Re: [time-nuts] HP and other equipment failure
audiophile outlets You've got to be kidding but not even. At least, nobody is forcing anybody to buy them... Didier Peter Gottlieb n...@verizon.net wrote: The current distortion from simple transformer-rectifier-capacitor power supplies contains a lot of third harmonic content. In a 3 phase system (as are all distribution systems for commercial and industrial) the third harmonic ADDS in the neutral, or creates circulating currents in a delta configuration. These currents, as you mention, can get very large and were the cause of many transformer explosions in cities as these power supplies became common. The transformer designs had to be improved, but the PFC supplies make a big difference. How many of you have looked at the power line waveform, especially in an industrial or commercial area? Doesn't look much like a sine wave, does it? So it's pretty funny to see audiophile outlets (http://www.dedicatedaudio.com/power_outlets). Peter On 6/15/2013 6:56 PM, stan, W1LE wrote: PFC to me is power factor correction, not only the classical power factor to minimize (VAR) volt-amp reactive component, but also to remove the harmonic load current imposd on the electrical power system. A '90's onward technique. in th 80's and 90's without the harmonic load current reduction and having a few 100 end items of equipment, each withtheir own a switch mode power supplly, it was not uncommon to find hundreds of amps of the third harmonc on neutra, in the electrical power distribution system. Could be a serious EMC problem if you were dealing with voice grade channels. And people safety issues. Stan, W1LE Cape Cod On 15-Jun-13 5:52 PM, J. L. Trantham wrote: Sorry for the interruption but what is 'PFC'? Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Saturday, June 15, 2013 4:09 PM To: Robert Atkinson; Discussion of precise time and frequency measurement Cc: Perry Sandeen Subject: Re: [time-nuts] HP and other equipment failure In message 1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com, Robert Atkinson writes: While I agree with everything else you say, you CAN have too much filter capacitance. At least where dc rectifier / filter (smoothing) circuits are concerned. Increasing C causes increased ripple current [...] And ripple current can be a major source of power-line frequency noise in all electronics. The main reason why switchmode power-supplies today (can) outperform linear power supplies with respect to noise, is because the legally mandated PFC correction eliminates the bridge-rectifier ripple harmonics. I would not hessitate to use a good quality switchmode to replace the linear supply in a HP5370B. I did some experiments a couple of years ago, with an audio-amplifier: I put a standard PFC corrector chip on the secondary side of the trafo. The overall result was not satisfactory, but the 50 Hz sneer we all know and hate was absent, and the Tzoing! power-on mechanical shock from the trafo was also eliminated, as was the consequent dimming of the lights ;-) The main reason not to do this, is that you need some physically gargantuan coils for a 10A+ PFC-switcher. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1432 / Virus Database: 3199/5913 - Release Date: 06/15/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Sent from my Motorola Droid Razr 4G LTE wireless tracker while I do other things. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
The current distortion from simple transformer-rectifier-capacitor power supplies contains a lot of third harmonic content. In a 3 phase system (as are all distribution systems for commercial and industrial) the third harmonic ADDS in the neutral, or creates circulating currents in a delta configuration. These currents, as you mention, can get very large and were the cause of many transformer explosions in cities as these power supplies became common. The transformer designs had to be improved, but the PFC supplies make a big difference. How many of you have looked at the power line waveform, especially in an industrial or commercial area? Doesn't look much like a sine wave, does it? So it's pretty funny to see audiophile outlets (http://www.dedicatedaudio.com/power_outlets). Peter On 6/15/2013 6:56 PM, stan, W1LE wrote: PFC to me is power factor correction, not only the classical power factor to minimize (VAR) volt-amp reactive component, but also to remove the harmonic load current imposd on the electrical power system. A '90's onward technique. in th 80's and 90's without the harmonic load current reduction and having a few 100 end items of equipment, each withtheir own a switch mode power supplly, it was not uncommon to find hundreds of amps of the third harmonc on neutra, in the electrical power distribution system. Could be a serious EMC problem if you were dealing with voice grade channels. And people safety issues. Stan, W1LE Cape Cod On 15-Jun-13 5:52 PM, J. L. Trantham wrote: Sorry for the interruption but what is 'PFC'? Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Saturday, June 15, 2013 4:09 PM To: Robert Atkinson; Discussion of precise time and frequency measurement Cc: Perry Sandeen Subject: Re: [time-nuts] HP and other equipment failure In message 1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com, Robert Atkinson writes: While I agree with everything else you say, you CAN have too much filter capacitance. At least where dc rectifier / filter (smoothing) circuits are concerned. Increasing C causes increased ripple current [...] And ripple current can be a major source of power-line frequency noise in all electronics. The main reason why switchmode power-supplies today (can) outperform linear power supplies with respect to noise, is because the legally mandated PFC correction eliminates the bridge-rectifier ripple harmonics. I would not hessitate to use a good quality switchmode to replace the linear supply in a HP5370B. I did some experiments a couple of years ago, with an audio-amplifier: I put a standard PFC corrector chip on the secondary side of the trafo. The overall result was not satisfactory, but the 50 Hz sneer we all know and hate was absent, and the Tzoing! power-on mechanical shock from the trafo was also eliminated, as was the consequent dimming of the lights ;-) The main reason not to do this, is that you need some physically gargantuan coils for a 10A+ PFC-switcher. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1432 / Virus Database: 3199/5913 - Release Date: 06/15/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
