Re: [time-nuts] PRS10 rubidium lamp module failure

[Stewart Cobb]

Follow-up: as several time-nuts noted, there was a lot of corrosion on
parts of the lamp module. Oddly, there was no corrosion on the rest of the
PRS10, or on the TS2500 which it came out of.  The resistor lead was
severely oxidized and partly melted. It's possible that the inductance of
the wire-wound resistor helped sustain an arc. Alternatively, the grounded
lead may have arced to the hot end of the lamp drive coil, although the
coil itself showed very little damage. Perhaps ozone from an arc
accelerated the corrosion. Dunno, it's a mystery.

The resistor is specified at 2W, but it's much smaller than a typical 2W
resistor. I removed the damaged lead and replaced it with a bit of 16 AWG
magnet wire. This gave mechanical support as well as an electrical
connection. Buttoned it all back up and applied power, and the lamp lit
almost immediately (it wasn't lit before) and it locked quickly.  Tuned it
to match a GPSDO, and it seems to be working fine.

A note on tuning: the documentation says that the "SF" tuning command has a
resolution of 1E-12. That's true, but the actual available tuning
resolution seems to be more like 1E-11.

The actual tuning is done by adjusting the C-field with a 12-bit DAC. The
"MR?" command gives the present value of that DAC.  Unfortunately, the full
range of the SF command (4000 counts) only moves the DAC about 600 counts.
You can increment the SF command several times before seeing a response.
Anyone planning to use a PRS10 inside a control loop should be aware of
this quirk.

Cheers!
--Stu
___
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.

Re: [time-nuts] PRS10 rubidium lamp module failure

[Vasco Soares]

I agree with Arthur. It's not possible that such temperature had happened. 
My unit had a severe board and components electrochemical corrosion probably 
caused by a mix of factors as flux residues action and the pcb coating that 
simple dissapear. I think that all together under hot conditions in a small 
enclosure is the most probably reason to that failure. Also, in picture it 
can be seen clearly many spots with electrochemical corrosion.




- Original Message - 
From: "Arthur Dent" <golgarfrinc...@gmail.com>

To: <time-nuts@febo.com>
Sent: Tuesday, May 10, 2016 1:06 AM
Subject: [time-nuts] PRS10 rubidium lamp module failure



..."apparently got hot enough to create a localized thermal runaway in
its lead wire."

I don't think that explanation is correct. There are no signs of
discoloration
caused by overheating anywhere else in the photo and yet the lead wire
has apparently melted as you say. That would probably require at least a
2000 degree temp which would cause lots of damage. Are there any signs
of chemical contamination that could have caused this? Not the same but
In older equipment that had leaky Hg batteries I've seen similar damage.

-Arthur
___
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.



___
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.

Re: [time-nuts] PRS10 rubidium lamp module failure

[Attila Kinali]

On Mon, 9 May 2016 15:47:06 -0700
Stewart Cobb  wrote:

>  A half-melted bit of wire fell
> away before I could take the picture.  Without that heater working, the
> lamp is apparently too cold to start.

This looks more like it corroded away than melted.
Though, it's a bit hard to judge with that angle
and only one picture.


Attila Kinali

-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
___
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.

[time-nuts] PRS10 rubidium lamp module failure

[Arthur Dent]

..."apparently got hot enough to create a localized thermal runaway in
its lead wire."

I don't think that explanation is correct. There are no signs of
discoloration
caused by overheating anywhere else in the photo and yet the lead wire
has apparently melted as you say. That would probably require at least a
2000 degree temp which would cause lots of damage. Are there any signs
of chemical contamination that could have caused this? Not the same but
In older equipment that had leaky Hg batteries I've seen similar damage.

-Arthur
___
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.

Re: [time-nuts] PRS10 rubidium lamp module failure

[Vasco Soares]

Hi,

I had the same problem a few years ago. What kind of advice are your 
searching for to that "usual" failure?


Regards,
VS

- Original Message - 
From: "Stewart Cobb" <stewart.c...@gmail.com>

To: <time-nuts@febo.com>
Sent: Monday, May 09, 2016 11:47 PM
Subject: [time-nuts] PRS10 rubidium lamp module failure



R901, on the far right, is shown on the schematic as "air heater". It
apparently got hot enough to create a localized thermal runaway in its 
lead

wire. There was ample evidence of arcing. A half-melted bit of wire fell
away before I could take the picture.  Without that heater working, the
lamp is apparently too cold to start.

Cheers!
--Stu








___
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. 


___
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.

[time-nuts] PRS10 rubidium lamp module failure

[Stewart Cobb]

R901, on the far right, is shown on the schematic as "air heater". It
apparently got hot enough to create a localized thermal runaway in its lead
wire. There was ample evidence of arcing. A half-melted bit of wire fell
away before I could take the picture.  Without that heater working, the
lamp is apparently too cold to start.

