HP 5370B low frequency modulation
Hej Magnus,
Did you consider switching the 5370 and the 5372 oscillators? Putting the
blame either with the osc or the hosting 5370.
--
Björn
On Mon, July 23, 2007 5:10, Magnus Danielson said:
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Errors-To: time-nuts-bounces+bg=lysator.liu.se+bg=lysator.liu.se@febo.com
From: "Mike Feher" mfeher@eozinc.com
Subject: Re: [time-nuts] HP 5370B low frequency modulation
Date: Sun, 22 Jul 2007 22:58:00 -0400
Message-ID: 00b101c7ccd5$490ae6a0$0201a8c0@gsmacdq14es
Mike,
Highly unlikely, but, possible, especially if it was in a corrosive
atmosphere. Of course then I would expect to see evidence of corrosion
on
other components. When we do not know the answer we can come up with so
many
possibilities and not have one of them correct. I have run across a lot
of
those defective fuses over the years as HP has been using them forever.
There was no real evidence as to why they opened, and that is why before
I
guessed at just plain ageing and the wax eventually getting soft. I just
checked the current flow within the oscillator where the fuse used to be
plugged in, which was at least nice of them, and always found it to be
normal. I just took a piece of buss wire and plugged it into the same
two
pins were the fuse used to be and never had a problem again. The
situation
Magnus describes of course is very unusual, and, in reality would only
be
found by a time nut as it is so miniscule. There is also some
periodicity to
it, which does suggest some control loop problem, but, I would hate to
even
take a guess. - Mike
May I also point out that there may be as low as short low period per 1000
s or
about 3-8 (rought estimate).
I am considering all kinds of possible reasons for it. The group certainly
has
more experience shared among them than I have on these, so I concentrate
on
observations.
I wonder if it may be some form of initial shock burnout that I am
witnessing.
I have no idea how they are suppposed to look. It is not like you want to
toss
your 10811s to the floor just to see how they behave as a result, now is
there?
If I where making them I would, but with a thad more of science attached
to it.
Cheers,
Magnus
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From: Björn_Gabrielsson bg@lysator.liu.se
Subject: Re: [time-nuts] HP 5370B low frequency modulation
Date: Mon, 23 Jul 2007 09:34:35 +0200 (CEST)
Message-ID: 62656.87.227.52.225.1185176075.squirrel@webmail.lysator.liu.se
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Errors-To: time-nuts-bounces+magnus=rubidium.dyndns.org+magnus=rubidium.dyndns.org@febo.com
Hej Magnus,
Hej Björn,
Did you consider switching the 5370 and the 5372 oscillators? Putting the
blame either with the osc or the hosting 5370.
No, good thinking. That would be possible but there is a bit of a logistical
problem prohibiting that as a quick-test. The 5372 sits under a Tek 547 scope
which weighs alot.
Cheers,
Magnus
I have seen cold solder joints on thermal fuses and certain types of
capacitors, while the rest of the instrument was fine with no sign of
corrosion.
I think it has to do with the metal used for certain component leads. Either
they were never soldered well, or interface corrosion developed over time.
Gold plated connectors are a well known example.
Didier KO4BB
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Mike Feher
Sent: Sunday, July 22, 2007 9:58 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] HP 5370B low frequency modulation
Highly unlikely, but, possible, especially if it was in a corrosive
atmosphere. Of course then I would expect to see evidence of corrosion on
other components.
...
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
Hi Didier:
Would you elaborate on the comment "Gold plated connectors are a well known
example." Do you mean when soldered with Lead Tin solder instead of a silver
bearing solder or something else?
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.precisionclock.com
Didier Juges wrote:
); SAEximRunCond expanded to false
Errors-To: time-nuts-bounces+brooke=pacific.net+brooke=pacific.net@febo.com
I have seen cold solder joints on thermal fuses and certain types of
capacitors, while the rest of the instrument was fine with no sign of
corrosion.
I think it has to do with the metal used for certain component leads. Either
they were never soldered well, or interface corrosion developed over time.
Gold plated connectors are a well known example.
Didier KO4BB
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Mike Feher
Sent: Sunday, July 22, 2007 9:58 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] HP 5370B low frequency modulation
Highly unlikely, but, possible, especially if it was in a corrosive
atmosphere. Of course then I would expect to see evidence of corrosion on
other components.
...
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
Magnus,
Have you used your 5372A reference output to drive the 5370B ref in?
Certainly easier than switching 10811As.
Pete Rawson
Brooke Clarke wrote:
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Hi Didier:
Would you elaborate on the comment "Gold plated connectors are a well known
example." Do you mean when soldered with Lead Tin solder instead of a silver
bearing solder or something else?
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.precisionclock.com
Didier Juges wrote:
); SAEximRunCond expanded to false
Errors-To: time-nuts-bounces+brooke=pacific.net+brooke=pacific.net@febo.com
I have seen cold solder joints on thermal fuses and certain types of
capacitors, while the rest of the instrument was fine with no sign of
corrosion.
I think it has to do with the metal used for certain component leads. Either
they were never soldered well, or interface corrosion developed over time.
