The original photo linked to show 'corrosion' didn't have enough detail to
show what was there plus the tungsten color cast made it impossible to tell
what the correct colors were. I received my 5680A today and after checking
it out as received (9.999,999.99675Mhz after 30 minutes), I removed it
On the FE-5680A, there are two mosfets on the lamp housing - one of
them is purely a heater, and the other is the drive FET for the RF
lamp exciation signal. I assume the designers figured it was going to
run pretty hot anyway and they might as well use the heat for
something useful. In practice,
The LPFRS has 2 heating elements on both tube ends and a crystal "glued" on
the tube.
On Thu, Dec 1, 2011 at 9:46 PM, Steve . wrote:
> Are there any other (mosfet)heaters on the oven cavity? Seems that heating
> from one point is going to create a large temperature gradient which would
> probabl
Are there any other (mosfet)heaters on the oven cavity? Seems that heating
from one point is going to create a large temperature gradient which would
probably effect spatial phase congruency. I believe this problem exists on
the two mosfet configuration as well. Anyway, my idea is to remove the
mos
mance does not have a
> significant impact on the unit's performance.
>
> Bob
>
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of Peter Bell
> Sent: Thursday, December 01, 2011 4:42 AM
> To: Discussion of pre
On 12/01/2011 11:18 AM, Attila Kinali wrote:
>
> Other than that one spot, i have to say that the whole device looks
> like new. No dirt, no corrosion where you'd expect it. Even the solder
> joints look like new.
>
And I did not attempt to clean anything before I took the pictures, either.
T
e time and frequency measurement
Subject: Re: [time-nuts] Heated crystal? & Rb tube corrosion (FE-5680A)
Hi, Steve
Both the lamp and the absorption cell are made out of glass (or
possibly quartz - see attached image). The unit mounted to the
crystal is a PTC thermistor wired directly across o
The referenced photos are poor quality and taken in tungsten lighting
so you really can't see much from them. Here is a photo I just took of
a somewhat similar 5650A that may be new so it is still pretty shiny.
http://farm8.staticflickr.com/7142/6436441767_26980890bb_b.jpg
-Arthur
__
Good afternoon, gentleman,
On Thu, 1 Dec 2011 06:04:22 -0500
"Steve ." wrote:
> Great pictures, by the way.
These are the pictures you have posted :)
> For completeness, I maintain the instruments in an environmental analytical
> laboratory. (Sulfur analyzers, CO2, CHN, Calorimeters, ion chro
All I can say, on a purely practical level, is that every Rb vapor
frequency standard I've ever seen or worked on (starting with the old
Eframtom FRK) has run the lamp at about 100c and the Rb cell at about
80c - the exact temperatures seem to vary a little depending on the
model, but that's how i
Mangus,
Are you sure its is 130c, and not 130f? I can't really cite where i read
it, Maybe the journal of applied physics, but i was under the impression
that we not want to run an Rb oven much beyond 80c. Ideally i believe it
was 50c, but the warm up time was a few weeks.
I'd like to know wh
Attila,
Great pictures, by the way.
My experience with alkaline metal is limited to sodium, potassium and
lithium. Mostly sodium, which after a long process is precipitated from
sodium hydroxide as a reagent. These are all contained in an oven under
very precise temperature and flow control, as
On 12/01/2011 11:18 AM, Attila Kinali wrote:
On Thu, 1 Dec 2011 01:00:44 -0500
"Steve ." wrote:
Note the corrosion around the cheaper metal parts (screws, spacers, shell).
I can't speak for the FE-5680A, but when i see something like this in the
instruments i maintain it's a tale-tale sign gas
On Thu, 1 Dec 2011 05:19:24 -0500
"Steve ." wrote:
> Looking at those pictures with a different mind set, I see now that the
> washers are not corroded as I had suspected. It's amazing how they
> resemble badly corroded washers which are so typically found in ovens in
> which alkalines have leak
I had a bad experience with chinese sellers: I got a Z3815A with the Furuno
GPS enclosure completely rusted and a LPFRS that I suspect was submerged in
water: rusted and corroded internally tough still working... the seller has
agreed to send another one.
On Thu, Dec 1, 2011 at 11:18 AM, Attila Ki
Pete,
Thanks for the pictures. I tend to trust a hermetic quartz or borosilicate
tube.
Looking at those pictures with a different mind set, I see now that the
washers are not corroded as I had suspected. It's amazing how they
resemble badly corroded washers which are so typically found in ovens
On Thu, 1 Dec 2011 01:00:44 -0500
"Steve ." wrote:
> Note the corrosion around the cheaper metal parts (screws, spacers, shell).
> I can't speak for the FE-5680A, but when i see something like this in the
> instruments i maintain it's a tale-tale sign gas mitigation.
I have to agree with Bill th
Hi, Steve
Both the lamp and the absorption cell are made out of glass (or
possibly quartz - see attached image). The unit mounted to the
crystal is a PTC thermistor wired directly across one of the power
supplies. I suspect it's just there to heat up the xtal to a
temperature close to it's knee
Bill,
You did notice that i stated i can't speak for the FE-5680A? All that I
have reference too are pictures at the moment.
My help files? I don't run windows, thanks. But the reason I asked here.
Also, I was under the impression that Rb ovens operated around 80c if the
Rb oven gets that hot
Steve,
I viewed not just the picture you referenced but all of the pictures at that
site
and was unable to detect ANY corrosion of any kind. What you are seeing are
scratch marks in the anodized plating due to having the Rb removed from heavily
plated circuit board that is used as a heat sink fo
Bill,
I was starting to think i may have to crack open an instrument to get a
picture. But i found a reference online.
http://n1.taur.dk/fe5680a-2/IMG_1375.JPG
Note the corrosion around the cheaper metal parts (screws, spacers, shell).
I can't speak for the FE-5680A, but when i see something like
HUH ?
What, exactly, do you mean by "corroded Rb tube interfaces ?"
bILLwb6bnq
"Steve ." wrote:
> snip
>
> Also It appears that quite a few of
> these have corroded Rb tube interfaces.
>
> Thanks,
> Steve
___
time-nuts mailing list -- time-nuts
I've been paying particular attention to the discussions involving the
FE-5680A frequency standards of recent attention. I do not have a FE-5680A
yet, but rather I am studying what is shared from the others prior to
buying. At the very least I want to know what I'm up against should I get a
DOA mod
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