[volt-nuts] HP-3455A calibration
My new-to-me 3455A DVM (s/n 1622A06699) does not want to calibrate to the 10 Volt level although 1 Volt is fine. The 10V adjustment pot in the 11177B reference assembly simply doesn't adjust far enough—I can get the reading down to 10.00020 Volts but no lower. Just for the heck of it, I picked up another reference assembly from an eBay seller. It's an "A" assembly rather than the "B" the 3455 came with but it works fine and I am able to calibrate both 1V and 10V. The reference assemblies have a set of jumpers for "coarse adjust" so it should be possible to tweak the "B" version back into calibration. Does anyone have experience doing this? The service manual just says "return to the factory." It would be nice to hear from someone who has worked with these things before I start messing with the jumpers. Jeremy Sent from my iPad 4 ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Agilent 3458A Issues
Problem solved! As expected, operator error. When I did the CAL 0, I shorted the voltage and sense lines separately but did not short them together. This caused error 209, which caused the CAL 10V to fail since the zero was not done correctly. All is well now. Still learning. On Sat, Nov 18, 2017 at 12:58 PM, Randy Evans wrote: > When I try to execute a 10V cal, I get an error code "209 HARDWARE FAILURE > - - INTERNAL OVERLOAD:31" I suspect that the unit has a different > security code than 3458. I can't change it without opening up the unit, > which I don't want to do unless I decide to keep it. Do you have any other > suggestions on how to check the A9 card? > > On Sat, Nov 18, 2017 at 11:17 AM, Randy Evans > wrote: > >> Illya, >> >> That is a great idea. I will give it a try. >> >> Thanks >> >> On Sat, Nov 18, 2017 at 4:47 AM, Illya Tsemenko wrote: >> >>> Since you have 732A, testing should be easy enough. Calibrate faulty >>> meter for zero and DCV 10V to 732A, record CAL? 2,1 value. This is your LTZ >>> output. Then leave it running for few days to drift away and calibrate >>> again to same 732A. Check CAL? 2,1 again. Calculate the difference and if >>> it matches output drift (that 1.1ppm/day you mention) - you can be 80% sure >>> that A9 is a problem. Other 19% go to A1 and A3 circuits, as 7V is not used >>> directly in the meter, and there are still gain parts to get +12 and >>> -12VREF on A3 and 10Vish bipolar levels on A1. If your CAL? 2,1 stays same >>> (within 0.3ppm) then A9 is fine. >>> >>> >>> On November 18, 2017 12:59:53 PM GMT+08:00, Randy Evans < >>> randyevans2...@gmail.com> wrote: I just received an Agilent 3458A that has a problem with noise and a drifting voltage measurements. I am using two Fluke 732As to compare absolute voltage measurements over time against the Agilent and an HP 3458A. The HP unit has a new A3 ADC card and seems to be very stable and low noise, so is being used for comparison. I have been doing simultaneous absolute voltage measurements and DC Cal Constant measurements several times a day and then calculating the drift rates of the two units using the HP Service Note 18 procedure. The results indicate the Cal Constant drift rate of both units is very similar and within spec per Service Note 18. However, the absolute value measurements show the Agilent unit changing 1.1 ppm over a day whereas the HP unit is within a tenth of a ppm over a day. In my way of thinking the Cal Constant procedure assumes the voltage reference board in the 3458A is stable, hence the absolute value reading should remain essentially constant after each ACAL DCV, which is the case with the HP unit. Since the Agilent unit shows a steady drift in the absolute reading, this would indicate to me that the voltage reference board is likely the cause of the problem, and is also likely the cause of the noisy readings. If so, this is a “relatively” easy fix (I have several 3458A voltage reference boards, one of which has been continuously powered up for several years). The issue is that I have to make a decision to keep or return the Agilent. It has a cal seal on it and if I open the unit up to change the voltage reference board, I own it and can’t return it. I would appreciate an opinion from the members of the group as to what they think the odds are that the voltage reference board is the source of the problems with the Agilent 3458A. Thanks, Randy Evans >> > ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Agilent 3458A Issues
In message , Randy Evans writes: >When I try to execute a 10V cal, I get an error code "209 HARDWARE FAILURE >- - INTERNAL OVERLOAD:31" I suspect that the unit has a different security >code than 3458. The 3458 is quite elonquent, and will say so clearly if that is the problem. 209 means that the compiled in limit on one of all the many calibration values is out of range. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@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. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Agilent 3458A Issues
