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
Jim
It will be fun to try to save the unit. But indeed the tube may be depleted.
I am pretty sure the 3500 V doesn't come on if the ion pump current is to
high. They are interlocked. If the tubes been off then the ion pump current
should peg and that is a key.
It has to be below about 20 on the ion pump meter.
There is a good bit of detail from KE5FX as I recall on using an external
supply to pump the tube down. Though the voltages are dangerous as a
caution.
You have nothing to lose so have fun trying to recover the unit. No matter
what you will learn good stuff.
Regards
Paul
On Wed, Nov 9, 2022 at 11:48 AM Jim Muehlberg via time-nuts <
time-nuts@lists.febo.com> wrote:
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
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
Jim Muehlberg via time-nuts writes:
Anyone willing to part with their A18 or loan it to me?
Where in the world are you located ?
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
Jim,
When I was working on mine I created a simple voltage divider using a 1GOhm
resistor from Digikey as the high arm (make sure to account for meter input
impedance in the divider design). You'll likely need to check the voltage
with the tube both connected and disconnected as it can load down the
supply if there are any whiskers growing on the ion pump.
I don't have a spare A18 to share, but there is some good material in the
list archives from people that have repaired these power supplies.
Thanks,
Chris
On Wed, Nov 9, 2022 at 10:50 AM Jim Muehlberg via time-nuts <
time-nuts@lists.febo.com> wrote:
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
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
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@lists.febo.com
Sent: Wednesday, November 9, 2022 11:07 AM
To: time-nuts@lists.febo.com
Cc: Jim Muehlberg jmuehlbe@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
time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-leave@lists.febo.com
This procedure is described in the 5061A manual, section 3-15, "Turn-On
After Long Storage."
David N1HAC
On 11/10/22 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@lists.febo.com
Sent: Wednesday, November 9, 2022 11:07 AM
To: time-nuts@lists.febo.com
Cc: Jim Muehlberg jmuehlbe@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!
If one was to build an external 3500 volt supply for this purpose, what sort
of current does it need to be able to deliver?
DaveB, NZ
-----Original Message-----
From: Rodger via time-nuts [mailto:time-nuts@lists.febo.com]
Sent: Friday, November 11, 2022 03:12
To: 'Discussion of precise time and frequency measurement'
Cc: 'Jim Muehlberg'; rodger_adams@yahoo.com
Subject: [time-nuts] Re: 5061A HV Supply, et al.
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@lists.febo.com
Sent: Wednesday, November 9, 2022 11:07 AM
To: time-nuts@lists.febo.com
Cc: Jim Muehlberg jmuehlbe@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
time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an
email to time-nuts-leave@lists.febo.com
time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an
email to time-nuts-leave@lists.febo.com
300 ua is way more then enough.
On Fri, Nov 11, 2022 at 1:17 PM Dave ZL3FJ via time-nuts <
time-nuts@lists.febo.com> wrote:
If one was to build an external 3500 volt supply for this purpose, what
sort
of current does it need to be able to deliver?
DaveB, NZ
-----Original Message-----
From: Rodger via time-nuts [mailto:time-nuts@lists.febo.com]
Sent: Friday, November 11, 2022 03:12
To: 'Discussion of precise time and frequency measurement'
Cc: 'Jim Muehlberg'; rodger_adams@yahoo.com
Subject: [time-nuts] Re: 5061A HV Supply, et al.
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@lists.febo.com
Sent: Wednesday, November 9, 2022 11:07 AM
To: time-nuts@lists.febo.com
Cc: Jim Muehlberg jmuehlbe@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
time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an
email to time-nuts-leave@lists.febo.com
time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an
email to time-nuts-leave@lists.febo.com
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To unsubscribe send an email to time-nuts-leave@lists.febo.com
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@lists.febo.com
Sent: Wednesday, November 9, 2022 11:07 AM
To: time-nuts@lists.febo.com
Cc: Jim Muehlberg jmuehlbe@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
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@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@lists.febo.com
Sent: Wednesday, November 9, 2022 11:07 AM
To: time-nuts@lists.febo.com
Cc: Jim Muehlberg jmuehlbe@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
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com