On 6/17/13 5:33 AM, Peter Gottlieb wrote: The current distortion from simple transformer-rectifier-capacitor power supplies contains a lot of third harmonic content. In a 3 phase system (as are all distribution systems for commercial and industrial) the third harmonic ADDS in the neutral, or creates circulating currents in a delta configuration. These currents, as you mention, can get very large and were the cause of many transformer explosions in cities as these power supplies became common. The transformer designs had to be improved, but the PFC supplies make a big difference. How many of you have looked at the power line waveform, especially in an industrial or commercial area? Doesn't look much like a sine wave, does it? So it's pretty funny to see audiophile outlets (http://www.dedicatedaudio.com/power_outlets). Peter The PFC correction stuff is, as you say, more about harmonic content reduction than actual power factor. The rules on the current waveform came in as part and parcel of the power factor rules, so maybe it was just a simpler way to explain it? It's all about looking more like a resistive load. The US National Electrical Code was updated about 15-20 years ago because of the neutral current problem. In light industrial, office, running 208/120Y is very common, the old codes allowed the neutral to be smaller than the phase conductors (assuming that the loads would be resistive and all balance out) but with all those capacitive input filters, the current in the neutral got pretty high and there were fears of fires and overheating (I don't know if there were actually any fires, but poor voltage stability and heating of distribution hardware is probably more likely). Certainly, the utilities weren't wild about the harmonic currents, so they almost certainly agitated for the change as well. (Imagine you're a utility servicing a multitenant building, but the tenants all have single phase service, which the utility spreads around the three phases. The utility has the problem of the distribution transformers and the triplex currents. And, in fact, this harmonic thing is hard to fix in distribution equipment anyway (some set of tuned traps?) so it does make sense to push it to the user. The issue also arises with fluorescent and other gas discharge lighting, particularly with electronic ballasts (e.g. switchers). The old magnetic ballasts (basically just a big inductor) sort of inherently act as a low pass filter, and solve the harmonic problem by getting warm. And, they'd have a very lagging power factor, but a fairly fixed on that you could compensate with capacitor banks. As folks transitioned to the newer ballasts, the non-sinusoidal current problem probably got worse. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
Something else has gotten much worse with switchers- RFI. While most of them are supposed to be approved in some way, about 80% of them generate unacceptable levels of RF interference. So do the supplies for the under the counter LV lamps and LED drivers. How was the 80% figure arrived at? Bought 10 supplies and tested across the 1.8 -30 MHz range by looking at pan adapter output attached to my ham radio. 8/10 produced unacceptable noise levels. Then there is the worst of all-- most plasma display TV's. They can wipe out blocks with their noise. Then there are the treadmills, high efficiency air conditoners and now washing machines. Anything with a variable speed DC motor... Regards, Brian On 6/17/2013 13:56, Jim Lux wrote: On 6/17/13 5:33 AM, Peter Gottlieb wrote: The current distortion from simple transformer-rectifier-capacitor power supplies contains a lot of third harmonic content. In a 3 phase system (as are all distribution systems for commercial and industrial) the third harmonic ADDS in the neutral, or creates circulating currents in a delta configuration. These currents, as you mention, can get very large and were the cause of many transformer explosions in cities as these power supplies became common. The transformer designs had to be improved, but the PFC supplies make a big difference. How many of you have looked at the power line waveform, especially in an industrial or commercial area? Doesn't look much like a sine wave, does it? So it's pretty funny to see audiophile outlets (http://www.dedicatedaudio.com/power_outlets). Peter The PFC correction stuff is, as you say, more about harmonic content reduction than actual power factor. The rules on the current waveform came in as part and parcel of the power factor rules, so maybe it was just a simpler way to explain it? It's all about looking more like a resistive load. The US National Electrical Code was updated about 15-20 years ago because of the neutral current problem. In light industrial, office, running 208/120Y is very common, the old codes allowed the neutral to be smaller than the phase conductors (assuming that the loads would be resistive and all balance out) but with all those capacitive input filters, the current in the neutral got pretty high and there were fears of fires and overheating (I don't know if there were actually any fires, but poor voltage stability and heating of distribution hardware is probably more likely). Certainly, the utilities weren't wild about the harmonic currents, so they almost certainly agitated for the change as well. (Imagine you're a utility servicing a multitenant building, but the tenants all have single phase service, which the utility spreads around the three phases. The utility has the problem of the distribution transformers and the triplex currents. And, in fact, this harmonic thing is hard to fix in distribution equipment anyway (some set of tuned traps?) so it does make sense to push it to the user. The issue also arises with fluorescent and other gas discharge lighting, particularly with electronic ballasts (e.g. switchers). The old magnetic ballasts (basically just a big inductor) sort of inherently act as a low pass filter, and solve the harmonic problem by getting warm. And, they'd have a very lagging power factor, but a fairly fixed on that you could compensate with capacitor banks. As folks transitioned to the newer ballasts, the non-sinusoidal current problem probably got worse. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5917 - Release Date: 06/16/13 - No virus found in this message. Checked by AVG - www.avg.com Version: 2012.0.2242 / Virus Database: 3199/5917 - Release Date: 06/16/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
