5061A HV Supply, et al.
Jim
I may be missing something here. Your suggesting the 3500 V ion pump supply
is bad.
But I believe the ion pump meter is pegged from an earlier post. If true
then the 3500 V is fine. If the tubes dirty and drawing too much current
there is a lockout circuit on a15 that will not allow the CS oven and 2500
V to come up until the ion pump is below about 15-20ua on the meter. It
senses the current being drawn by the 3500 HV. Enters a15 on pin 1 and
inhibits the rest of the system.
If my thoughts are correct then you need to pump down the tube as Rodger
says with a 3500 V supply and as I suggested 300 ua is way more than
enough. There is a chance the tube may work in a relative quality sense.
That is it could lock but there are so few Cs that the output of the system
is noisy.
Regards
Paul
WB8TSL
On Mon, Nov 14, 2022 at 3:00 PM 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
Sacrifice an old microwave oven to the Time Gods for its transformer
Lester B Veenstra K1YCM MØYCM W8YCM 6Y6Y W8YCM/6Y 6Y8LV (Reformed USNSG
CTM1)
lester@veenstras.com
452 Stable Ln
Keyser WV 26726 USA
GPS: 39.336826 N 78.982287 W (Google)
GPS: 39.33682 N 78.9823741 W (GPSDO)
Telephones:
Home: +1-304-289-6057
US cell +1-304-790-9192
Jamaica cell: +1-876-456-8898
-----Original Message-----
From: Andy Talbot via time-nuts [mailto:time-nuts@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@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
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
I've got three transformers going spare ... :-)
Andy G4JNT
http://www.g4jnt.comIO90IV58AK12 (and others)
On Mon, 14 Nov 2022 at 20:40, Lester Veenstra m0ycm@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
Telephones:
Home: +1-304-289-6057
US cell +1-304-790-9192
Jamaica cell: +1-876-456-8898
-----Original Message-----
From: Andy Talbot via time-nuts [mailto:time-nuts@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@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
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
Of course a small “Variac” on the primary will get the voltage to what you want
Lester B Veenstra K1YCM MØYCM W8YCM 6Y6Y W8YCM/6Y 6Y8LV (Reformed USNSG CTM1)
mailto:lester@veenstras.com lester@veenstras.com
452 Stable Ln
Keyser WV 26726 USA
GPS: 39.336826 N 78.982287 W (Google)
GPS: 39.33682 N 78.9823741 W (GPSDO)
Telephones:
Home: +1-304-289-6057
US cell +1-304-790-9192
Jamaica cell: +1-876-456-8898
From: Andy Talbot [mailto:andy.g4jnt@gmail.com]
Sent: Monday, November 14, 2022 3:44 PM
To: Lester Veenstra
Cc: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Re: 5061A HV Supply, et al. {External}
I've got three transformers going spare ... :-)
Andy G4JNT
IO90IV58AK12 (and others)
On Mon, 14 Nov 2022 at 20:40, Lester Veenstra m0ycm@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
Telephones:
Home: +1-304-289-6057
US cell +1-304-790-9192
Jamaica cell: +1-876-456-8898
-----Original Message-----
From: Andy Talbot via time-nuts [mailto:time-nuts@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@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
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
Paul,
My understanding is that the 3500 V is on as soon as power is applied.
Disconnected, I get 750V at the HV lead. I first connected a 1M Ohm
resistor divider because I don't really have HV measuring stuff (10K to
- and it read 350 V. Indeed the meter is pegged, but I suspect that is
due to some internal fault in the A18 as well. So unless there is some
turn on signal to the 3500 V supply, I suspect it is bad. This whole
thing may be a basket case. No one knows the history.
I'm also missing the divider assembly, so that may put the brakes on the
whole project, but I'll worry about that once I have attempted to pump down.
Thanks for the advice!
Jim
On 11/14/2022 3:25 PM, paul swed via time-nuts wrote:
Jim
I may be missing something here. Your suggesting the 3500 V ion pump supply
is bad.
But I believe the ion pump meter is pegged from an earlier post. If true
then the 3500 V is fine. If the tubes dirty and drawing too much current
there is a lockout circuit on a15 that will not allow the CS oven and 2500
V to come up until the ion pump is below about 15-20ua on the meter. It
senses the current being drawn by the 3500 HV. Enters a15 on pin 1 and
inhibits the rest of the system.
