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

Scott McGrath scmcgrath at gmail.com
Thu Nov 6 19:59:06 EST 2014


Option 4 is the high performance beam tube which traded shorter life for better performance.   It referred to the original tube shipped with the standard 

Not sure about j15 

Sent from my iPhone

> On Nov 6, 2014, at 5:34 PM, Wayne Holder <wayne.holder at gmail.com> wrote:
> 
> Thanks for all the great suggestions.  I was able to unplug and remove the
> battery and, as suggested, also removed the center PCB (battery charger?/
> cutover switch?)
> 
> The back of the unit indicates it has three options installed.  Option 3,
> option 4 and option J15.  Option 3 seems to be the combination of the
> battery option and the time standard option (PPS, etc.), but I'm not sure
> what option 4 and option J15 are.  Can anyone tell me?  Also, the first two
> option stickers (3 & 4) look like they were put on at the factory, as they
> match the serial number label in style (see attached photo.)  However, the
> option J15 sticker is a completely different color (blue) and put only
> slight askew, although it does say "Hewlett Packard" on the bottom of the
> label.
> 
> AS for the suggestions about leaving the unit powered up for a few weeks,
> or more, so it can pump down; I'll give that a try.  However, before I
> power it up, do I need to check anything in particular (cables, switches,
> etc.) to make sure it's ready to be turned on?  I'd hate to break it just
> because I didn't know some needed startup voodoo.
> 
> Wayne
> 
> [image: Inline image 1]
> 
>> On Thu, Nov 6, 2014 at 10:01 AM, paul swed <paulswedb at gmail.com> wrote:
>> 
>> Pete thats quite a hint on the official fumes measurement scale.
>> Frankenstein takes a solid 24 or so hours to your one. So it seems on the
>> CS scale of life you are fumes and I am wisps. The meter shows just about 0
>> photo. Very tough to work with have to play games with meter amplifiers and
>> such.
>> But I do get the green and the darn thing does lock on its own with
>> reasonable 2nd harmonic.
>> So there you go Wayne. Always hope.
>> Regards
>> Paul
>> WB8TSL
>> 
>> On Thu, Nov 6, 2014 at 12:54 PM, Pete Lancashire <pete at petelancashire.com>
>> wrote:
>> 
>>> If after say a week and the current does not go down, there is one more
>>> thing you can do before you have a tube that qualifies as a door stop.
>> You
>>> replace the internal HV supply with 3,500V @ 5 mA I had to do this on
>> mine.
>>> Keep doing it a few minutes at a time, took something like 3 hours.
>>> No drop in current until the very end and all of a sudden the current
>>> starting going down. I put the tube back in the 5061A and after the
>> current
>>> dropped there was enough Cs left to get the thing to work. Just like Paul
>>> I'm sure there is very little left.
>>> 
>>> I turn it on every 3-4 months and let it run for about an hour. The last
>>> few times it took a while to lock and go 'green'
>>> 
>>> -pete
>>> 
>>> 
>>> 
>>> On Wed, Nov 5, 2014 at 11:21 PM, 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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