[R-390] R-390 Digest, Vol 124, Issue 3
Bob Camp
kb8tq at n1k.org
Sun Aug 3 19:54:31 EDT 2014
Hi
First thing is to figure out if the oscillator has stopped oscillating. If the crystal is cracked, or something like that, there’s no oscillator to peak. You can adjust all you want and nothing will happen. I’ve had radios arrive with multiple cracked crystals. My *guess* is that they got dropped on the way to or from here or there. Replace the crystals and all is well ….
Bob
On Aug 3, 2014, at 6:59 PM, Frank Hughes <fsh396ss at gmail.com> wrote:
> Hi,
> This R-390 is the same Hamfest "tailgate special" that I have been working
> on for a while now.
> When it was repaired enough to receive a signal on 3 megacycles, I started
> to see how to get the other bands working, as it was "deaf" on many.
>
> At the time, I did not know if it was just an alignment issue and/or more
> defective components, as we found with the power supply and IF deck.
>
> I have had the crystal deck out, but lost track of which one is in there
> now - my spare? the original?
>
> It is not too difficult to get in and out, except for aligning that goofy
> coupler.
>
> I am going to assume, at the risk of this forum exploding, that using the
> ultrasonic cleaner on the trimmers is "bad" (running for cover now...)
>
> I do have a video training tape from Chuck that contains an explanation of
> how to disassemble and clean a trimmer.
> Looks like there are only about 3472987 of them in the crystal deck.
>
> I would like to be able to test crystals, there is probably some way I can
> use the spectrum analyzer and signal generator to do it.
> I have another method that Roy described using the generator and 410C VTVM
> w/ RF probe, but the scope or the SA/TG would be fun to learn how to do.
>
> Here is what the IF output looks like, I wanted to see if there was a way
> to adjust Z501 using the SA, but no matter how I changed the trimmer and
> coil, it did not effect this trace.
>
> http://i180.photobucket.com/albums/x257/fish1_07/R-390/z501-sa_zps56a0c951.jpg
>
> 73
> Frank
> KJ4OLL
>
>
>
> On Sun, Aug 3, 2014 at 6:19 PM, <r-390-request at mailman.qth.net> wrote:
>
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>> Today's Topics:
>>
>> 1. Re: Ultrasonic cleaning (Roy Morgan)
>> 2. R-390 alignment attempt #1, need advice - Crystal Deck
>> (Frank Hughes)
>> 3. Re: R-390 alignment attempt #1, need advice - Crystal Deck
>> (Bob Camp)
>> 4. Re: R-390 alignment attempt #1, need advice - Crystal Deck
>> (Doug Massey)
>> 5. Re: R-390 alignment attempt #1, need advice - Crystal Deck
>> (Roger Ruszkowski)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Fri, 1 Aug 2014 14:47:49 -0400
>> From: Roy Morgan <k1lky68 at gmail.com>
>> To: Chris Farley <kc9ieq at yahoo.com>
>> Cc: 390 List <r-390 at mailman.qth.net>
>> Subject: Re: [R-390] Ultrasonic cleaning
>> Message-ID: <635A4E5B-6749-4714-8768-F35A502C7FC7 at gmail.com>
>> Content-Type: text/plain; charset=us-ascii
>>
>>
>> On Jul 31, 2014, at 12:42 PM, Chris Farley via R-390 <
>> r-390 at mailman.qth.net> wrote:
>>>
>>>
>>> The antifreeze in a crock pot is a very intriguing idea!! It would both
>> be a mild solvent, and serve to basically steam clean the parts..
>>
>> DO NOT LET ANY DOGS GET TO THE ANTIFREEZE!!
>>
>> One or two licks will KILL a dog. The stuff tastes sweet to them and they
>> like it. Goodbye dog.