An Audiophool and his money are soon parted. -John === The current distortion from simple transformer-rectifier-capacitor power supplies contains a lot of third harmonic content. In a 3 phase system (as are all distribution systems for commercial and industrial) the third harmonic ADDS in the neutral, or creates circulating currents in a delta configuration. These currents, as you mention, can get very large and were the cause of many transformer explosions in cities as these power supplies became common. The transformer designs had to be improved, but the PFC supplies make a big difference. How many of you have looked at the power line waveform, especially in an industrial or commercial area? Doesn't look much like a sine wave, does it? So it's pretty funny to see audiophile outlets (http://www.dedicatedaudio.com/power_outlets). Peter On 6/15/2013 6:56 PM, stan, W1LE wrote: PFC to me is power factor correction, not only the classical power factor to minimize (VAR) volt-amp reactive component, but also to remove the harmonic load current imposd on the electrical power system. A '90's onward technique. in th 80's and 90's without the harmonic load current reduction and having a few 100 end items of equipment, each withtheir own a switch mode power supplly, it was not uncommon to find hundreds of amps of the third harmonc on neutra, in the electrical power distribution system. Could be a serious EMC problem if you were dealing with voice grade channels. And people safety issues. Stan, W1LE Cape Cod On 15-Jun-13 5:52 PM, J. L. Trantham wrote: Sorry for the interruption but what is 'PFC'? Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Saturday, June 15, 2013 4:09 PM To: Robert Atkinson; Discussion of precise time and frequency measurement Cc: Perry Sandeen Subject: Re: [time-nuts] HP and other equipment failure In message 1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com, Robert Atkinson writes: While I agree with everything else you say, you CAN have too much filter capacitance. At least where dc rectifier / filter (smoothing) circuits are concerned. Increasing C causes increased ripple current [...] And ripple current can be a major source of power-line frequency noise in all electronics. The main reason why switchmode power-supplies today (can) outperform linear power supplies with respect to noise, is because the legally mandated PFC correction eliminates the bridge-rectifier ripple harmonics. I would not hessitate to use a good quality switchmode to replace the linear supply in a HP5370B. I did some experiments a couple of years ago, with an audio-amplifier: I put a standard PFC corrector chip on the secondary side of the trafo. The overall result was not satisfactory, but the 50 Hz sneer we all know and hate was absent, and the Tzoing! power-on mechanical shock from the trafo was also eliminated, as was the consequent dimming of the lights ;-) The main reason not to do this, is that you need some physically gargantuan coils for a 10A+ PFC-switcher. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1432 / Virus Database: 3199/5913 - Release Date: 06/15/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
That's criminal! Tom - Original Message - From: J. Forster j...@quikus.com To: n...@verizon.net; Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Monday, June 17, 2013 12:43 PM Subject: Re: [time-nuts] HP and other equipment failure An Audiophool and his money are soon parted. -John === The current distortion from simple transformer-rectifier-capacitor power supplies contains a lot of third harmonic content. In a 3 phase system (as are all distribution systems for commercial and industrial) the third harmonic ADDS in the neutral, or creates circulating currents in a delta configuration. These currents, as you mention, can get very large and were the cause of many transformer explosions in cities as these power supplies became common. The transformer designs had to be improved, but the PFC supplies make a big difference. How many of you have looked at the power line waveform, especially in an industrial or commercial area? Doesn't look much like a sine wave, does it? So it's pretty funny to see audiophile outlets (http://www.dedicatedaudio.com/power_outlets). Peter On 6/15/2013 6:56 PM, stan, W1LE wrote: PFC to me is power factor correction, not only the classical power factor to minimize (VAR) volt-amp reactive component, but also to remove the harmonic load current imposd on the electrical power system. A '90's onward technique. in th 80's and 90's without the harmonic load current reduction and having a few 100 end items of equipment, each withtheir own a switch mode power supplly, it was not uncommon to find hundreds of amps of the third harmonc on neutra, in the electrical power distribution system. Could be a serious EMC problem if you were dealing with voice grade channels. And people safety issues. Stan, W1LE Cape Cod On 15-Jun-13 5:52 PM, J. L. Trantham wrote: Sorry for the interruption but what is 'PFC'? Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Saturday, June 15, 2013 4:09 PM To: Robert Atkinson; Discussion of precise time and frequency measurement Cc: Perry Sandeen Subject: Re: [time-nuts] HP and other equipment failure In message 1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com, Robert Atkinson writes: While I agree with everything else you say, you CAN have too much filter capacitance. At least where dc rectifier / filter (smoothing) circuits are concerned. Increasing C causes increased ripple current [...] And ripple current can be a major source of power-line frequency noise in all electronics. The main reason why switchmode power-supplies today (can) outperform linear power supplies with respect to noise, is because the legally mandated PFC correction eliminates the bridge-rectifier ripple harmonics. I would not hessitate to use a good quality switchmode to replace the linear supply in a HP5370B. I did some experiments a couple of years ago, with an audio-amplifier: I put a standard PFC corrector chip on the secondary side of the trafo. The overall result was not satisfactory, but the 50 Hz sneer we all know and hate was absent, and the Tzoing! power-on mechanical shock from the trafo was also eliminated, as was the consequent dimming of the lights ;-) The main reason not to do this, is that you need some physically gargantuan coils for a 10A+ PFC-switcher. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1432 / Virus Database: 3199/5913 - Release Date: 06/15/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
