How to use an EFRATOM 100334-004 Rubidium Oscillator Frequency Standard

[efko31]

Hello,

I am new to the forum and would like to say "hi" and "thank you" for all of you out there who are smarter than me.

I have apparently had an EFRATOM 100334-004 Rubidium Oscillator for over 10 years and had no idea where to start looking for information or help. I do not have any cables or anything else, but I am guessing/hoping someone out there is familiar with this device. If it wasn't for a stroke of dumb luck stumbling across one of these on a Canadian eBay page, it would still be sitting in my closet with me not knowing exactly what it is.

Can someone please help me and inform me how to connect power (I'm assuming +24VDC @ 500-1000mA) to this device through the 25 pin connector and/or some other way? I have included several images of what the inside looks like and I'm surely willing to provide help in any other way I can. Also, there are three TNC connectors, one of which is labeled 10MHz. The other two are unlabeled. Is there any way to figure out what they do?

I do not need any advanced features for this device... just power on and signal (10MHz) out.

Again, any help or redirection is greatly appreciated and thank you.

I look forward to participating in these forums.

--Mark

[bingo600]

PN seems to be an Efratom FRS-C

https://www.tzsupplies.com/efratom-frs-c-10mhz-rubidium-atomic-i4062391/

https://www.eevblog.com/forum/repair/help-needed-for-repair-of-efratom-frs-c-rubidium-oscillator/

https://www.eevblog.com/forum/repair/yabe-yet-another-broken-efratom/

https://www.eevblog.com/forum/testgear/efratom-frs-c-rb-oscillator-teardown/

DOC
https://www.radcomms.net/Efraton_Rubidium_Standard.html
https://wiki.w3axl.com/images/1/1f/Efratom_FRS-C_Rubidium_Oscillator.pdf
https://github.com/MarkFromSales/10MHz-Rb-Ref/blob/master/Efratom_FRS_Manual.pdf


Seems to be the plug
https://www.eevblog.com/forum/projects/dam11w1s-connector-dimensions-(for-srs-prs10)/

[efko31]

Wow thank you so much! This is way more information I had just a couple hours ago. Everything seemed to work except the .jp site on one of the threads and unfortunately the manual link doesn't work.

I really appreciate what you provided me. I can at least get moving in the right direction. Apparently these weren't cheap...

--Mark

[bingo600]

Handy plug pinout - If accurate

https://github.com/MarkFromSales/10MHz-Rb-Ref/blob/master/Efratom_Pinouts.PNG

Maybe a KiCad PCB
https://github.com/MarkFromSales/10MHz-Rb-Ref/tree/master

[efko31]

Bingo,

The manuals DID work... So you get a TON of 'attaboys!   

Can I offer you something in return? I'm not used to asking for help and not returning the favor.

One last thing... the 100334-004 came inside a metal tank bulletproof hazmat box (read: metal). The box has a 25 pin connector and three TNC connectors, one of which is already labeled as 10MHz Out. Obviously not a necessity, but I'd love to keep the unit itself in the metal enclosure. If you come across something that shows this pinout, I'll be insanely happy.

Thank you for all you have provided me!!

--Mark

[bingo600]

Bingo,

The manuals DID work... So you get a TON of 'attaboys!   

Glad it helped

Can I offer you something in return? I'm not used to asking for help and not returning the favor.

No need to ... This is EEV....

One last thing... the 100334-004 came inside a metal tank bulletproof hazmat box (read: metal). The box has a 25 pin connector and three TNC connectors, one of which is already labeled as 10MHz Out. Obviously not a necessity, but I'd love to keep the unit itself in the metal enclosure. If you come across something that shows this pinout, I'll be insanely happy.

I'd keep it in the box too, you do need to attach the Rubi to a Heatsink  OR Metal casing , to keep the Rubi Casing temperature at a sane level (prolongs lifetime)

But it seems like a "Custom casing", I have never seen such a beast ...
Well maybe because most *bay Rubis' are stripped out of the box.

Now you have to start tracing the 25-pin connector to the "inside"  (Maybe use a DMM)
You do have a "Known reference" ... The 15-pin Rubi Plug "pinout"

And maybe post some pics of the case and PCB/Wiring inside.
There are a lot of people here, that have seen/worked with - Weird boxes ....


Edit: Is it like this one ?   ... Still unknown to me , but looks like there might be  "Cleanup Osc" on the PCB ... Fine stuff
https://www.ebay.com/itm/134131949986

[efko31]

Thank you again Bingo.

I think I read somewhere that this was actually a product made for Lucent Technologies. At least, the tank of a box was... the standard of course was used elsewhere I'm sure.

I have posted pictures of the insides in my first post. If it would be helpful to take the whole thing apart and show photographs of both sides of the internal boards, I will do so.

I do of course have a DMM or 6 so should be good to go there.

--Mark

[bingo600]

Se last in my prev post

[efko31]

I glazed right over that somehow... and yes that's exactly what it is, including the box, PCBs, and the standard itself. As you can see there is a DB25 there. If info is available on the housing unit with the DB25 connector, I'd literally jump for joy.

You've given me GREAT stuff to work with. Thank you so much.

--Mark

[bingo600]

Too a closer look at the PICS you posted.
The "OCXO" looking thingy has 15MHz printed on it ...

Wonder if those TNC's give out 15MHz

OCXO Board
I see a possible Altera Pal/Gal "whatever" ?? , a 4060 ripple counter, and a HC4538 monostable multivibrator.
The Altera seems to have quite some legs going to the DB-25 .. Some kind of Freq divider or Control ??

In the end, it might be worth to just "Ditch" the OCXO Print. - Especially if it gives out 15MHz

Then screw a new DB-25 in the chassis hole, solder wires from the DB-25 to the Rubi Base print. Then you'll now the pinout.
Buffer the Rubi 10MHz output x 3 , and replace the 3 TNC's w BNC , and wire the BNC's to the buffer print.


Ohh: And ask a moderator to move this one to the Metrology section, that's where the "Timenuts" live ...

[efko31]

I don't think so. From reading around, it's either a 10MHz sine wave or TTL pulse.

Question... what the heck kind of connector is on the Efratom Unit? 5 pins on a side plus a center pin? I've seen something like this before with 2 or 3 larger pins like that off to the side, but never in a 5-1-5 configuration.

Anyone know what this is called?

--Mark

[bingo600]

Gave a "plug" link above

Seems to be the plug
https://www.eevblog.com/forum/projects/dam11w1s-connector-dimensions-(for-srs-prs10)/

[edpalmer42]

Before you put in time and effort reverse engineering the outer enclosure and its connectors, you might want to check the FRS-C itself and make sure it's healthy.  A few cobbled together connectors and a couple of clip leads and you're good to go.

[efko31]

Bingo and EdPalmer,

Thank you for your continued help and advice. I greatly appreciate it. And you're right Ed, I should test the Frequency Standard first before I go any further. I do have the ability to do that. The frills don't matter if the base unit doesn't work correctly.

--Mark