>>
>> Roy
>>
>> Roy Morgan
>> RoyMorgan at alum.mit.edu
>> K1LKY Since 1958
>>
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Sun, 3 Aug 2014 16:39:10 -0400
>> From: Frank Hughes <fsh396ss at gmail.com>
>> To: r-390 at mailman.qth.net
>> Subject: [R-390] R-390 alignment attempt #1, need advice - Crystal
>> Deck
>> Message-ID:
>> <CAKLfjC=
>> er-+yqVC83aZf6t-Sd73ykNw9fmPy-MeHANmj0_pGqA at mail.gmail.com>
>> Content-Type: text/plain; charset=UTF-8
>>
>> Hi,
>> I went through the first pass of alignment on the R-390, found some things
>> that need attention, not sure how to proceed.
>>
>> Section 77 , Chapter 3 "Repairs and Adjustments" in TM 11-5820-357-35.
>> "Alignment of Second Crystal Oscillator"
>>
>> Some of the crystals won't adjust w/ the trimmer.
>>
>> Initially did not think this was important, as they are bands I don't use.
>>
>> But by the time I got to the RF deck alignment, it became clear that I will
>> have to fix them.
>>
>> All the manual says is "If no indication is obtained, check the
>> "Crystal-oscillator bandswitch".
>>
>> If the "Crystal-oscillator bandswitch" is the big wafer switch inside the
>> crystal deck, I might be able to get some Deoxit on the wipers/traces, but
>> WOW, that thing is buried.
>>
>> But could the problem also be a dirty trimmer and/or bad crystal?
>>
>> I have a spare crystal deck to swap parts out of, if needed.
>>
>> Thanks & 73
>> Frank
>> KJ4OLL
>>
>>
>> ------------------------------
>>
>> Message: 3
>> Date: Sun, 3 Aug 2014 16:42:02 -0400
>> From: Bob Camp <kb8tq at n1k.org>
>> To: Frank Hughes <fsh396ss at gmail.com>
>> Cc: r-390 at mailman.qth.net
>> Subject: Re: [R-390] R-390 alignment attempt #1, need advice - Crystal
>> Deck
>> Message-ID: <78D8BE67-236B-4148-A3EE-C3EAADD86973 at n1k.org>
>> Content-Type: text/plain; charset=us-ascii
>>
>> Hi
>>
>> Crystals will not adjust or the oscillator is dead on those bands?
>>
>> Bob
>> KB8TQ
>>
>> On Aug 3, 2014, at 4:39 PM, Frank Hughes <fsh396ss at gmail.com> wrote:
>>
>>> Hi,
>>> I went through the first pass of alignment on the R-390, found some
>> things
>>> that need attention, not sure how to proceed.
>>>
>>> Section 77 , Chapter 3 "Repairs and Adjustments" in TM 11-5820-357-35.
>>> "Alignment of Second Crystal Oscillator"
>>>
>>> Some of the crystals won't adjust w/ the trimmer.
>>>
>>> Initially did not think this was important, as they are bands I don't
>> use.
>>>
>>> But by the time I got to the RF deck alignment, it became clear that I
>> will
>>> have to fix them.
>>>
>>> All the manual says is "If no indication is obtained, check the
>>> "Crystal-oscillator bandswitch".
>>>
>>> If the "Crystal-oscillator bandswitch" is the big wafer switch inside the
>>> crystal deck, I might be able to get some Deoxit on the wipers/traces,
>> but
>>> WOW, that thing is buried.
>>>
>>> But could the problem also be a dirty trimmer and/or bad crystal?
>>>
>>> I have a spare crystal deck to swap parts out of, if needed.