In message 51bf15a8.40...@earthlink.net, Jim Lux writes: The issue also arises with fluorescent [...] As folks transitioned to the newer ballasts, the non-sinusoidal current problem probably got worse. I don't know about US, but in EU they must have PFC correction, and the ones I've seen do, because the PFC circuit makes for a neat way to ignite the tube first time. PS: The fact that you get about 10-20% more light (due to the high frequency drive) and longer lifetime (no burnouts) are good reasons to upgrade. Here in .dk it's often cheaper to buy a new armature with tube, than a spare tube... -- 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
I don't know what's more incredible, that people sell that stuff or that people buy it. Regards. Max. K 4 O DS. Email: m...@maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Woodworking site http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html Music site: http://www.maxsmusicplace.com To subscribe to the fun with transistors group send an email to. funwithtransistors-subscr...@yahoogroups.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscr...@yahoogroups.com To subscribe to the fun with wood group send a blank email to funwithwood-subscr...@yahoogroups.com - Original Message - From: Peter Gottlieb n...@verizon.net To: time-nuts@febo.com Sent: Monday, June 17, 2013 7:33 AM Subject: Re: [time-nuts] HP and other equipment failure The current distortion from simple transformer-rectifier-capacitor power supplies contains a lot of third harmonic content. In a 3 phase system (as are all distribution systems for commercial and industrial) the third harmonic ADDS in the neutral, or creates circulating currents in a delta configuration. These currents, as you mention, can get very large and were the cause of many transformer explosions in cities as these power supplies became common. The transformer designs had to be improved, but the PFC supplies make a big difference. How many of you have looked at the power line waveform, especially in an industrial or commercial area? Doesn't look much like a sine wave, does it? So it's pretty funny to see audiophile outlets (http://www.dedicatedaudio.com/power_outlets). Peter On 6/15/2013 6:56 PM, stan, W1LE wrote: PFC to me is power factor correction, not only the classical power factor to minimize (VAR) volt-amp reactive component, but also to remove the harmonic load current imposd on the electrical power system. A '90's onward technique. in th 80's and 90's without the harmonic load current reduction and having a few 100 end items of equipment, each withtheir own a switch mode power supplly, it was not uncommon to find hundreds of amps of the third harmonc on neutra, in the electrical power distribution system. Could be a serious EMC problem if you were dealing with voice grade channels. And people safety issues. Stan, W1LE Cape Cod On 15-Jun-13 5:52 PM, J. L. Trantham wrote: Sorry for the interruption but what is 'PFC'? Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Saturday, June 15, 2013 4:09 PM To: Robert Atkinson; Discussion of precise time and frequency measurement Cc: Perry Sandeen Subject: Re: [time-nuts] HP and other equipment failure In message 1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com, Robert Atkinson writes: While I agree with everything else you say, you CAN have too much filter capacitance. At least where dc rectifier / filter (smoothing) circuits are concerned. Increasing C causes increased ripple current [...] And ripple current can be a major source of power-line frequency noise in all electronics. The main reason why switchmode power-supplies today (can) outperform linear power supplies with respect to noise, is because the legally mandated PFC correction eliminates the bridge-rectifier ripple harmonics. I would not hessitate to use a good quality switchmode to replace the linear supply in a HP5370B. I did some experiments a couple of years ago, with an audio-amplifier: I put a standard PFC corrector chip on the secondary side of the trafo. The overall result was not satisfactory, but the 50 Hz sneer we all know and hate was absent, and the Tzoing! power-on mechanical shock from the trafo was also eliminated, as was the consequent dimming of the lights ;-) The main reason not to do this, is that you need some physically gargantuan coils for a 10A+ PFC-switcher. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1432 / Virus Database: 3199/5913 - Release Date: 06/15/13 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
On 6/17/13 10:39 AM, Poul-Henning Kamp wrote: In message 51bf15a8.40...@earthlink.net, Jim Lux writes: The issue also arises with fluorescent [...] As folks transitioned to the newer ballasts, the non-sinusoidal current problem probably got worse. I don't know about US, but in EU they must have PFC correction, and the ones I've seen do, because the PFC circuit makes for a neat way to ignite the tube first time. They do now, in the US, but I'll bet the first ones on the market did not. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
In the classical (transformer -) [bridge] rectifier - storage capacitor configuration, the capacitor charge current is creating short high peaks on the current waveform (and therefor truncate the peaks of the voltage waveform, the distribution circuit resistance being finite), due to the nonlinear load. The negative effects are much more due to high current harmonics than (slightly) capacitive cos fi, and increase the losses in the distribution circuits. On 6/16/2013 12:57 AM, Azelio Boriani wrote: Although off-topic here, the PFC (or power factor correction) is a switching mode front-end used to correct the cos-phi of the otherwise capacitive load that every switching mode power supply is for the mains. On Sat, Jun 15, 2013 at 11:52 PM, J. L. Tranthamjlt...@att.net wrote: Sorry for the interruption but what is 'PFC'? Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Saturday, June 15, 2013 4:09 PM To: Robert Atkinson; Discussion of precise time and frequency measurement Cc: Perry Sandeen Subject: Re: [time-nuts] HP and other equipment failure In message1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com, Robert Atkinson writes: While I agree with everything else you say, you CAN have too much filter capacitance. At least where dc rectifier / filter (smoothing) circuits are concerned. Increasing C causes increased ripple current [...] And ripple current can be a major source of power-line frequency noise in all electronics. The main reason why switchmode power-supplies today (can) outperform linear power supplies with respect to noise, is because the legally mandated PFC correction eliminates the bridge-rectifier ripple harmonics. I would not hessitate to use a good quality switchmode to replace the linear supply in a HP5370B. I did some experiments a couple of years ago, with an audio-amplifier: I put a standard PFC corrector chip on the secondary side of the trafo. The overall result was not satisfactory, but the 50 Hz sneer we all know and hate was absent, and the Tzoing! power-on mechanical shock from the trafo was also eliminated, as was the consequent dimming of the lights ;-) The main reason not to do this, is that you need some physically gargantuan coils for a 10A+ PFC-switcher. -- 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure - availability
