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

[paul swed]

Boy is that the fact. Gotten me a time or 2.

Regards
Paul
WB8TSL

On Fri, Nov 7, 2014 at 9:13 AM, J. L. Trantham <jltran at att.net> wrote:

> Forgot to mention to be sure and check the front panel bulbs.  Frequently
> they burn out and you get no indication when everything is OK.
>
> Good luck.
>
> Joe
>
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of J. L.
> Trantham
> Sent: Thursday, November 06, 2014 8:19 PM
> To: 'Discussion of precise time and frequency measurement'
> Subject: [Bulk] Re: [time-nuts] [Bulk] Re: New Guy, has HP 5061A with
> DATUM 7105A tube seeks advice
>
> Wayne,
>
> Forgot to mention this on my first post.
>
> On the front panel:
>
> 1.  Set the MODE to 'CS OFF'
> 2.  Set OSC FREQUENCY five turn pot to '250' (not COARSE).
> 3.  Set MOD to 'ON'.
> 4.  Set C FIELD to whatever the front door says it should be.
> 5.  Set CIRCUIT CHECK to 'ION PUMP I'.
>
> Plug it in and wait.  ION PUMP I will likely (should) go full scale.  Only
> once it comes close to zero will you be able to advance further.
>
> You can, however, switch CIRCUIT CHECK to its various positions and see
> what the readings are.
>
> BATTERY will not indicate since you removed the battery and charger card.
>
> SUPPLY will indicate about 3/4 scale or a bit more to indicate that the
> 18.7 VDC is OK.
>
> ION PUMP I will likely be 'full scale' but, in my experience, the Datum
> tubes will pump down faster than the HP tubes.  At least give it a couple
> of days.
>
> OSC OVEN will start full scale but will fall to about 3/4 scale as the
> 10811 heats up and comes to its operating temperature.  If it does not come
> down in about 30 to 60 minutes, there is likely a problem with the 10811.
>
> CS OVEN will be at zero until you turn MODE clockwise past CS OFF.  It
> will then go full scale and after 30 to 60 minutes will indicate similar to
> OSC OVEN, assuming everything is OK.
>
> 5 MHZ should be about 2/3 scale.
>
> MULT will not indicate until you flip the AUTO START - START switch to
> START and then let it go back, IIRC.
>
> BEAM I and 2nd HARMONIC will not indicate until you are past CS OFF on the
> MODE switch and the CS OVEN indication comes back down 'on scale'.
>
> CONTROL will indicate when you are in OPER on the MODE switch and have hit
> the LOGIC RESET button once everything is 'on scale', assuming your OSC
> FREQUENCY COARSE is 'in the ball park'.  Once you have had the unit plugged
> in and the OSC OVEN indication has 'come down', you can check the 5 MHz
> against your GPSDO and then adjust the OSC FREQUENCY COARSE to bring it to
> 5.000000 MHz.  Once there, the PLL will likely be able to 'lock' and the
> CONTINOUS OPERATION light should turn green after moving MODE to OPER and
> hitting the LOGIC RESET button but only after all the other meter
> indications are correct.  If the light turns green, it is time for the
> 'happy dance'.
>
> 1 MHz and 100 kHz will indicate after flipping the START switch.
>
> Hope this helps.
>
> Good luck.
>
> Joe
>
>
>
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces at febo.com] On Behalf Of Wayne
> Holder
> Sent: Thursday, November 06, 2014 7:14 PM
> To: Discussion of precise time and frequency measurement
> Subject: [Bulk] Re: [time-nuts] New Guy, has HP 5061A with DATUM 7105A
> tube seeks advice
>
> > If you get the tube working, you should use a counter or Lissajous
> > display with a GPS or rubidium standard to preset it to the correct
> > resonance peak frequency for lockup.  The tube will probably be pretty
> > noisy at first.  If it also has weak beam current, which is common, it
> > will be very difficult to find the right peak without cheating.
> >
>
> I have a Trimble Thunderbolt GPS Disciplined Clock.  Is that going to be
> good enough to set the correct resonance peak frequency for lockup?
>
> BTW, thanks for the link to a source for a manual.  I've ordered a copy
> for my serial number range.
>
> Wayne
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