If you were able to run CAL 0 with the inputs shorted, then security is not an issue. After that, try CAL 10.xx whatever the value is. I think overload means the expected value is out of range. On Sat, Nov 18, 2017 at 3:58 PM, Randy Evans wrote: > When I try to execute a 10V cal, I get an error code "209 HARDWARE FAILURE > - - INTERNAL OVERLOAD:31" I suspect that the unit has a different security > code than 3458. I can't change it without opening up the unit, which I > don't want to do unless I decide to keep it. Do you have any other > suggestions on how to check the A9 card? > > On Sat, Nov 18, 2017 at 11:17 AM, Randy Evans > wrote: > > > Illya, > > > > That is a great idea. I will give it a try. > > > > Thanks > > > > On Sat, Nov 18, 2017 at 4:47 AM, Illya Tsemenko wrote: > > > >> Since you have 732A, testing should be easy enough. Calibrate faulty > >> meter for zero and DCV 10V to 732A, record CAL? 2,1 value. This is your > LTZ > >> output. Then leave it running for few days to drift away and calibrate > >> again to same 732A. Check CAL? 2,1 again. Calculate the difference and > if > >> it matches output drift (that 1.1ppm/day you mention) - you can be 80% > sure > >> that A9 is a problem. Other 19% go to A1 and A3 circuits, as 7V is not > used > >> directly in the meter, and there are still gain parts to get +12 and > >> -12VREF on A3 and 10Vish bipolar levels on A1. If your CAL? 2,1 stays > same > >> (within 0.3ppm) then A9 is fine. > >> > >> > >> On November 18, 2017 12:59:53 PM GMT+08:00, Randy Evans < > >> randyevans2...@gmail.com> wrote: > >>> > >>> I just received an Agilent 3458A that has a problem with noise and a > >>> drifting voltage measurements. I am using two Fluke 732As to compare > >>> absolute voltage measurements over time against the Agilent and an HP > >>> 3458A. The HP unit has a new A3 ADC card and seems to be very stable > and > >>> low noise, so is being used for comparison. I have been doing > simultaneous > >>> absolute voltage measurements and DC Cal Constant measurements several > >>> times a day and then calculating the drift rates of the two units > using the > >>> HP Service Note 18 procedure. > >>> > >>> > >>> > >>> The results indicate the Cal Constant drift rate of both units is very > >>> similar and within spec per Service Note 18. However, the absolute > value > >>> measurements show the Agilent unit changing 1.1 ppm over a day whereas > the > >>> HP unit is within a tenth of a ppm over a day. In my way of thinking > the > >>> Cal Constant procedure assumes the voltage reference board in the > 3458A is > >>> stable, hence the absolute value reading should remain essentially > constant > >>> after each ACAL DCV, which is the case with the HP unit. Since the > Agilent > >>> unit shows a steady drift in the absolute reading, this would indicate > to > >>> me that the voltage reference board is likely the cause of the > problem, and > >>> is also likely the cause of the noisy readings. If so, this is a > >>> “relatively” easy fix (I have several 3458A voltage reference boards, > one > >>> of which has been continuously powered up for several years). > >>> > >>> > >>> > >>> The issue is that I have to make a decision to keep or return the > Agilent. > >>> It has a cal seal on it and if I open the unit up to change the voltage > >>> reference board, I own it and can’t return it. I would appreciate an > >>> opinion from the members of the group as to what they think the odds > are > >>> that the voltage reference board is the source of the problems with the > >>> Agilent 3458A. > >>> > >>> > >>> > >>> Thanks, > >>> > >>> > >>> > >>> Randy Evans > >>> > >>> > > > ___ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/volt-nuts > and follow the instructions there. > ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Agilent 3458A Issues
When I try to execute a 10V cal, I get an error code "209 HARDWARE FAILURE - - INTERNAL OVERLOAD:31" I suspect that the unit has a different security code than 3458. I can't change it without opening up the unit, which I don't want to do unless I decide to keep it. Do you have any other suggestions on how to check the A9 card? On Sat, Nov 18, 2017 at 11:17 AM, Randy Evans wrote: > Illya, > > That is a great idea. I will give it a try. > > Thanks > > On Sat, Nov 18, 2017 at 4:47 AM, Illya Tsemenko wrote: > >> Since you have 732A, testing should be easy enough. Calibrate faulty >> meter for zero and DCV 10V to 732A, record CAL? 2,1 value. This is your LTZ >> output. Then leave it running for few days to drift away and calibrate >> again to same 732A. Check CAL? 2,1 again. Calculate the difference and if >> it matches output drift (that 1.1ppm/day you mention) - you can be 80% sure >> that A9 is a problem. Other 19% go to A1 and A3 circuits, as 7V is not used >> directly in the meter, and there are still gain parts to get +12 and >> -12VREF on A3 and 10Vish bipolar levels on A1. If your CAL? 2,1 stays same >> (within 0.3ppm) then A9 is fine. >> >> >> On November 18, 2017 12:59:53 PM GMT+08:00, Randy Evans < >> randyevans2...