On 16 June 2013 01:33, k...@aol.com wrote: Greetings Gentlemen! I have been following the thread on HP equipment repair, as I have a bunch of it and am waiting the inevitable day when something starts to smoke. That being said, I agree with the gentlemen that say fixing is better than junking and also about the diminishing supply. I don't know if you look at the yahoo group testequiptra...@yahoogroups.com, but someone on there is selling quite a bit of HP kit. Most is RF (noise figure related, VNAs etc), not directly timing related, thogh some might be of interest to time nuts. This year at the Dayton Hamvention, a friend of mine, who is a fairly large surplus equipment dealer, did not sell. Instead he came only to buy: All older HP gear. He ran around the Fest buying every 3586, old logic analyzer, even an 8510 Network analyzer, all to strip out the boards with the gold plated lands. I've never seen an 8510 VNA, but I see some comment from Dr. Joel Dunsmore (Dr_Joel) on the Agilent forum that made me think. Apparentlly to get the same performance from Agilent's top end PNA-X series of VNAs as is available on a top end 8510 system, you have to order a metrology option on the PNA-X. Obviously the modern units do more, and are faster, but it seems for S parameters, a top-end 8510 system is hard to beat. The guy on testequiptra...@yahoogroups.com has several 8510 systems, though I have no idea if they are bottom or top end. I've got an obsolete, but not too old (late 1990's) 8720D (20 GHz) VNA. It is not as capable as an 8510, but I can pick it up with one hand and it does not give me a hernia. He had numbers for gold yield for each item, so much per pound of board etc. Now whether you agree about the return on gold scrap doesn't matter. The thing is, he is making a dent in the number of pieces available on the market. Stuff will get rarer. It is a real shame this kit goes for scrap. I don't see any way to stop it though. It's a bit like steam engines in England. Thousands of trains were scrapped, but now those few that have been restored a worth a smal fortune. I was watching a TV program once, where this guy who had restored a train was being interviewed. Apparently him and his friends approached a scrap dealer and asked what he wanted for one of the trains in his scrap yard. The dealer asked what he wanted to do with it, so they replied they wanted to restore it. With that the scrap dealer told them they could have it, as long as it was not scrapped! Nothing lasts forever, which is why I pile stuff up for my own use. As to surplus, I like to say I was at the party when the booze ran out 73, Jeff Kruth WA3ZKR I knew someone who bought whisky as an investment. Perhaps it will be test equipment next! I paid $16000 for my 8720D VNA about a year ago, and I expect that will depreciate as it is not that old. But the older kit will probaby not depreciate any more. It has probably hit rock bottom. Prices in the UK are much higher than in the US. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
Hi Perry, I was browsing a 1988 HP catalogue tonight.. The 8566B came in at a cool 62 thousand dollars new. Wow! -marki -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Perry Sandeen Sent: Friday, 14 June 2013 2:48 PM To: time-nuts@febo.com Subject: [time-nuts] HP and other equipment failure All, There has been an on and off discussion of equipment failure so I’d thought I’d add my experience. First I’ve been repairing HP equipment since 1976 before many of you were born. I now have over 16 pieces of HP test equipment and several units now need repair. In my experience, the vast amount of failures are electrolytic caps with some aggravated by heat. Someone floated the notion of not repairing HP equipment but cannibalizing it for parts. Please bear with me on my long story. After WWII there were all sorts of surplus stores selling everything in the mid-fifties. I even remember an add in popular Mechanics magazine for a Norden bombsite for $29.95. Much of my allowance was spent on mysterious wonders like a IFF receiver. Hams reveled in B-29 prop pitch motors for rotating beam antennas. Since it was 28 volt stuff it was far, far cheaper than commercial equivalents. Then it all gradually disappeared. Now people want $75 or more for a cruddy ARC-5 receiver. Now this is how it applies to us today. If one peruses the Ebay adds for HP test equipment one frequently sees a statement like *removed from a place that went out of business* or something similar. True, the equipment we are buying is 20 years old or older. But it is going away never to return. I saw an old Ebay invoice from 12 years ago where I won a working HP 3586B for $50. The shipping cost me more! Now a non-functional unit sells for $400. These prices are only going to continue to rise as the supply continues to diminish. But this equipment is repairable unlike the questionable test equipment from China. Doing preventative maintenance on this equipment is not optional if you want it to continue working. All electrolytic caps should be replaced, except for tantalums. That will be more on a case by case business. This is equipment you can repair. This is not very true for the newer stuff. On the HP 3586B for example, there are a dozen or so of TVA atoms. When I do mine I expect it will then lock below 500 KHz as it is specified. The HP 5370B needs far more cooling than provided. I have even given thought to adding additional resistances to the pass transistor collectors on the outside by the heat sink. I found on my two that the mother board was scorched from overheating by rectifier diodes. This will have to wait until after we have moved. I will also add EFC to the 10811 oscillator. (Why that feature was omitted can be answered by Ric). There are two long standing truths about electronic equipment. One you can’t have too much filter capacitance. Two, you can’t cool too much. (Please spare me the liquid nitrogen or submarine battery comments.) Regards, Perrier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