>>>
>>> Thanks & 73
>>> Frank
>>> KJ4OLL
>>> ______________________________________________________________
>>> 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: Sun, 3 Aug 2014 18:04:24 -0400
>> From: Doug Massey <dougmassey at masseyradiolabs.com>
>> To: Frank Hughes <fsh396ss at gmail.com>
>> Cc: "r-390 at mailman.qth.net" <r-390 at mailman.qth.net>
>> Subject: Re: [R-390] R-390 alignment attempt #1, need advice - Crystal
>> Deck
>> Message-ID: <B0385B1E-581D-4FD9-8FC6-3CD6509E9965 at masseyradiolabs.com>
>> Content-Type: text/plain; charset=us-ascii
>>
>> Hey frank
>> You may need to pull the whole Crystal deck out. Which is probably not
>> what you wanted to do. Take all the trimmers apart clean them and put them
>> back together. Could be those trimmers are just stuck. It is a common
>> problem with those things. While you're in there you want to clean all
>> those wafers as you pointed out with deoxit. Sometimes the same thing
>> happens adjusting any of the ceramic trimmers in the radio. If you have
>> that assembly apart make sure you check all of them before you put it back
>> together. Overlooking those trimmers while module is out of the radio can
>> sometimes come back to bite you when you do the alignment especially
>> Crystal deck and RF deck
>> Good luck with it. I am sure you will get it going. This is a great
>> group of guys with a lot of experience and great information
>> Doug
>>
>> Doug Massey N4ZZT
>> Massey Radio Labs
>> Johnston SC
>> www.masseyradiolabs.com
>>
>> Sent from my iPhone
>>
>>> On Aug 3, 2014, at 4:39 PM, Frank Hughes <fsh396ss at gmail.com> wrote:
>>>
>>> Hi,
>>> I went through the first pass of alignment on the R-390, found some
>> things
>>> that need attention, not sure how to proceed.
>>>
>>> Section 77 , Chapter 3 "Repairs and Adjustments" in TM 11-5820-357-35.
>>> "Alignment of Second Crystal Oscillator"
>>>
>>> Some of the crystals won't adjust w/ the trimmer.
>>>
>>> Initially did not think this was important, as they are bands I don't
>> use.
>>>
>>> But by the time I got to the RF deck alignment, it became clear that I
>> will
>>> have to fix them.
>>>
>>> All the manual says is "If no indication is obtained, check the
>>> "Crystal-oscillator bandswitch".
>>>
>>> If the "Crystal-oscillator bandswitch" is the big wafer switch inside the
>>> crystal deck, I might be able to get some Deoxit on the wipers/traces,
>> but
>>> WOW, that thing is buried.
>>>
>>> But could the problem also be a dirty trimmer and/or bad crystal?
>>>
>>> I have a spare crystal deck to swap parts out of, if needed.
>>>
>>> Thanks & 73
>>> Frank
>>> KJ4OLL
>>> ______________________________________________________________
>>> 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: 5
>> Date: Sun, 3 Aug 2014 18:19:03 -0400 (EDT)
>> From: Roger Ruszkowski <flowertime01 at wmconnect.com>
>> To: fsh396ss at gmail.com, r-390 at mailman.qth.net
>> Subject: Re: [R-390] R-390 alignment attempt #1, need advice - Crystal
>> Deck
>> Message-ID: <8D17D801121A514-33E0-1E11D at webmail-d234.sysops.aol.com>
>> Content-Type: text/plain; charset="us-ascii"
>>
>>
>> Frank,
>>
>> You did not mention if this R390 was new to you.
>> Or had it worked OK in the past.
>> Or you just do not know if it has worked in the past.
>>
>> It is fixable.
>>
>> But it is an R390.
>>
>> Getting into the crystal deck of the R390 is more complex than on the
>> R390A.
>>
>> The crystals come un seated in the oven and the terminals pins of the
>> crystals get
>> oxidized.
>>
>> And if the receiver was not stored in a heated place and allowed to freeze
>> real good
>> some of the crystals may have given it up.
>>
>> As long as you have to do this maintenance procedure there is no reason to
>> do only part of it.
>>
>> Your going to have to pull the RF deck and the crystal oscillator deck as
>> a pair.
>>
>> You are going to have to open the oven covers (two layers) to get to the
>> crystals.
>> Once you get that far into the receiver you can get to the trimmer caps
>> and the
>> big selector switch.
>>
>> Pull all the crystals and clean (deoxit) the pins and sockets.
>> Clean up the caps but not necessary to disassemble them.