Cheers!
--Stu
___
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.

[time-nuts] PRS10 Rubidium

[Jürg Kögel]

Fellow time nuts. I have two SRS PRS10 Rb’s that I did purchase 10 years
ago. Both have been working for the last nine years. One did fail last year
and I finally got around to looking at it in the last two weeks. The
attached picture shows the trauma to the lamp board. I do not understand
the corrosion since it has been in a very controlled environment in my
basement.

Since the failed unit does have the 1 pps loop control I moved the
processor board to the still working unit. Did not work. Does it take more
than just moving that one board to get 1 pps loop control?

Second any ideas as to what may have happened to the lamp heater board. Any
recommendations? Plan on making a replacement board. Have a power FET MRF134

Thanks



 Juerg
___
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.

Re: [time-nuts] PRS10 Rubidium

[Götz Romahn]

@Juerg,
try swapping the lamp module. This worked with my two PRS10
Goetz

Am 22.02.2015 um 16:44 schrieb Jürg Kögel:

Fellow time nuts. I have two SRS PRS10 Rb’s that I did purchase 10 years
ago. Both have been working for the last nine years. One did fail last year
and I finally got around to looking at it in the last two weeks. The
attached picture shows the trauma to the lamp board. I do not understand
the corrosion since it has been in a very controlled environment in my
basement.

Since the failed unit does have the 1 pps loop control I moved the
processor board to the still working unit. Did not work. Does it take more
than just moving that one board to get 1 pps loop control?

Second any ideas as to what may have happened to the lamp heater board. Any
recommendations? Plan on making a replacement board. Have a power FET MRF134

Thanks



  Juerg


___
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.


___
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.

Re: [time-nuts] PRS10 Rubidium

[Brooke Clarke]

Hi Juerg:

Is it possible you've got a leaking capacitor?

Mail_Attachment --
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
http://www.prc68.com/I/DietNutrition.html
Jürg Kögel wrote:

Fellow time nuts. I have two SRS PRS10 Rb’s that I did purchase 10 years
ago. Both have been working for the last nine years. One did fail last year
and I finally got around to looking at it in the last two weeks. The
attached picture shows the trauma to the lamp board. I do not understand
the corrosion since it has been in a very controlled environment in my
basement.

Since the failed unit does have the 1 pps loop control I moved the
processor board to the still working unit. Did not work. Does it take more
than just moving that one board to get 1 pps loop control?

Second any ideas as to what may have happened to the lamp heater board. Any
recommendations? Plan on making a replacement board. Have a power FET MRF134

Thanks



  Juerg


___
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.


___
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.

Re: [time-nuts] PRS10 Rubidium

[paul swed]

I will speculate the only thing that can release something that would
carrode like that is the tantalum cap on the right. The resistor thats
standing up is simply on some form of insulated standoff?
Regards
Paul
WB8TSL

On Sun, Feb 22, 2015 at 10:44 AM, Jürg Kögel j.koeg...@gmail.com wrote:

 Fellow time nuts. I have two SRS PRS10 Rb’s that I did purchase 10 years
 ago. Both have been working for the last nine years. One did fail last year
 and I finally got around to looking at it in the last two weeks. The
 attached picture shows the trauma to the lamp board. I do not understand
 the corrosion since it has been in a very controlled environment in my
 basement.

 Since the failed unit does have the 1 pps loop control I moved the
 processor board to the still working unit. Did not work. Does it take more
 than just moving that one board to get 1 pps loop control?

 Second any ideas as to what may have happened to the lamp heater board. Any
 recommendations? Plan on making a replacement board. Have a power FET
 MRF134

 Thanks



  Juerg

 ___
 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.

___
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.

Re: [time-nuts] PRS10 Rubidium

[paul swed]

Interesting so it looks like what ever the standoff material is out gassing.
Regards
Paul
WB8TSL

On Sun, Feb 22, 2015 at 2:57 PM, Hans Holzach hans.holz...@gmail.com
wrote:

 hi jürg,

 dispite the fact that my prs-10 has been up and running for only about 2
 years (according to FC!?), the lamp assembly looks pretty ugly (see
 picture) as if it was overheated quite a bit. i bought the unit from ebay,
 so i have no idea under what conditions it had spent its life before i got
 it. the unit works, but the frequency is not as stable as i expected.

 https://farm9.staticflickr.com/8652/16589402796_3a2e1e66c9_o.jpg

 in my opinion the breakout board should work with your second unit. but
 you have to enable the pps PLL (instruction is: PL1). check the manual,
 page 33 ff., also to set the time constant.

 regards,
 hans






 Fellow time nuts. I have two SRS PRS10 Rb’s that I did purchase 10 years
 ago. Both have been working for the last nine years. One did fail last year
 and I finally got around to looking at it in the last two weeks. The
 attached picture shows the trauma to the lamp board. I do not understand
 the corrosion since it has been in a very controlled environment in my
 basement.