Hi Perry, While I agree with everything else you say, you CAN have too much filter capacitance. At least where dc rectifier / filter (smoothing) circuits are concerned. Increasing C causes increased ripple current and inrush current and can overstress rectifiers and transformers. Not actually a problem in most cases, but if the rectifier or transformer is already marginal, blindly slapping in a much (2x) larger capacitor can cause troubles. Robert G8RPI. From: Perry Sandeen sandee...@yahoo.com To: time-nuts@febo.com time-nuts@febo.com Sent: Friday, 14 June 2013, 5:48 Subject: [time-nuts] HP and other equipment failure All, There has been an on and off discussion of equipment failure so I’d thought I’d add my experience. First I’ve been repairing HP equipment since 1976 before many of you were born. I now have over 16 pieces of HP test equipment and several units now need repair. In my experience, the vast amount of failures are electrolytic caps with some aggravated by heat. Someone floated the notion of not repairing HP equipment but cannibalizing it for parts. Please bear with me on my long story. After WWII there were all sorts of surplus stores selling everything in the mid-fifties. I even remember an add in popular Mechanics magazine for a Norden bombsite for $29.95. Much of my allowance was spent on mysterious wonders like a IFF receiver. Hams reveled in B-29 prop pitch motors for rotating beam antennas. Since it was 28 volt stuff it was far, far cheaper than commercial equivalents. Then it all gradually disappeared. Now people want $75 or more for a cruddy ARC-5 receiver. Now this is how it applies to us today. If one peruses the Ebay adds for HP test equipment one frequently sees a statement like *removed from a place that went out of business* or something similar. True, the equipment we are buying is 20 years old or older. But it is going away never to return. I saw an old Ebay invoice from 12 years ago where I won a working HP 3586B for $50. The shipping cost me more! Now a non-functional unit sells for $400. These prices are only going to continue to rise as the supply continues to diminish. But this equipment is repairable unlike the questionable test equipment from China. Doing preventative maintenance on this equipment is not optional if you want it to continue working. All electrolytic caps should be replaced, except for tantalums. That will be more on a case by case business. This is equipment you can repair. This is not very true for the newer stuff. On the HP 3586B for example, there are a dozen or so of TVA atoms. When I do mine I expect it will then lock below 500 KHz as it is specified. The HP 5370B needs far more cooling than provided. I have even given thought to adding additional resistances to the pass transistor collectors on the outside by the heat sink. I found on my two that the mother board was scorched from overheating by rectifier diodes. This will have to wait until after we have moved. I will also add EFC to the 10811 oscillator. (Why that feature was omitted can be answered by Ric). There are two long standing truths about electronic equipment. One you can’t have too much filter capacitance. Two, you can’t cool too much. (Please spare me the liquid nitrogen or submarine battery comments.) Regards, Perrier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
That works out to $118,480 in 2012 dollarettes. http://www.westegg.com/inflation/ Dave -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark C. Stephens Sent: Saturday, June 15, 2013 13:46 To: Perry Sandeen; Discussion of precise time andfrequency measurement Subject: Re: [time-nuts] HP and other equipment failure Hi Perry, I was browsing a 1988 HP catalogue tonight.. The 8566B came in at a cool 62 thousand dollars new. Wow! -marki -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Perry Sandeen Sent: Friday, 14 June 2013 2:48 PM To: time-nuts@febo.com Subject: [time-nuts] HP and other equipment failure All, There has been an on and off discussion of equipment failure so Id thought Id add my experience. First Ive been repairing HP equipment since 1976 before many of you were born. I now have over 16 pieces of HP test equipment and several units now need repair. In my experience, the vast amount of failures are electrolytic caps with some aggravated by heat. Someone floated the notion of not repairing HP equipment but cannibalizing it for parts. Please bear with me on my long story. After WWII there were all sorts of surplus stores selling everything in the mid-fifties. I even remember an add in popular Mechanics magazine for a Norden bombsite for $29.95. Much of my allowance was spent on mysterious wonders like a IFF receiver. Hams reveled in B-29 prop pitch motors for rotating beam antennas. Since it was 28 volt stuff it was far, far cheaper than commercial equivalents. Then it all gradually disappeared. Now people want $75 or more for a cruddy ARC-5 receiver. Now this is how it applies to us today. If one peruses the Ebay adds for HP test equipment one frequently sees a statement like *removed from a place that went out of business* or something similar. True, the equipment we are buying is 20 years old or older. But it is going away never to return. I saw an old Ebay invoice from 12 years ago where I won a working HP 3586B for $50. The shipping cost me more! Now a non-functional unit sells for $400. These prices are only going to continue to rise as the supply continues to diminish. But this equipment is repairable unlike the questionable test equipment from China. Doing preventative maintenance on this equipment is not optional if you want it to continue working. All electrolytic caps should be replaced, except for tantalums. That will be more on a case by case business. This is equipment you can repair. This is not very true for the newer stuff. On the HP 3586B for example, there are a dozen or so of TVA atoms. When I do mine I expect it will then lock below 500 KHz as it is specified. The HP 5370B needs far more cooling than provided. I have even given thought to adding additional resistances to the pass transistor collectors on the outside by the heat sink. I found on my two that the mother board was scorched from overheating by rectifier diodes. This will have to wait until after we have moved. I will also add EFC to the 10811 oscillator. (Why that feature was omitted can be answered by Ric). There are two long standing truths about electronic equipment. One you cant have too much filter capacitance. Two, you cant cool too much. (Please spare me the liquid nitrogen or submarine battery comments.) Regards, Perrier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