@gmail.com> wrote: >>> >>> I just received an Agilent 3458A that has a problem with noise and a >>> drifting voltage measurements. I am using two Fluke 732As to compare >>> absolute voltage measurements over time against the Agilent and an HP >>> 3458A. The HP unit has a new A3 ADC card and seems to be very stable and >>> low noise, so is being used for comparison. I have been doing simultaneous >>> absolute voltage measurements and DC Cal Constant measurements several >>> times a day and then calculating the drift rates of the two units using the >>> HP Service Note 18 procedure. >>> >>> >>> >>> The results indicate the Cal Constant drift rate of both units is very >>> similar and within spec per Service Note 18. However, the absolute value >>> measurements show the Agilent unit changing 1.1 ppm over a day whereas the >>> HP unit is within a tenth of a ppm over a day. In my way of thinking the >>> Cal Constant procedure assumes the voltage reference board in the 3458A is >>> stable, hence the absolute value reading should remain essentially constant >>> after each ACAL DCV, which is the case with the HP unit. Since the Agilent >>> unit shows a steady drift in the absolute reading, this would indicate to >>> me that the voltage reference board is likely the cause of the problem, and >>> is also likely the cause of the noisy readings. If so, this is a >>> “relatively” easy fix (I have several 3458A voltage reference boards, one >>> of which has been continuously powered up for several years). >>> >>> >>> >>> The issue is that I have to make a decision to keep or return the Agilent. >>> It has a cal seal on it and if I open the unit up to change the voltage >>> reference board, I own it and can’t return it. I would appreciate an >>> opinion from the members of the group as to what they think the odds are >>> that the voltage reference board is the source of the problems with the >>> Agilent 3458A. >>> >>> >>> >>> Thanks, >>> >>> >>> >>> Randy Evans >>> >>> > ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Agilent 3458A Issues
Illya, That is a great idea. I will give it a try. Thanks On Sat, Nov 18, 2017 at 4:47 AM, Illya Tsemenko wrote: > Since you have 732A, testing should be easy enough. Calibrate faulty meter > for zero and DCV 10V to 732A, record CAL? 2,1 value. This is your LTZ > output. Then leave it running for few days to drift away and calibrate > again to same 732A. Check CAL? 2,1 again. Calculate the difference and if > it matches output drift (that 1.1ppm/day you mention) - you can be 80% sure > that A9 is a problem. Other 19% go to A1 and A3 circuits, as 7V is not used > directly in the meter, and there are still gain parts to get +12 and > -12VREF on A3 and 10Vish bipolar levels on A1. If your CAL? 2,1 stays same > (within 0.3ppm) then A9 is fine. > > > On November 18, 2017 12:59:53 PM GMT+08:00, Randy Evans < > randyevans2...@gmail.com> wrote: >> >> I just received an Agilent 3458A that has a problem with noise and a >> drifting voltage measurements. I am using two Fluke 732As to compare >> absolute voltage measurements over time against the Agilent and an HP >> 3458A. The HP unit has a new A3 ADC card and seems to be very stable and >> low noise, so is being used for comparison. I have been doing simultaneous >> absolute voltage measurements and DC Cal Constant measurements several >> times a day and then calculating the drift rates of the two units using the >> HP Service Note 18 procedure. >> >> >> >> The results indicate the Cal Constant drift rate of both units is very >> similar and within spec per Service Note 18. However, the absolute value >> measurements show the Agilent unit changing 1.1 ppm over a day whereas the >> HP unit is within a tenth of a ppm over a day. In my way of thinking the >> Cal Constant procedure assumes the voltage reference board in the 3458A is >> stable, hence the absolute value reading should remain essentially constant >> after each ACAL DCV, which is the case with the HP unit. Since the Agilent >> unit shows a steady drift in the absolute reading, this would indicate to >> me that the voltage reference board is likely the cause of the problem, and >> is also likely the cause of the noisy readings. If so, this is a >> “relatively” easy fix (I have several 3458A voltage reference boards, one >> of which has been continuously powered up for several years). >> >> >> >> The issue is that I have to make a decision to keep or return the Agilent. >> It has a cal seal on it and if I open the unit up to change the voltage >> reference board, I own it and can’t return it. I would appreciate an >> opinion from the members of the group as to what they think the odds are >> that the voltage reference board is the source of the problems with the >> Agilent 3458A. >> >> >> >> Thanks, >> >> >> >> Randy Evans >> >> ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