 Since the failed unit does have the 1 pps loop control I moved the
 processor board to the still working unit. Did not work. Does it take more
 than just moving that one board to get 1 pps loop control?

 Second any ideas as to what may have happened to the lamp heater board. Any
 recommendations? Plan on making a replacement board. Have a power FET
 MRF134

 Thanks


 ___
 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.

___
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.

Re: [time-nuts] PRS10 Rubidium

[David C. Partridge]

Hmmm is it possible that a nearby board had a wet tantalum capacitor (H2SO4 
electrolyte) that failed spraying acid? 

Dave
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Jürg Kögel
Sent: 22 February 2015 15:44
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] PRS10 Rubidium

I do not understand the corrosion since it has been in a very controlled 
environment in my basement.

___
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.

Re: [time-nuts] PRS10 Rubidium

[Hans Holzach]

hi jürg,

dispite the fact that my prs-10 has been up and running for only about 2 
years (according to FC!?), the lamp assembly looks pretty ugly (see 
picture) as if it was overheated quite a bit. i bought the unit from 
ebay, so i have no idea under what conditions it had spent its life 
before i got it. the unit works, but the frequency is not as stable as i 
expected.


https://farm9.staticflickr.com/8652/16589402796_3a2e1e66c9_o.jpg

in my opinion the breakout board should work with your second unit. but 
you have to enable the pps PLL (instruction is: PL1). check the manual, 
page 33 ff., also to set the time constant.


regards,
hans





Fellow time nuts. I have two SRS PRS10 Rb’s that I did purchase 10 years
ago. Both have been working for the last nine years. One did fail last year
and I finally got around to looking at it in the last two weeks. The
attached picture shows the trauma to the lamp board. I do not understand
the corrosion since it has been in a very controlled environment in my
basement.

Since the failed unit does have the 1 pps loop control I moved the
processor board to the still working unit. Did not work. Does it take more
than just moving that one board to get 1 pps loop control?

Second any ideas as to what may have happened to the lamp heater board. Any
recommendations? Plan on making a replacement board. Have a power FET MRF134

Thanks


___
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.

Re: [time-nuts] PRS10 Rubidium

[Bryan _]

The repair guide for the Efratom LRPO 101 on the K04BB website recommends all 
the tantalums be replaced. 

http://www.ko4bb.com/manuals/index.php?dir=02_GPS_Timing/Efratom
 
-=Bryan=-

Date: Sun, 22 Feb 2015 16:44:06 +0100
From: j.koeg...@gmail.com
To: time-nuts@febo.com
Subject: [time-nuts] PRS10 Rubidium

Fellow time nuts. I have two SRS PRS10 Rb’s that I did purchase 10 years
ago. Both have been working for the last nine years. One did fail last year
and I finally got around to looking at it in the last two weeks. The
attached picture shows the trauma to the lamp board. I do not understand
the corrosion since it has been in a very controlled environment in my
basement.
 
Since the failed unit does have the 1 pps loop control I moved the
processor board to the still working unit. Did not work. Does it take more
than just moving that one board to get 1 pps loop control?
 
Second any ideas as to what may have happened to the lamp heater board. Any
recommendations? Plan on making a replacement board. Have a power FET MRF134
 
Thanks
 
 
 
 Juerg

___
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.
___
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.

Re: [time-nuts] PRS10 rubidium on eBay

[johnk0...@juno.com]

Yep, that's the one, Corby. I'll let Bill know you're not interested. John

-- Original Message --
From: cdel...@juno.com
To: time-nuts@febo.com
Subject: [time-nuts]  PRS10 rubidium on eBay
Date: Sat, 10 May 2014 12:52:20 -0700

John,

I believe that the unit referred to is a Tracor 308A.
I no longer look to play with the Tracor units (304 308 600 900) as their
performance does not merit putting a lot of work into them. Thanks for
the heads up however!
 
The eBay # for the PRS10 is 321402060170

Corby
___
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.

Do THIS before eating carbs #40;every time#41;
1 EASY tip to increase fat-burning, lower blood sugar  decrease fat storage
http://thirdpartyoffers.juno.com/TGL3131/537163f62dd9963f54950st02duc
___
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.

Re: [time-nuts] PRS10 rubidium on eBay

[wb6bnq]

Corby,

It would be nice to have included the eBay item number.

BillWB6BNQ

cdel...@juno.com wrote:


Hi,

I'm selling a nice PRS10 on eBay if anyone is interested.

With manual and schematics.

Works great!

Cheers,

Corby Dawson

___
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.

 



___
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.

Re: [time-nuts] PRS10 rubidium on eBay

[Tom Van Baak]

Hi Bill,

eBay has a search bar. If you type
PRS10 Rubidium
it will locate Corby's item and possibly other similar items.