In message 1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com, Robert Atkinson writes: While I agree with everything else you say, you CAN have too much filter capacitance. At least where dc rectifier / filter (smoothing) circuits are concerned. Increasing C causes increased ripple current [...] And ripple current can be a major source of power-line frequency noise in all electronics. The main reason why switchmode power-supplies today (can) outperform linear power supplies with respect to noise, is because the legally mandated PFC correction eliminates the bridge-rectifier ripple harmonics. I would not hessitate to use a good quality switchmode to replace the linear supply in a HP5370B. I did some experiments a couple of years ago, with an audio-amplifier: I put a standard PFC corrector chip on the secondary side of the trafo. The overall result was not satisfactory, but the 50 Hz sneer we all know and hate was absent, and the Tzoing! power-on mechanical shock from the trafo was also eliminated, as was the consequent dimming of the lights ;-) The main reason not to do this, is that you need some physically gargantuan coils for a 10A+ PFC-switcher. -- 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
Sorry for the interruption but what is 'PFC'? Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Saturday, June 15, 2013 4:09 PM To: Robert Atkinson; Discussion of precise time and frequency measurement Cc: Perry Sandeen Subject: Re: [time-nuts] HP and other equipment failure In message 1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com, Robert Atkinson writes: While I agree with everything else you say, you CAN have too much filter capacitance. At least where dc rectifier / filter (smoothing) circuits are concerned. Increasing C causes increased ripple current [...] And ripple current can be a major source of power-line frequency noise in all electronics. The main reason why switchmode power-supplies today (can) outperform linear power supplies with respect to noise, is because the legally mandated PFC correction eliminates the bridge-rectifier ripple harmonics. I would not hessitate to use a good quality switchmode to replace the linear supply in a HP5370B. I did some experiments a couple of years ago, with an audio-amplifier: I put a standard PFC corrector chip on the secondary side of the trafo. The overall result was not satisfactory, but the 50 Hz sneer we all know and hate was absent, and the Tzoing! power-on mechanical shock from the trafo was also eliminated, as was the consequent dimming of the lights ;-) The main reason not to do this, is that you need some physically gargantuan coils for a 10A+ PFC-switcher. -- 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
Although off-topic here, the PFC (or power factor correction) is a switching mode front-end used to correct the cos-phi of the otherwise capacitive load that every switching mode power supply is for the mains. On Sat, Jun 15, 2013 at 11:52 PM, J. L. Trantham jlt...@att.net wrote: Sorry for the interruption but what is 'PFC'? Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Saturday, June 15, 2013 4:09 PM To: Robert Atkinson; Discussion of precise time and frequency measurement Cc: Perry Sandeen Subject: Re: [time-nuts] HP and other equipment failure In message 1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com, Robert Atkinson writes: While I agree with everything else you say, you CAN have too much filter capacitance. At least where dc rectifier / filter (smoothing) circuits are concerned. Increasing C causes increased ripple current [...] And ripple current can be a major source of power-line frequency noise in all electronics. The main reason why switchmode power-supplies today (can) outperform linear power supplies with respect to noise, is because the legally mandated PFC correction eliminates the bridge-rectifier ripple harmonics. I would not hessitate to use a good quality switchmode to replace the linear supply in a HP5370B. I did some experiments a couple of years ago, with an audio-amplifier: I put a standard PFC corrector chip on the secondary side of the trafo. The overall result was not satisfactory, but the 50 Hz sneer we all know and hate was absent, and the Tzoing! power-on mechanical shock from the trafo was also eliminated, as was the consequent dimming of the lights ;-) The main reason not to do this, is that you need some physically gargantuan coils for a 10A+ PFC-switcher. -- 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
Thanks. Now it makes sense. Sorry for the interruption. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Azelio Boriani Sent: Saturday, June 15, 2013 4:58 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP and other equipment failure Although off-topic here, the PFC (or power factor correction) is a switching mode front-end used to correct the cos-phi of the otherwise capacitive load that every switching mode power supply is for the mains. On Sat, Jun 15, 2013 at 11:52 PM, J. L. Trantham jlt...@att.net wrote: Sorry for the interruption but what is 'PFC'? Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Saturday, June 15, 2013 4:09 PM To: Robert Atkinson; Discussion of precise time and frequency measurement Cc: Perry Sandeen Subject: Re: [time-nuts] HP and other equipment failure In message 1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com, Robert Atkinson writes: While I agree with everything else you say, you CAN have too much filter capacitance. At least where dc rectifier / filter (smoothing) circuits are concerned. Increasing C causes increased ripple current [...] And ripple current can be a major source of power-line frequency noise in all electronics. The main reason why switchmode power-supplies today (can) outperform linear power supplies with respect to noise, is because the legally mandated PFC correction eliminates the bridge-rectifier ripple harmonics. I would not hessitate to use a good quality switchmode to replace the linear supply in a HP5370B. I did some experiments a couple of years ago, with an audio-amplifier: I put a standard PFC corrector chip on the secondary side of the trafo. The overall result was not satisfactory, but the 50 Hz sneer we all know and hate was absent, and the Tzoing! power-on mechanical shock from the trafo was also eliminated, as was the consequent dimming of the lights ;-) The main reason not to do this, is that you need some physically gargantuan coils for a 10A+ PFC-switcher. -- 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
