold glue core and machine it to size and thread that
>> would
>> > > fit the shaft.
>> > >
>> > > Then we would have to do a new coil form and wind a coil.
>> > >
>> > > We could select the new core outside diameter to fit a stock core form.
>> > >
>> > > I cannot imagine how many test coils would need to be wound to get the
>> > > inductance and linearity close enough to be usable.
>> > >
>> > > Roger AI4NI
>> > > ______________________________________________________________
>> > > 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
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>> >Help: http://mailman.qth.net/mmfaq.htm
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>> >
>> >This list hosted by: http://www.qsl.net
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>>
>> Gary Pewitt N9ZSV garypewitt at centurytel.net 479 675 4376
>> 1500 French Prairie Rd. Booneville, Arkansas 72927
>> Sturgeon's Law "Ninety percent of everything is crap."
>> Pewitt's Law: But it's that other 10% that makes life worth living."
>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Tue, 05 May 2009 21:00:12 -0400
>> From: 2002tii <bmw2002tii at nerdshack.com>
>> Subject: Re: [R-390] Collins R 389 PTO
>> To: R-390 at mailman.qth.net
>> Cc: R-390 at mailman.qth.net
>> Message-ID: <20090506010018.7206211B7BD at karen.lavabit.com>
>> Content-Type: text/plain; charset="us-ascii"; format=flowed
>>
>> Bob wrote:
>>
>> >any suggestions on usage or PM for [R-389 PTOs] that are still in
>> >good condition?
>>
>> Yes. Clean the drive, with particular attention to the clutch, and
>> make sure the clutch is 100% FB. Then disconnect the wires from the motor.
>>
>> Many people think they have the self-discipline to keep their hands
>> off the motor tuning knob, so they omit the second step. Then they
>> think, "What the hell, once won't matter, I'll be careful," and not
>> long after that they have a mangled PTO.
>>
>> Best regards,
>>
>> Don
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
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>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 3
>> Date: Tue, 5 May 2009 20:18:17 -0500
>> From: "Cecil Acuff" <chacuff at cableone.net>
>> Subject: Re: [R-390] Collins R 389 PTO
>> To: <R-390 at mailman.qth.net>, "2002tii" <bmw2002tii at nerdshack.com>
>> Message-ID: <650572F3F0B84112A16619419B425CAC at acuffmain>
>> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>> reply-type=original
>>
>> Well I have to ask...what was the military standard operating procedure to
>> keep the operators from damaging the things....I can't believe Collins
>> would
>> design a radio that would self destruct in the hands of an operator?
>>
>> I realize I am showing my lack of knowledge of this particular radio but
>> that is less important than understanding how one was to operate the thing
>> as Collins designed and have it survive.
>>
>> Cecil
>> ----- Original Message -----
>> From: "2002tii" <bmw2002tii at nerdshack.com>
>> To: <R-390 at mailman.qth.net>
>> Cc: <R-390 at mailman.qth.net>
>> Sent: Tuesday, May 05, 2009 8:00 PM
>> Subject: Re: [R-390] Collins R 389 PTO
>>
>>
>> > Bob wrote:
>> >
>> >>any suggestions on usage or PM for [R-389 PTOs] that are still in
>> >>good condition?
>> >
>> > Yes. Clean the drive, with particular attention to the clutch, and
>> > make sure the clutch is 100% FB. Then disconnect the wires from the
>> > motor.
>> >
>> > Many people think they have the self-discipline to keep their hands
>> > off the motor tuning knob, so they omit the second step. Then they
>> > think, "What the hell, once won't matter, I'll be careful," and not
>> > long after that they have a mangled PTO.
>> >
>> > Best regards,
>> >
>> > Don
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>> > ______________________________________________________________
>> > 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: 4
>> Date: Wed, 06 May 2009 01:19:46 +0000
>> From: wb3fau at att.net
>> Subject: [R-390] PTO makers
>> To: r-390 at mailman.qth.net
>> Message-ID:
>> <
>> 050620090119.8907.4A00E5B2000A473B000022CB22230704929B0A02D29B9B0EBF9A0E00CC0D99 at att.net
>> >
>>
>>
>> recent issue of this publication shows contractors/builders. I see some
>> with Cosmos PTOs, did they just make PTOS? Did they have a contract
>> for complete receivers? I know Collins
>> built PTOS, did anyone else? Russ wb3fau
>>
>>
>>
>> ------------------------------
>>
>> Message: 5
>> Date: Tue, 05 May 2009 21:41:24 -0400
>> From: 2002tii <bmw2002tii at nerdshack.com>
>> Subject: Re: [R-390] Collins R 389 PTO
>> To: R-390 at mailman.qth.net
>> Message-ID: <20090506014125.E819711B7D0 at karen.lavabit.com>
>> Content-Type: text/plain; charset="us-ascii"; format=flowed
>>
>> Roger wrote:
>>
>> >Down the other path, what are the chances of mixing core stuff and epoxy
>> to
>> >make a new core?