Gold plated connectors are a well known example.
Didier KO4BB
Brooke
Gold dissolves in the solder and a gold -tin intermetallic compound is
formed which severely reduces the joint integrity and ductility.
This can be circumvented by keeping the gold concentration in the solder
below 4%. Tin plating over the gold before soldering is sometimes used
to ensure this.
Bruce
Maybe some of you haven't seen this oscilloscope clock display yet:
http://www.makezine.com/blog/archive/2007/07/avr_oscilloscope_clock.html
--
Margaret Stephanie Leber CCP, SCJP, SCWCD
http://voicenet.com/~maggie
AOPA 925383 - Amateur Radio Station K3XS - ARRL 39280 - AMSAT 32844
"The art of progress is to preserve order amid change
and to preserve change amid order."-A.N.Whitehead
From: "Pete" peterawson@earthlink.net
Subject: Re: [time-nuts] HP 5370B low frequency modulation
Date: Mon, 23 Jul 2007 08:14:32 -0600
Message-ID: 002601c7cd33$ce56f520$0200a8c0@BASE1
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Errors-To: time-nuts-bounces+magnus=rubidium.dyndns.org+magnus=rubidium.dyndns.org@febo.com
Magnus,
Pete,
Have you used your 5372A reference output to drive the 5370B ref in?
Certainly easier than switching 10811As.
Lack of wiring isle (wrong spelling last time, sorry) prohibited that. It was
just too hard to get to at that moment. As I have another 10811 inside another
instrument I used that as a reference instead. Thanks to fellow time-nut Björn
who I just came home from I have an easier swap-option exercise to do as he was
kind enought to borrow me another 10811 which was easier to get to. Not in
metrical distance thought, but who cares, I was going there anyways. :-)
Anyway, I have no reason to think that the output buffer board would subtract
frequency for length periods of time, up to a minute. It would mean that what
is more or less amplifiers and logical gates would drop cycles with only one
dynamic and one static signal. It is much more reasnoble to assume that the
10811 itself experience some modulation.
Cheers,
Magnus
Brooke,
Thanks Bruce for the quick response, as always.
In my business, we typically dissolve the gold by dipping the solder cup in
a hot tin pot, which is replaced regularly, before soldering the wires. This
has been blessed by the major defense contractors for military applications.
Failure to do this typically results in weakening solder joints over time,
and delayed failures, particularly when there is mechanical and/or thermal
stress applied to the joint.
Didier KO4BB
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Dr Bruce Griffiths
Sent: Monday, July 23, 2007 9:29 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] HP 5370B low frequency modulation
Brooke Clarke wrote:
); SAEximRunCond expanded to false
Errors-To:
time-nuts-bounces+bruce.griffiths=xtra.co.nz+bruce.griffiths=xtra.co.nz@febo
.com
Hi Didier:
Would you elaborate on the comment "Gold plated connectors are a well
known
example." Do you mean when soldered with Lead Tin solder instead of a
silver
bearing solder or something else?
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.precisionclock.com
Didier Juges wrote:
); SAEximRunCond expanded to false
Errors-To:
time-nuts-bounces+brooke=pacific.net+brooke=pacific.net@febo.com
I have seen cold solder joints on thermal fuses and certain types of
capacitors, while the rest of the instrument was fine with no sign of
corrosion.
I think it has to do with the metal used for certain component leads.
Either
they were never soldered well, or interface corrosion developed over
time.
Gold plated connectors are a well known example.
Didier KO4BB
Brooke
Gold dissolves in the solder and a gold -tin intermetallic compound is
formed which severely reduces the joint integrity and ductility.
This can be circumvented by keeping the gold concentration in the solder
below 4%. Tin plating over the gold before soldering is sometimes used
to ensure this.
Bruce
time-nuts mailing list -- time-nuts@febo.com
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https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.
From: "Didier Juges" didier@cox.net
Subject: Re: [time-nuts] HP 5370B low frequency modulation
Date: Mon, 23 Jul 2007 21:12:39 -0500
Message-ID: 000001c7cd98$1c8d3dd0$6601a8c0@didierhp
Brooke,
Thanks Bruce for the quick response, as always.
In my business, we typically dissolve the gold by dipping the solder cup in
a hot tin pot, which is replaced regularly, before soldering the wires. This
has been blessed by the major defense contractors for military applications.
Failure to do this typically results in weakening solder joints over time,
and delayed failures, particularly when there is mechanical and/or thermal
stress applied to the joint.
Gold will dissolve very quickly into the Sn/Pb solder.
If you have a too high gold content in the joint, it can form one of several
Au/Sn mixtures which is brittle and will crack easilly. We had trouble with
that under our BGAs so when the gold layer was too thick, the whole 400-500
ball BGA could crack loose of the board if you accidentilly hit the rather
flimsy cooling flange. On another board we glued a nut to the top of the BGA
and hanged 50-70 kg of it and while the board was clearly bent the BGA was
still firmly hooked to it. Now that's the difference between a few um of gold
too much or not.
There are other cases where the gold-plating is not an issue.
This has been covered in public sources, so a dig around would give some
indication.
Cheers,
Magnus