If my thoughts are correct then you need to pump down the tube as Rodger
says with a 3500 V supply and as I suggested 300 ua is way more than
enough. There is a chance the tube may work in a relative quality sense.
That is it could lock but there are so few Cs that the output of the system
is noisy.
Regards
Paul
WB8TSL
On Mon, Nov 14, 2022 at 3:00 PM 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
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@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
F 434.296.0324
www.cv.nrao.edu/~jmuehlbe
Jim
OK I thought the thread said the meter is pegged and yes at turn on the ion
pump 3500 V is always on. The switching and protection I am speaking about
is for the other circuits. They will not start if the pump current is to
high. The ION pump sends a signal that inhibits their start. A 1M R is far
too low of a resistance its loading the supply down. Try something like
40-60 Meg. Maybe a string of 10 M with a 100k R at the bottom. Measure the
V across the 100K. In normal operation the 3500 V will be drawing 4-14ua if
the tubes reasonably pumped down.
So thinking about this. There is a twist HV connector on the chassis that
the 3500 V goes through. I am reluctant to say this but if that were off
and far away from anything to arc to and the ion pump meter went to close
to zero then you would know the supply is most likely working and you have
a very dirty tube. I just do not like the thought of a 3500 V plug floating
free.
Regards
Paul
WB8TSL
On Mon, Nov 14, 2022 at 7:51 PM Jim Muehlberg via time-nuts <
time-nuts@lists.febo.com> wrote:
Paul,
My understanding is that the 3500 V is on as soon as power is applied.
Disconnected, I get 750V at the HV lead. I first connected a 1M Ohm
resistor divider because I don't really have HV measuring stuff (10K to
- and it read 350 V. Indeed the meter is pegged, but I suspect that is
due to some internal fault in the A18 as well. So unless there is some
turn on signal to the 3500 V supply, I suspect it is bad. This whole
thing may be a basket case. No one knows the history.
I'm also missing the divider assembly, so that may put the brakes on the
whole project, but I'll worry about that once I have attempted to pump
down.
Thanks for the advice!
Jim
On 11/14/2022 3:25 PM, paul swed via time-nuts wrote:
Jim
I may be missing something here. Your suggesting the 3500 V ion pump
supply
is bad.
But I believe the ion pump meter is pegged from an earlier post. If true
then the 3500 V is fine. If the tubes dirty and drawing too much current
there is a lockout circuit on a15 that will not allow the CS oven and
2500
V to come up until the ion pump is below about 15-20ua on the meter. It
senses the current being drawn by the 3500 HV. Enters a15 on pin 1 and
inhibits the rest of the system.
If my thoughts are correct then you need to pump down the tube as Rodger
says with a 3500 V supply and as I suggested 300 ua is way more than
enough. There is a chance the tube may work in a relative quality sense.
That is it could lock but there are so few Cs that the output of the
system
is noisy.
Regards
Paul
WB8TSL
On Mon, Nov 14, 2022 at 3:00 PM 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
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@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
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
Jim,
The 3500V supply is designed to be a soft supply that folds under load. A
1MOhm load is enough to make it collapse down to 750V. The meter display
estimates current by measuring how much the voltage sags.
If you want to measure open circuit voltage you'll need to get closer to a
1GOhm measurement impedance. If you want to crosscheck the current through
the ion pump you can unmount the tube and connect an ammeter between it and
the chassis (the return path for the ion pump) and measure the current
directly.
Thanks,
Chris
On Mon, Nov 14, 2022, 6:51 PM Jim Muehlberg via time-nuts <
time-nuts@lists.febo.com> wrote:
Paul,
My understanding is that the 3500 V is on as soon as power is applied.
Disconnected, I get 750V at the HV lead. I first connected a 1M Ohm
resistor divider because I don't really have HV measuring stuff (10K to
- and it read 350 V. Indeed the meter is pegged, but I suspect that is
due to some internal fault in the A18 as well. So unless there is some
turn on signal to the 3500 V supply, I suspect it is bad. This whole
thing may be a basket case. No one knows the history.
I'm also missing the divider assembly, so that may put the brakes on the
whole project, but I'll worry about that once I have attempted to pump
down.
Thanks for the advice!
Jim
On 11/14/2022 3:25 PM, paul swed via time-nuts wrote:
Jim
I may be missing something here. Your suggesting the 3500 V ion pump
supply
is bad.