>> Clean up the selector switch contacts.
>>
>> If the missing ones are hit and miss then its likely crystal need sockets
>> and pins cleaned.
>> If every thing drops out on one end or the other it can be selector switch
>> mechanical alignment.
>>
>> As long as you have the RF deck out to get to the crystals you should do
>> the whole RF deck
>> cleaning and lubrication maintenance and check the RF band switch
>> alignment.
>>
>> Worry not about that green gear thing its way over rated.
>> But if you have it use it.
>> If not you will just have to make sure things are aligned as you reinstall
>> the RF deck.
>>
>> Then you can put every thing back together and see how many mega hertz
>> bands you recovered.
>> You can look at the missing mega hertz bands and decide if it a crystal
>> with all of its harmonics missing
>> or a trimmer cap as some of the crystal fundamentals and harmonics are
>> there.
>>
>> And see what is still missing then you can swap in some crystals from your
>> spare deck.
>> Or ask the fellows for some help with the crystals you think you need.
>>
>> Then you can take it all apart again to install the crystals.
>>
>> It Is not hard to do. It is just a slow screw job going both ways and
>> takes time.
>>
>> Moving these receivers down the road takes out more crystals than any
>> thing.
>> The crystals just do not like to be bounced around.
>>
>> Frank if you need some R390 photos put up another post and I will send you
>> some direct
>> from a R390 rebuild I did a couple years ago.
>>
>> It could be worth your time to bread board up a crystal oscillator that you
>> use to check the fundamental of all the crystals with. Just looking at the
>> output level with a scope.
>>
>> Trying to match up the stray capacitance to see if they are on frequency
>> will not be of much value.
>> The crystals will oscillate or not oscillate.
>> Once you get a circuit built up that some crystals work in then you can
>> expect that the ones that do not work are bad.
>>
>> It will be a combination of things. a bad crystal, a dirty trimmer, a
>> loose crystal, an oxidized switch contact.
>>
>> A good maintenance cleaning will cure every thing except the real bad
>> parts.
>> And the few problems that remain will be easy to diagnose and resolve.
>>
>> Roger AI4NI
>>
>>
>> -----Original Message-----
>> From: Frank Hughes <fsh396ss at gmail.com>
>> To: r-390 <r-390 at mailman.qth.net>
>> Sent: Sun, Aug 3, 2014 4:39 pm
>> Subject: [R-390] R-390 alignment attempt #1, need advice - Crystal Deck
>>
>>
>> Hi,
>> I went through the first pass of alignment on the R-390, found some things
>> that need attention, not sure how to proceed.
>>
>> Section 77 , Chapter 3 "Repairs and Adjustments" in TM 11-5820-357-35.
>> "Alignment of Second Crystal Oscillator"
>>
>> Some of the crystals won't adjust w/ the trimmer.
>>
>> Initially did not think this was important, as they are bands I don't use.
>>
>> But by the time I got to the RF deck alignment, it became clear that I will
>> have to fix them.
>>
>> All the manual says is "If no indication is obtained, check the
>> "Crystal-oscillator bandswitch".
>>
>> If the "Crystal-oscillator bandswitch" is the big wafer switch inside the
>> crystal deck, I might be able to get some Deoxit on the wipers/traces, but
>> WOW, that thing is buried.
>>
>> But could the problem also be a dirty trimmer and/or bad crystal?
>>
>> I have a spare crystal deck to swap parts out of, if needed.
>>
>> Thanks & 73
>> Frank
>> KJ4OLL
>> ______________________________________________________________
>> 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
>>
>>
>>
>>
>> ------------------------------
>>
>> Subject: Digest Footer
>>
>> _______________________________________________
>> R-390 mailing list
>> R-390 at mailman.qth.net
>> http://mailman.qth.net/mailman/listinfo/r-390
>>
>>
>> ------------------------------
>>
>> End of R-390 Digest, Vol 124, Issue 3
>> *************************************
>>
> ______________________________________________________________
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