[time-nuts] [Bulk] Re: New Guy, has HP 5061A with DATUM 7105A tube seeks advice

Scott McGrath scmcgrath at gmail.com
Thu Nov 6 08:39:40 EST 2014


The datum tubes are fairly common as they were significantly less expensive than HP/Agilent tubes and lasted longer 

First thing as JL notes is to remove battery and charger 

Just power it up and monitor the ion pump value on the test meter if it drops to zero fairly rapidly the tube may still be good

Depending on length of storage this may take up to a week to settle to zero



Sent from my iPhone

> On Nov 6, 2014, at 7:54 AM, "J. L. Trantham" <jltran at att.net> wrote:
> 
> I agree.  Plug it in and see what happens although I would probably disconnect and remove the NiCd batteries and inspect for and clean up any leakage issues.  I would also remove A2, the battery charger board, until initial tests are completed.  A2 is the center board seen from the bottom.
> 
> I suspect the plug you have is correct.  You probably have to disassemble it, rotate the 'insert' to the proper orientation for the socket on the back, 'file out' a small 'ridge' in the proper 'orientation groove'  on the 'insert' that will allow the 'insert' to be reinstalled in the 'housing', then reassemble the plug.  Make sure the electrical pins and sockets 'line up' (A to A, B to B, and G to G) between the insert and the socket on the back of the unit.  I had to do that on mine.
> 
> Good luck.
> 
> Joe
> 
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Azelio Boriani
> Sent: Thursday, November 06, 2014 6:39 AM
> To: Discussion of precise time and frequency measurement
> Subject: [Bulk] Re: [time-nuts] New Guy, has HP 5061A with DATUM 7105A tube seeks advice
> 
> It is not uncommon that replacement tubes are not the original ones. See here:
> <http://www.gigatest.net/datum/cesium_tubes.pdf>
> You can't do anything else than plugging it in and check the various voltages. If there is any life left in the tube and the ion pump is working, you can even experience a locked status in hours (tens of hours, maybe).
> 
>> On Thu, Nov 6, 2014 at 8:21 AM, Wayne Holder <wayne.holder at gmail.com> wrote:
>> I recently picked up a 5061A surplus, but have no idea whether it 
>> works or not.  The first hurdle is getting a power cord, but I'm still 
>> waiting for the proper connector to show up (the first one I ordered 
>> had the wrong orientation on the 3 pins.)  In the meantime, I've been 
>> reading though what materials I can find online in order to figure out 
>> how to  try and safely turn it on and see if the tube is OK, or dead.
>> 
>> However after removing the top cover, I can see that my unit doesn't 
>> seem to contain the typical kind of cesium tube assembly I see in the 
>> HP docs I've found online.  Instead, it has a tube made by DATUM with 
>> the following markings on the label:
>> 
>> Model: 7105A
>> Serial: 9951991226
>> Part No: 03667-501
>> Oven Temp: 92 degrees C
>> Oven Monitor Therm: 101 Ohms
>> EMV: 2000 DC
>> NSN ______ 5960 01214 7475
>> 
>> Can anyone tell me about this model and why it might have a DATUM tube 
>> rather than the kind I see in the HP oc?  Also, any advice on how to 
>> safely check it out?
>> 
>> I bought this thing out of curiosity but, upon looking inside at all 
>> the various dials and switches and multi-turn potentiometers, I find 
>> I'm rather intimated by it, even though I have a fairly decent 
>> background in electronics.
>> 
>> Wayne
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