[volt-nuts] Neon Bulbs NE-2
Jameco. Replace chopper NE-2s with great success from that sourceHank Sent from my Verizon 4G LTE Smartphone ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Neon bulbs for HP 3420B or 419A chopper
I'm in the process of getting some A2B neons from Mouser. Dave -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of Charles Steinmetz Sent: 18 November 2017 13:11 To: volt-nuts@febo.com Subject: Re: [volt-nuts] Neon bulbs for HP 3420B or 419A chopper David wrote: > Then an A3C (NE-2U) shouldn't work. The drive voltage is 125V. Correct. > The operating current is 1.5mA (.15V/102R) in the 3420B, so I would expect > this to be the A2B (NE-2V) part. The NE-2V is another 700uA design current lamp, just like the CML A2B and A2B-T. Indeed, if you look at p.117 of the 1965 GE glow lamp manual I linked to yesterday, you will see that it lists the NE-2V as an "A2B" lamp, with "NE-2V" in parentheses. So, the primary designation for this lamp was "A2B" at least as far back as the mid-'60s. Note that 700uA is the "design current," not the maximum safe current. GE explicitly sanctioned using neon glow lamps at up to 2x the design current, and they were routinely used at even higher currents back in the day. Some of GE's published application circuits used them at 2-3mA. Mostly, the design current was the current at which the lifetime was rated (higher current leads to shorter life). It seems easy enough for you to obtain CML A2B or A2B-T lamps from either Mouser or Digi-Key in the UK, so why don't you just get some and see how they work? > Interestingly the operating current for the 3420A is 2.45mA which you would > think might suggest the A3C (NE-2U), but the drive voltage isn't high enough! I would not be surprised to find that the original neon lamps in the 3420A were 700uA "design current" parts that HP determined had sufficient lifetime at the 3420A operating current. If this is correct, presumably the 3420A choppers fail with lower operating hours than the 419 and 3420B choppers. (Perhaps this is why HP reduced the neon currents in the "B" version?) Note that 700uA was the highest "design current" rating for wire-leaded, standard-brightness neons back in the day. In a related vein, neon glow lamps produce less light as they age (both from envelope darkening and because less of the cathode [DC operation] is illuminated). This may mean that the HP optical choppers degrade significantly before they outright fail, so the chopper amps may start drifting more than specified some time before the choppers fail entirely. Best regards, Charles ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Neon bulbs for HP 3420B or 419A chopper
David wrote: Then an A3C (NE-2U) shouldn't work. The drive voltage is 125V. Correct. The operating current is 1.5mA (.15V/102R) in the 3420B, so I would expect this to be the A2B (NE-2V) part. The NE-2V is another 700uA design current lamp, just like the CML A2B and A2B-T. Indeed, if you look at p.117 of the 1965 GE glow lamp manual I linked to yesterday, you will see that it lists the NE-2V as an "A2B" lamp, with "NE-2V" in parentheses. So, the primary designation for this lamp was "A2B" at least as far back as the mid-'60s. Note that 700uA is the "design current," not the maximum safe current. GE explicitly sanctioned using neon glow lamps at up to 2x the design current, and they were routinely used at even higher currents back in the day. Some of GE's published application circuits used them at 2-3mA. Mostly, the design current was the current at which the lifetime was rated (higher current leads to shorter life). It seems easy enough for you to obtain CML A2B or A2B-T lamps from either Mouser or Digi-Key in the UK, so why don't you just get some and see how they work? Interestingly the operating current for the 3420A is 2.45mA which you would think might suggest the A3C (NE-2U), but the drive voltage isn't high enough! I would not be surprised to find that the original neon lamps in the 3420A were 700uA "design current" parts that HP determined had sufficient lifetime at the 3420A operating current. If this is correct, presumably the 3420A choppers fail with lower operating hours than the 419 and 3420B choppers. (Perhaps this is why HP reduced the neon currents in the "B" version?) Note that 700uA was the highest "design current" rating for wire-leaded, standard-brightness neons back in the day. In a related vein, neon glow lamps produce less light as they age (both from envelope darkening and because less of the cathode [DC operation] is illuminated). This may mean that the HP optical choppers degrade significantly before they outright fail, so the chopper amps may start drifting more than specified some time before the choppers fail entirely. Best regards, Charles ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Agilent 3458A Issues