>>
>> Not a chance. For little repairs, yes, but not a whole core (or even
>> a decent chunk of one). The thing to do is find a lump of the right
>> ferrite that is bigger than the core, then machine it to
>> size/shape. If someone shipped a good 70H-1 core to Magnetics, they
>> could probably help to reverse-engineer it.
>>
>> >Then we would have to do a new coil form and wind a coil.
>>
>> The coils and forms should be salvageable, even if they're
>> broken. If not, one could relatively easily duplicate the coil and
>> form if they had a good one to copy.
>>
>> >I cannot imagine how many test coils would need to be wound to get the
>> >inductance and linearity close enough to be usable.
>>
>> I wouldn't dream of trying to re-engineer a PTO that would meet
>> original specs. But I would copy whatever is necessary to repair one
>> to the original design.
>>
>> Best regards,
>>
>> Don
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
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>>
>>
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>>
>>
>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 6
>> Date: Tue, 5 May 2009 22:31:20 -0400
>> From: Roy Morgan <k1lky at earthlink.net>
>> Subject: Re: [R-390] subchassis mounting nuts Q
>> To: Larry Snyder <larrys at teamlarry.com>
>> Cc: R-390 at mailman.qth.net
>> Message-ID: <5509B13C-1045-47DA-9517-7D4E9B2F1DF8 at earthlink.net>
>> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
>>
>>
>> On May 5, 2009, at 8:29 PM, Larry Snyder wrote:
>>
>> > ...My 390A ('58 Motorola + possible mongrel-ism) has
>> > a couple of apparently stripped nuts in the deck where the back end
>> > of the AF chassis attaches. Is there a decent fix for this,
>>
>> Larry,
>>
>> I assume that they are PEM nuts - specially formed nuts that are
>> pressed into the chassis plate. Google PEM Nuts for details and
>> drawings.
>>
>> The problem is that to get a stripped nut out, you have to deform the
>> aluminum that is holding it in, and any replacement nut will not
>> clinch properly. The hole diameter for them to work right is
>> critical. You may be able to add a piece of aluminum below the hole
>> to hole a new PEM nut, but likely there is something below there to
>> prevent that.
>>
>> Roy
>>
>>
>> Roy Morgan
>> k1lky at earthlink.net
>> 529 Cobb St.
>> Groton NY, 13073
>>
>>
>>
>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 7
>> Date: Tue, 5 May 2009 22:33:34 -0400
>> From: Roy Morgan <k1lky at earthlink.net>
>> Subject: Re: [R-390] Collins R 389 PTO
>> To: 2002tii <bmw2002tii at nerdshack.com>
>> Cc: R-390 at mailman.qth.net
>> Message-ID: <70988E2C-8F54-40F4-B2B8-521B9F1CF85E at earthlink.net>
>> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
>>
>>
>> On May 5, 2009, at 9:00 PM, 2002tii wrote:
>>
>> > Bob wrote:
>> >
>> >> any suggestions on usage or PM for [R-389 PTOs] that are still in
>> >> good condition?
>> >
>> > Yes. Clean the drive, with particular attention to the clutch, and
>> > make sure the clutch is 100% FB. Then disconnect the wires from the
>> > motor.
>>
>> AND, make sure the clutch in the manual tuning knob is ok and working
>> right.
>>
>> Is there some other clutch in the system? Or is this the one Don
>> refers to?
>>
>>
>> Roy
>>
>> Roy Morgan
>> k1lky at earthlink.net
>> 529 Cobb St.
>> Groton NY, 13073
>>
>>
>>
>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 8
>> Date: Tue, 5 May 2009 21:41:15 -0500
>> From: "Barry" <n4buq at knology.net>
>> Subject: Re: [R-390] subchassis mounting nuts Q
>> To: <R-390 at mailman.qth.net>
>> Message-ID: <000e01c9cdf4$20c167b0$6401a8c0 at ingrnet.com>
>> Content-Type: text/plain; format=flowed; charset="iso-8859-1";
>> reply-type=original
>>
>> > Hi all --
>> > This may be an old question, but the archives aren't terribly
>> > searchable. My 390A ('58 Motorola + possible mongrel-ism) has
>> > a couple of apparently stripped nuts in the deck where the back end
>> > of the AF chassis attaches. Is there a decent fix for this, or am I
>> > bound for kludgeville?
>> >
>> > Thanx!
>> > -ls-
>>
>> You might be able to drill them out, tap the hole to the appropriate size,
>> and use a theaded insert.