But I believe the ion pump meter is pegged from an earlier post. If true
then the 3500 V is fine. If the tubes dirty and drawing too much current
there is a lockout circuit on a15 that will not allow the CS oven and
2500
V to come up until the ion pump is below about 15-20ua on the meter. It
senses the current being drawn by the 3500 HV. Enters a15 on pin 1 and
inhibits the rest of the system.
If my thoughts are correct then you need to pump down the tube as Rodger
says with a 3500 V supply and as I suggested 300 ua is way more than
enough. There is a chance the tube may work in a relative quality sense.
That is it could lock but there are so few Cs that the output of the
system
is noisy.
Regards
Paul
WB8TSL
On Mon, Nov 14, 2022 at 3:00 PM 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
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@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
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
Here is a pix of a unit I was testing.
[image: DSC04636.JPG]
The current meter is in the lower leg of the return. You can see the high
voltage probe on the right. I recall its 68 M and feeds a fluke DVM. The
amp meter is measuring the current that the probe is consuming. The other
connections are ground and +18.7V.
The precision voltage divider in the background was not used.
Testing the supply like this is fairly easy and just look at the schematics
to understand how to hook everything up.
Regards
Paul
WB8TSL
On Mon, Nov 14, 2022 at 9:27 PM paul swed paulswedb@gmail.com wrote:
Jim
OK I thought the thread said the meter is pegged and yes at turn on the
ion pump 3500 V is always on. The switching and protection I am speaking
about is for the other circuits. They will not start if the pump current is
to high. The ION pump sends a signal that inhibits their start. A 1M R is
far too low of a resistance its loading the supply down. Try something like
40-60 Meg. Maybe a string of 10 M with a 100k R at the bottom. Measure the
V across the 100K. In normal operation the 3500 V will be drawing 4-14ua if
the tubes reasonably pumped down.
So thinking about this. There is a twist HV connector on the chassis that
the 3500 V goes through. I am reluctant to say this but if that were off
and far away from anything to arc to and the ion pump meter went to close
to zero then you would know the supply is most likely working and you have
a very dirty tube. I just do not like the thought of a 3500 V plug floating
free.
Regards
Paul
WB8TSL
On Mon, Nov 14, 2022 at 7:51 PM Jim Muehlberg via time-nuts <
time-nuts@lists.febo.com> wrote:
Paul,
My understanding is that the 3500 V is on as soon as power is applied.
Disconnected, I get 750V at the HV lead. I first connected a 1M Ohm
resistor divider because I don't really have HV measuring stuff (10K to
- and it read 350 V. Indeed the meter is pegged, but I suspect that is
due to some internal fault in the A18 as well. So unless there is some
turn on signal to the 3500 V supply, I suspect it is bad. This whole
thing may be a basket case. No one knows the history.
I'm also missing the divider assembly, so that may put the brakes on the
whole project, but I'll worry about that once I have attempted to pump
down.
Thanks for the advice!
Jim
On 11/14/2022 3:25 PM, paul swed via time-nuts wrote:
Jim
I may be missing something here. Your suggesting the 3500 V ion pump
supply
is bad.
But I believe the ion pump meter is pegged from an earlier post. If true
then the 3500 V is fine. If the tubes dirty and drawing too much current
there is a lockout circuit on a15 that will not allow the CS oven and
2500
V to come up until the ion pump is below about 15-20ua on the meter. It
senses the current being drawn by the 3500 HV. Enters a15 on pin 1 and
inhibits the rest of the system.
If my thoughts are correct then you need to pump down the tube as Rodger
says with a 3500 V supply and as I suggested 300 ua is way more than
enough. There is a chance the tube may work in a relative quality sense.
That is it could lock but there are so few Cs that the output of the
system
is noisy.
Regards
Paul
WB8TSL
On Mon, Nov 14, 2022 at 3:00 PM 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
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@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
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
In general purpose transformers 60 Hz is fine but the HV transformer is KHz
as a heads up.
