[time-nuts] Re: 5061A HV Supply, et al. {External}

[Andy Talbot]

I've got three transformers going spare ... :-)

Andy  G4JNT
<http://www.g4jnt.com>IO90IV58AK12 (and others)




On Mon, 14 Nov 2022 at 20:40, Lester Veenstra <m0ycm at veenstras.com> wrote:

> Sacrifice an old microwave oven to the Time Gods for its transformer
>
> GPS: 39.336826 N  78.982287 W (Google)  =                    FM09MI20DU01
> GPS: 39.33682 N  78.9823741 W (GPSDO) =                    FM09MI20CU70



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> -----Original Message-----
> From: Andy Talbot via time-nuts [mailto:time-nuts at lists.febo.com]
> Sent: Monday, November 14, 2022 3:06 PM
> To: Discussion of precise time and frequency measurement
> Cc: Jim Muehlberg; Andy Talbot
> Subject: [time-nuts] Re: 5061A HV Supply, et al. {External}
>
> A simple flyback SMPSU with a Cockcroft-Walton tied on the end will give
> you a simple high voltage supply.  A chain of high value resistors and you
> can even stabilise it.
>
> Andy
> www.g4jnt.com
>
>
>
> On Mon, 14 Nov 2022 at 20:00, Jim Muehlberg via time-nuts <
> time-nuts at lists.febo.com> wrote:
>
> > Rodger,
> >
> > Thanks for the encouragement!  I'm trying not to spend too much effort
> > on this - sort of a distraction from real work.  One would think that
> > NRAO would have a HV power supply lying around somewhere, but astronomy
> > has gone solid state now for decades!  We have a grad student trying to
> > nurse along another 5061 and we'd like to have a pair. I guess I'll
> > slice open the A18 module and see what makes it tick.
> >
> > Thanks again,
> >
> > Jim
> >
> > On 11/10/2022 9:11 AM, Rodger via time-nuts wrote:
> > > Hey Jim,
> > >
> > > I got a 5061a a couple years ago with high ION pump current.  In my
> case
> > the 3500 volts was there but the tube was not pumping down, even after
> > being on for weeks.  I found a Terranova 741 Ion pump power supply on
> eBay
> > for under $100.  It was listed as not working but worked AOK when I got
> > it.  It's a nice supply with variable output voltage, current limiting,
> > safety interlocks, etc.  I hooked it up to the tube and let it run for a
> > few weeks.  Tube pumped down successfully and is working AOK now.  My
> guess
> > is that my A18 wasn't capable of supplying the current needed to pump
> down
> > the tube but the external power supply was.
> > >
> > > Note: I proceeded very carefully with the external supply, letting it
> > run for days at lower voltages and gradually working up to 3500.  Also, I
> > kept the current limit set as low as it would go.  Anyway, it worked for
> > me.  Good luck with yours.
> > >
> > > Rodger
> > >
> > > -----Original Message-----
> > > From: Jim Muehlberg via time-nuts <time-nuts at lists.febo.com>
> > > Sent: Wednesday, November 9, 2022 11:07 AM
> > > To: time-nuts at lists.febo.com
> > > Cc: Jim Muehlberg <jmuehlbe at nrao.edu>
> > > Subject: [time-nuts] 5061A HV Supply, et al.
> > >
> > > I've recently come into possession of a 5061A.  It is claimed that the
> > tube is exhausted, but I'm unwilling to scrap it (horrors!) yet.  I'm not
> > well equipped for HV measurements, but it appears the +3500 V supply is
> not
> > working.  So, I'm hoping the tube just needs to be pumped since it hasn't
> > been powered for years.  Also missing the A3 assembly, but I'll worry
> about
> > that later...
> > >
> > > Anyone willing to part with their A18 or loan it to me?
> > >
> > > Thanks!
> > >
> > --
> >
> > 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
> > F 434.296.0324
> > www.cv.nrao.edu/~jmuehlbe
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