You can follow this search too, and eBay will send you emails once a day with 
any hits. I have close to a hundred saved search terms on file. See 
www.leapsecond.com/time-nuts.htm for a list of TF company names to search for.

In addition, you can follow this seller in which case you get notified by 
email when the seller has new items. Yes, corbymite is one that I follow.

To answer your question, the item is http://www.ebay.com/itm/321402060170

/tvb

- Original Message - 
From: wb6bnq wb6...@cox.net
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Friday, May 09, 2014 11:50 PM
Subject: Re: [time-nuts] PRS10 rubidium on eBay


 Corby,
 
 It would be nice to have included the eBay item number.
 
 BillWB6BNQ
 
 cdel...@juno.com wrote:
 
Hi,

I'm selling a nice PRS10 on eBay if anyone is interested.

With manual and schematics.

Works great!

Cheers,

Corby Dawson


___
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.

Re: [time-nuts] PRS10 rubidium on eBay

[Dr. David Kirkby]

On 10 May 2014 11:01, Tom Van Baak t...@leapsecond.com wrote:
 Hi Bill,

 eBay has a search bar. If you type
 PRS10 Rubidium
 it will locate Corby's item and possibly other similar items.

I rarely use eBay's search tool now, since I found

http://www.geo-ship.com/

as it is much better at searching eBay than what eBay is!

That allows you to search multiple eBay sites, irrespective of whether

* The seller has paid to make the listing available on multiple sites
* Tell seller posts to your location.

Since even if you pick worldwide on eBay, it does not search all
sites, and it only searches a site if the seller has paid to have
his/her listing on the site.

http://www.geo-ship.com/?c_keywords=11644a%20%28hp,agilent%29c_keywordsTranslated=11644a%20%28hp,agilent%29c_priceRange_min=-1c_priceRange_max=-1c_sellerName=c_category=See-All-Categoriesc_priceOrgCurrencyRange_min=-1c_priceOrgCurrencyRange_max=-1a_selectedLocales=EBAY-US,EBAY-GB,EBAY-AU,EBAY-DE,EBAY-FR,EBAY-IT,EBAY-AT,EBAY-ES,EBAY-ENCA,EBAY-IE,EBAY-NL,EBAY-CH,EBAY-PL,EBAY-SGa_searchDesc=falsea_searchPaypalOnly=falsea_bestOfferOnly=falsea_searchCompleted=falsea_searchSoldOnly=falsea_onlyWithShipping=falsea_setPricerangeTotal=falsea_bidsRange_min=-1a_bidsRange_max=-1a_feedbackRange_min=-1a_feedbackRange_max=-1a_positiveFeedbackRange_min=-1a_positiveFeedbackRange_max=-1a_buyingFormat=Alla_itemCondition=Alla_availableTo=WORLDWIDEa_locatedIn=ANYa_resultsPerPage=100a_ebaySortOrder=StartTimeNewest

Also Google is a good search tool for eBay.

Dave
___
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.

Re: [time-nuts] PRS10 rubidium on eBay

[johnk0...@juno.com]

Corby, a friend of mine has a rubidium standard he wants to sell. I can't 
remember exactly what it is, but I think it's an Austron 504(?) (704?). I sold 
you one many years ago(like 20 or so). They came from one of the ATT microwave 
sites. His number is 308-532-3291 and he lives in North Platte, NE. He's 91 
years old, pretty sharp but nearly blind from macular degeneration and he's 
pretty hard of hearing so he's a bit difficult to talk with. He is on Skype and 
it works better than the landline fone. If you want to try Skype look for 
William O Wesslund. John  

-- Original Message --
From: cdel...@juno.com
To: time-nuts@febo.com
Subject: [time-nuts] PRS10 rubidium on eBay
Date: Fri, 9 May 2014 21:22:34 -0700

Hi,

I'm selling a nice PRS10 on eBay if anyone is interested.

With manual and schematics.

Works great!

Cheers,

Corby Dawson

___
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.

The #1 Worst Carb Ever?
Click to Learn #1 Carb that Kills Your Blood Sugar #40;Don#39;t Eat This!#41;
http://thirdpartyoffers.juno.com/TGL3131/536e7f29de4da7f2961d0st02duc
___
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.

[time-nuts] PRS10 rubidium on eBay

[cdelect]

John,

I believe that the unit referred to is a Tracor 308A.
I no longer look to play with the Tracor units (304 308 600 900) as their
performance does not merit putting a lot of work into them. Thanks for
the heads up however!
 
The eBay # for the PRS10 is 321402060170

Corby
___
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.

[time-nuts] PRS10 rubidium on eBay

[cdelect]

Hi,

I'm selling a nice PRS10 on eBay if anyone is interested.

With manual and schematics.

Works great!

Cheers,

Corby Dawson

___
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.