>>
>> Barry - N4BUQ
>>
>>
>>
>> ------------------------------
>>
>> Message: 9
>> Date: Tue, 05 May 2009 22:51:03 -0400
>> From: 2002tii <bmw2002tii at nerdshack.com>
>> Subject: Re: [R-390] Collins R 389 PTO
>> To: R-390 at mailman.qth.net
>> Message-ID: <20090506025104.DF37911B7BD at karen.lavabit.com>
>> Content-Type: text/plain; charset="us-ascii"; format=flowed
>>
>> Cecil wrote:
>>
>> >Well I have to ask...what was the military standard operating
>> >procedure to keep the operators from damaging the things....I can't
>> >believe Collins would design a radio that would self destruct in the
>> >hands of an operator?
>> >
>> >I realize I am showing my lack of knowledge of this particular radio
>> >but that is less important than understanding how one was to operate
>> >the thing as Collins designed and have it survive.
>>
>> PTO failures are generally caused by a confluence of factors -- a
>> sticky clutch, plus running the PTO to its end stop (generally with
>> the motor, but it can happen by hand tuning, too). Back in the day,
>> the clutches were a lot closer to fresh than they are now, they got
>> scheduled maintenance, and everything (switches, limit stops, etc.)
>> was usually in adjustment. Not so anymore, so there is less margin
>> for error than there was back then. Also, the materials in the coil
>> form, the ferrite itself (internal stress cracks), etc. are much more
>> fragile now than they were then. So the next thing that goes wrong
>> could actually be the second or third factor in the confluence, but
>> you won't know it until too late.
>>
>> Don't forget, Uncle Sam had a big pile of replacement PTOs and a
>> never-ending supply of radiomen, so it didn't matter so much if one
>> failed. Now, it does.
>>
>> If you rebuild everything, set all the clearances, stops, etc.
>> perfectly, then perform full depot maintenance twice a year, you may
>> get away with using the motor tuning. In my book, prudence counsels
>> using R-389s as manual-tuned radios in the 21st century -- after the
>> clutches are carefully rebuilt and adjusted, and hopefully everything else.
>>
>> Best regards,
>>
>> Don
>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 10
>> Date: Wed, 6 May 2009 04:27:16 -0700 (PDT)
>> From: "Tom M." <courir26 at yahoo.com>
>> Subject: [R-390] R-725 on ebay
>> To: R-390 at mailman.qth.net
>> Message-ID: <288575.76339.qm at web36208.mail.mud.yahoo.com>
>> Content-Type: text/plain; charset=us-ascii
>>
>>
>> There is a sure enough real R-725 on ebay.
>>
>> 330328126088
>>
>> Tom N5OFF
>>
>>
>>
>>
>>
>>
>>
>> ------------------------------
>>
>> Message: 11
>> Date: Wed, 06 May 2009 08:50:31 -0400
>> From: "Tim Shoppa" <tshoppa at wmata.com>
>> Subject: Re: [R-390] PTO makers
>> To: <wb3fau at att.net>,<r-390 at mailman.qth.net>
>> Message-ID: <4A014F570200003700054E89 at gwiavs.nservices.wmata.com>
>> Content-Type: text/plain; charset=US-ASCII
>>
>> WB3FAU asks:
>> > I see some with Cosmos PTOs, did they just make PTOS?
>> > Did they have a contract for complete receivers?
>>
>> Cosmos Industries made a ham transceiver called the
>> "Cosmophone 35" in the 50's and early 60's. Most striking
>> feature is two long slide rule dials allowing independent
>> settings for two VFO's. I don't think they sold a whole lot of
>> them - in the past few decades I've only ever seen two at
>> hamfests.
>>
>> Tim.
>>
>>
>>
>> ------------------------------
>>
>> Message: 12
>> Date: Wed, 06 May 2009 10:03:49 -0400
>> From: Gord Hayward <ghayward at uoguelph.ca>
>> Subject: Re: [R-390] Collins R 389 PTO
>> To: R-390 at mailman.qth.net
>> Message-ID: <4A0198C5.6080202 at uoguelph.ca>
>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>
>> >
>> >
>> >No, but linearity and absolute rate are both still important because
>> >the VFO needs to be synchronized to the tracking filters (unless you
>> >are willing to tune the RF and VFO independently -- ugh).
>> >
>> AHA, thats the error in my thoughts. At any rate, as a self declared
>> Luddite, I plan to go with
>> mine (R 390A) as is and not mess with it. If (touching wood) something
>> fails, I'll fix it. The
>> advice here is awesome.
>> Cheers, Gord (VE3EOS)
>>
>> --
>>
>> Gordon L. Hayward, Ph.D., P.Eng.,
>> Associate Professor, Biological Engineering,
>> School of Engineering, University of Guelph,
>> Guelph, Ontario, N1G 2W1.
>>
>>
>>
>>
>> ------------------------------
>>
>> _______________________________________________
>> R-390 mailing list
>> R-390 at mailman.qth.net
>> http://mailman.qth.net/mailman/listinfo/r-390
>>
>>
>> End of R-390 Digest, Vol 61, Issue 9
>> ************************************
>>
>
>
>
> --
> "FREEDOM"=The result of intention and action against tyranny. "Live Free -
> Be Free"
> ______________________________________________________________
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