Paul
WB8TSL
On Mon, Nov 14, 2022 at 9:43 PM Lester Veenstra via time-nuts <
time-nuts@lists.febo.com> wrote:
Of course a small “Variac” on the primary will get the voltage to what
you want
Lester B Veenstra K1YCM MØYCM W8YCM 6Y6Y W8YCM/6Y 6Y8LV (Reformed
USNSG CTM1)
mailto:lester@veenstras.com lester@veenstras.com
452 Stable Ln
Keyser WV 26726 USA
GPS: 39.336826 N 78.982287 W (Google)
GPS: 39.33682 N 78.9823741 W (GPSDO)
Telephones:
Home: +1-304-289-6057
US cell +1-304-790-9192
Jamaica cell: +1-876-456-8898
From: Andy Talbot [mailto:andy.g4jnt@gmail.com]
Sent: Monday, November 14, 2022 3:44 PM
To: Lester Veenstra
Cc: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Re: 5061A HV Supply, et al. {External}
I've got three transformers going spare ... :-)
Andy G4JNT
IO90IV58AK12 (and others)
On Mon, 14 Nov 2022 at 20:40, Lester Veenstra m0ycm@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
Telephones:
Home: +1-304-289-6057
US cell +1-304-790-9192
Jamaica cell: +1-876-456-8898
-----Original Message-----
From: Andy Talbot via time-nuts [mailto:time-nuts@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@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
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
Not in my ovans. They run directly oiff od 50/60 Hz line. There is no RF freq flyback involved.
B>T>W> These would be useful with such a variac & transformer test supply.
https://www.ebay.com/vod/FetchOrderDetails?itemId=402568223370&transactionId=1108957800027&mkevt=1&mkpid=0&emsid=e11401.m1842.l5920&mkcid=7&ch=osgood&euid=78ef2d648c414a41a24157fcd09254de&bu=43198945816&exe=102809&ext=241959&osub=-1%7E1&crd=20221115061028&segname=11401 US Stock 4pcs CL01-12 Microwave Oven High Voltage Diode Rectifier
https://www.ebay.com/vod/FetchOrderDetails?itemId=402568223370&transactionId=1108957800027&mkevt=1&mkpid=0&emsid=e11401.m1842.l5919&mkcid=7&ch=osgood&euid=78ef2d648c414a41a24157fcd09254de&bu=43198945816&exe=102809&ext=241959&osub=-1%7E1&crd=20221115061028&segname=11401 US Stock 4pcs CL01-12 Microwave Oven High Voltage Diode Rectifier
Total: $7.47
Item ID: 402568223370
Lester B Veenstra K1YCM MØYCM W8YCM 6Y6Y W8YCM/6Y 6Y8LV (Reformed USNSG CTM1)
mailto:lester@veenstras.com lester@veenstras.com
452 Stable Ln
Keyser WV 26726 USA
GPS: 39.336826 N 78.982287 W (Google)
GPS: 39.33682 N 78.9823741 W (GPSDO)
Telephones:
Home: +1-304-289-6057
US cell +1-304-790-9192
Jamaica cell: +1-876-456-8898
From: paul swed [mailto:paulswedb@gmail.com]
Sent: Tuesday, November 15, 2022 8:37 AM
To: Discussion of precise time and frequency measurement
Cc: Andy Talbot; Lester Veenstra
Subject: Re: [time-nuts] Re: 5061A HV Supply, et al. {External}
In general purpose transformers 60 Hz is fine but the HV transformer is KHz as a heads up.
Paul
WB8TSL
On Mon, Nov 14, 2022 at 9:43 PM Lester Veenstra via time-nuts time-nuts@lists.febo.com wrote:
Of course a small “Variac” on the primary will get the voltage to what you want
Lester B Veenstra K1YCM MØYCM W8YCM 6Y6Y W8YCM/6Y 6Y8LV (Reformed USNSG CTM1)
mailto:lester@veenstras.com lester@veenstras.com
452 Stable Ln
Keyser WV 26726 USA
GPS: 39.336826 N 78.982287 W (Google)
GPS: 39.33682 N 78.9823741 W (GPSDO)
Telephones:
Home: +1-304-289-6057
US cell +1-304-790-9192
Jamaica cell: +1-876-456-8898
From: Andy Talbot [mailto:andy.g4jnt@gmail.com]
Sent: Monday, November 14, 2022 3:44 PM
To: Lester Veenstra
Cc: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Re: 5061A HV Supply, et al. {External}
I've got three transformers going spare ... :-)
Andy G4JNT
IO90IV58AK12 (and others)
On Mon, 14 Nov 2022 at 20:40, Lester Veenstra m0ycm@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
Telephones:
Home: +1-304-289-6057
US cell +1-304-790-9192
Jamaica cell: +1-876-456-8898
-----Original Message-----
From: Andy Talbot via time-nuts [mailto:time-nuts@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@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
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