Since you have 732A, testing should be easy enough. Calibrate faulty meter for zero and DCV 10V to 732A, record CAL? 2,1 value. This is your LTZ output. Then leave it running for few days to drift away and calibrate again to same 732A. Check CAL? 2,1 again. Calculate the difference and if it matches output drift (that 1.1ppm/day you mention) - you can be 80% sure that A9 is a problem. Other 19% go to A1 and A3 circuits, as 7V is not used directly in the meter, and there are still gain parts to get +12 and -12VREF on A3 and 10Vish bipolar levels on A1. If your CAL? 2,1 stays same (within 0.3ppm) then A9 is fine. On November 18, 2017 12:59:53 PM GMT+08:00, Randy Evans wrote: >I just received an Agilent 3458A that has a problem with noise and a >drifting voltage measurements. I am using two Fluke 732As to compare >absolute voltage measurements over time against the Agilent and an HP >3458A. The HP unit has a new A3 ADC card and seems to be very stable >and >low noise, so is being used for comparison. I have been doing >simultaneous >absolute voltage measurements and DC Cal Constant measurements several >times a day and then calculating the drift rates of the two units using >the >HP Service Note 18 procedure. > > > >The results indicate the Cal Constant drift rate of both units is very >similar and within spec per Service Note 18. However, the absolute >value >measurements show the Agilent unit changing 1.1 ppm over a day whereas >the >HP unit is within a tenth of a ppm over a day. In my way of thinking >the >Cal Constant procedure assumes the voltage reference board in the 3458A >is >stable, hence the absolute value reading should remain essentially >constant >after each ACAL DCV, which is the case with the HP unit. Since the >Agilent >unit shows a steady drift in the absolute reading, this would indicate >to >me that the voltage reference board is likely the cause of the problem, >and >is also likely the cause of the noisy readings. If so, this is a >“relatively” easy fix (I have several 3458A voltage reference boards, >one >of which has been continuously powered up for several years). > > > >The issue is that I have to make a decision to keep or return the >Agilent. >It has a cal seal on it and if I open the unit up to change the voltage >reference board, I own it and can’t return it. I would appreciate an >opinion from the members of the group as to what they think the odds >are >that the voltage reference board is the source of the problems with the >Agilent 3458A. > > > >Thanks, > > > >Randy Evans ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Neon bulbs for HP 3420B or 419A chopper
Then an A3C (NE-2U) shouldn't work. The drive voltage is 125V. The operating current is 1.5mA (.15V/102R) in the 3420B, so I would expect this to be the A2B (NE-2V) part. Interestingly the operating current for the 3420A is 2.45mA which you would think might suggest the A3C (NE-2U), but the drive voltage isn't high enough! Dave -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of Charles Steinmetz Sent: 17 November 2017 20:53 To: volt-nuts@febo.com Subject: Re: [volt-nuts] Neon bulbs for HP 3420B or 419A chopper george wrote: > Farnell (UK) list NE-2U neon lamps. Note that the NE-2U is a "high brightness" lamp with a 135vDC (max) strike voltage. Standard brightness lamps strike at 90vDC (max). The Farnell site available to me here in the US lists the CML (Chicago Miniature Lamp) A3C, which CML list with NE-2U as the "Old Reference Number." Farnell do not seem to carry the CML standard brightness lamps with reduced dark effect. According to the CML datasheet, there are four part numbers with that combination: A1D, A1D-T, A2B, and A2B-T. "T" indicates tinned leads. The design current of the A1 parts is 300uA, and of the A2 parts it is 700uA. Check the schematic and you should be able to calculate the neon operating current of the circuit, and choose A1 or A2 accordingly. Dave, perhaps Farnell will special order one of these part numbers for you. If Farnell can't get you the right part, I believe both Mouser and Digi-Key operate in the UK and both have A1D(-T) and A2B(-T) parts in stock (in the UK, I think). Cheers, Charles ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
Re: [volt-nuts] Neon bulbs for HP 3420B or 419A chopper
I just searched for ne-2u on uk.farnell.com and came up dry. could you point me to the right page please? Dave -Original Message- From: volt-nuts [mailto:volt-nuts-boun...@febo.com] On Behalf Of george Sent: 17 November 2017 16:37 To: volt-nuts@febo.com Subject: Re: [volt-nuts] Neon bulbs for HP 3420B or 419A chopper Hi Dave Farnell (UK) list NE-2U neon lamps. 73 George G6HIG ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there. ___ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.
