[time-nuts] Re: Attempting to start HP5061A {External}

[Matt Krick]

The Beam I current rose up to 45 and the front panel clock was 40 minutes
slow since last night but I'm going to reset it and keep an eye on it,
might of just been a glitch in the Matrix.

On Thu, Feb 9, 2023 at 1:00 PM paul swed <paulswedb at gmail.com> wrote:

> Great to hear and with a reading I see in the pix you included thats a
> nice tube.
> Appears to be 38?? Granted the beam current isn't absolute.
> I have a unit with 0 beam current and it still locks and is consistent
> with the other CS units.
> Regards
> Paul
> WB8TSL
>
> On Thu, Feb 9, 2023 at 1:42 AM Matt Krick via time-nuts <
> time-nuts at lists.febo.com> wrote:
>
>> I am pleased to report that the unit is Alive and Ticking!
>>
>> After 30 minutes of the cycling my unit stabilized. I have it another 2
>> hours of CS OFF mode and then started it again this time stable with no
>> cycling.
>>
>> With Loop Open the Beam meter started at 2 and slowly climbed to about 15
>> after about 20 minutes where I did a rough tune.
>>
>> After another 20 minutes I went with Oper mode and centered the coarse
>> tuning getting a peak meter reading of 34. Pegging control to -50
>>
>> I then centered the control reading by again tuning coarse and hit the
>> reset button and got the continuous operation to light.
>>
>> I set the clock to my watch and will compare tomorrow
>>
>> On Wed, Feb 8, 2023, 15:22 Aiden Gibson via time-nuts <
>> time-nuts at lists.febo.com> wrote:
>>
>> > Hi Matt,
>> >
>> > Just to add another 2c to this thread, I went through roughly the same
>> > process Jim describes with my 5061A.
>> >
>> > I also kept the hot wire ionizer powered on in order to catch any
>> neutral
>> > particles which may have been affecting the vacuum.
>> >
>> > I took some measurements of the process to get a rough "pump curve"
>> which
>> > can be seen here:
>> >
>> >
>> >
>> https://docs.google.com/spreadsheets/d/1zsTUAiDZ92Eb-2lID9Hkoe7ByOylcx_LJ3ktGqG_uac/edit?usp=drivesdk
>> >
>> > Best of luck!
>> > -Aiden
>> >
>> > Sent from my Verizon, Samsung Galaxy smartphone
>> >
>> >
>> >
>> > -------- Original message --------
>> > From: Jim Muehlberg via time-nuts <time-nuts at lists.febo.com>
>> > Date: 2/8/23 17:34 (GMT-05:00)
>> > To: Matt Krick via time-nuts <time-nuts at lists.febo.com>
>> > Cc: Jim Muehlberg <jmuehlbe at nrao.edu>
>> > Subject: [time-nuts] Re: Attempting to start HP5061A {External}
>> >
>> > Hi Matt,
>> >
>> > I just went through this when resurrecting a 5061A option 4 that was
>> > about to be scrapped (Horrors!).  My ion pump power supply was flakey,
>> > but after I fiddled with it, I got it to work.  I then saw the same
>> > behaviour.  Ultimately, I connected an external supply to the ion pump
>> > and left it powered for a few days.  This cleaned (or whatever happens)
>> > the tube and I was able to lock it.  FWIW, the supply I connected was
>> > about 7 kV.  The label said 3KV, but apparently that was under the rated
>> > load.  In any event, I thought I wrecked the whole thing.  I was assured
>> > by some time nuts that it was OK, and it was.  It's been running
>> > continuously now for about 2 months.  Here's an ADEV plot for fun...
>> >
>> >    Measured against another opt 4.  Both units have an unknown history,
>> > and they are 40 year old tubes, so I consider this a success!  Good
>> > enough anyway.
>> >
>> > Good luck, and keep one hand in your pocket.
>> >
>> > Jim
>> >
>> > On 2023-02-08 12:39 AM, Matt Krick via time-nuts wrote:
>> > > Hello,
>> > >
>> > > I recently acquired a HP5061A and I am attempting to start it but
>> there
>> > are
>> > > some things that are puzzling me.
>> > >
>> > > Per the manual I have left the unit plugged in for 24 hours with mode
>> set
>> > > to CS OFF set to and I have observed the Ion Pump readings go to 0
>> after
>> > > about 3 or 4 minutes of first plugging it in.
>> > >
>> > > So now I am attempting to power up the tube by switching to Loop open
>> > and I
>> > > can hear another power supply engage. My Ion Pump reading climbs to
>> about
>> > > 30 after about 10 seconds and then the power supply shuts off. Then I
>> get
>> > > into a cycle of about 2 seconds on for 10 seconds off with the Ion
>> Pump
>> > > going between 20-30 or thereabouts.
>> > >
>> > > I'm not sure if this is normal and part of the pumping down process.
>> > > Should I leave it on or keep trying to run it on CS OFF?
>> > >
>> > > Am I correct in assuming that with CS OFF the +3500V supply is running
>> > and
>> > > that is what is acting as the Ion Pump to evacuate the tube, and then
>> > when
>> > > I switch to Loop open that also powers  up the Cesium Heater and the
>> > -2500V
>> > > supply?
>> > >
>> > > I have experience with high power Triodes and Tetrodes where you run
>> the
>> > > filaments without high voltage to help evacuate the tube so I'm unsure
>> > how
>> > > a tube like this operates.
>> > >
>> > > Thank you!
>> > > _______________________________________________
>> > > time-nuts mailing list --time-nuts at lists.febo.com
>> > > To unsubscribe send an email totime-nuts-leave at lists.febo.com
>> > --
>> >
>> > Jim Muehlberg
>> > Senior Engineer
>> >
>> > National Radio Astronomy Observatory
>> > ngVLA Local Oscillator Lead
>> >
>> > 1180 Boxwood Estates Rd B-111
>> > Charlottesville, VA 22903-4602
>> > P 434.296.0270
>> > C 434.422.2017
>> > _______________________________________________
>> > time-nuts mailing list -- time-nuts at lists.febo.com
>> > To unsubscribe send an email to time-nuts-leave at lists.febo.com
>> > _______________________________________________
>> > time-nuts mailing list -- time-nuts at lists.febo.com
>> > To unsubscribe send an email to time-nuts-leave at lists.febo.com
>> >
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at lists.febo.com
>> To unsubscribe send an email to time-nuts-leave at lists.febo.com
>
>