Joe, With the tradition rectifier/filter power is only drawn on both side of the peak of the sine of line voltage, sort of like this: --- --- -| |--| | because the rectifier diodes only conduct when Vsupply Vcapacitor With a switching converter, using an inductor as an intermediate energy storage element, it is possible to draw current over more of the cycle. This is called PFC, but is not PFC in the true sense, which is only defined for sines. -John == Although off-topic here, the PFC (or power factor correction) is a switching mode front-end used to correct the cos-phi of the otherwise capacitive load that every switching mode power supply is for the mains. On Sat, Jun 15, 2013 at 11:52 PM, J. L. Trantham jlt...@att.net wrote: Sorry for the interruption but what is 'PFC'? Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Saturday, June 15, 2013 4:09 PM To: Robert Atkinson; Discussion of precise time and frequency measurement Cc: Perry Sandeen Subject: Re: [time-nuts] HP and other equipment failure In message 1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com, Robert Atkinson writes: While I agree with everything else you say, you CAN have too much filter capacitance. At least where dc rectifier / filter (smoothing) circuits are concerned. Increasing C causes increased ripple current [...] And ripple current can be a major source of power-line frequency noise in all electronics. The main reason why switchmode power-supplies today (can) outperform linear power supplies with respect to noise, is because the legally mandated PFC correction eliminates the bridge-rectifier ripple harmonics. I would not hessitate to use a good quality switchmode to replace the linear supply in a HP5370B. I did some experiments a couple of years ago, with an audio-amplifier: I put a standard PFC corrector chip on the secondary side of the trafo. The overall result was not satisfactory, but the 50 Hz sneer we all know and hate was absent, and the Tzoing! power-on mechanical shock from the trafo was also eliminated, as was the consequent dimming of the lights ;-) The main reason not to do this, is that you need some physically gargantuan coils for a 10A+ PFC-switcher. -- 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. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
PFC to me is power factor correction, not only the classical power factor to minimize (VAR) volt-amp reactive component, but also to remove the harmonic load current imposd on the electrical power system. A '90's onward technique. in th 80's and 90's without the harmonic load current reduction and having a few 100 end items of equipment, each withtheir own a switch mode power supplly, it was not uncommon to find hundreds of amps of the third harmonc on neutra, in the electrical power distribution system. Could be a serious EMC problem if you were dealing with voice grade channels. And people safety issues. Stan, W1LE Cape Cod On 15-Jun-13 5:52 PM, J. L. Trantham wrote: Sorry for the interruption but what is 'PFC'? Thanks. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Poul-Henning Kamp Sent: Saturday, June 15, 2013 4:09 PM To: Robert Atkinson; Discussion of precise time and frequency measurement Cc: Perry Sandeen Subject: Re: [time-nuts] HP and other equipment failure In message 1371329221.83869.yahoomail...@web171902.mail.ir2.yahoo.com, Robert Atkinson writes: While I agree with everything else you say, you CAN have too much filter capacitance. At least where dc rectifier / filter (smoothing) circuits are concerned. Increasing C causes increased ripple current [...] And ripple current can be a major source of power-line frequency noise in all electronics. The main reason why switchmode power-supplies today (can) outperform linear power supplies with respect to noise, is because the legally mandated PFC correction eliminates the bridge-rectifier ripple harmonics. I would not hessitate to use a good quality switchmode to replace the linear supply in a HP5370B. I did some experiments a couple of years ago, with an audio-amplifier: I put a standard PFC corrector chip on the secondary side of the trafo. The overall result was not satisfactory, but the 50 Hz sneer we all know and hate was absent, and the Tzoing! power-on mechanical shock from the trafo was also eliminated, as was the consequent dimming of the lights ;-) The main reason not to do this, is that you need some physically gargantuan coils for a 10A+ PFC-switcher. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
jlt...@att.net said: Sorry for the interruption but what is 'PFC'? For terms like that, Wikipedia is often a good first try. In this case, PFC goes to a disambiguation page and there are 9 possibilities under. A quick scan finds the interesting one. http://en.wikipedia.org/wiki/PFC -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure - availability
Greetings Gentlemen! I have been following the thread on HP equipment repair, as I have a bunch of it and am waiting the inevitable day when something starts to smoke. That being said, I agree with the gentlemen that say fixing is better than junking and also about the diminishing supply. The supply of 70-80-90's HP gear will shrink even more rapidly than you expect: This year at the Dayton Hamvention, a friend of mine, who is a fairly large surplus equipment dealer, did not sell. Instead he came only to buy: All older HP gear. He ran around the Fest buying every 3586, old logic analyzer, even an 8510 Network analyzer, all to strip out the boards with the gold plated lands. He bought an entire pickup truck worth, about $8000. and he assures me he will make money. In fact, he said he can sell the 10811A reference oscillators on eBay and pay for the individual piece, getting the gold scrap for free. He had numbers for gold yield for each item, so much per pound of board etc. Now whether you agree about the return on gold scrap doesn't matter. The thing is, he is making a dent in the number of pieces available on the market. Stuff will get rarer. I once saw a surplus store crammed with wire- teflon, pvc, mil-spec, enamel, all gauges and colors, price was cheap, used rolls of 22 ga. teflon, 500+ feet were $10-15. A few months later, I went again, ALL GONE! Store cleaned out! When I asked Wolf, the owner what happened, he said Price of copper went up Nothing lasts forever, which is why I pile stuff up for my own use. As to surplus, I like to say I was at the party when the booze ran out 73, Jeff Kruth WA3ZKR ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure - availability
Oh that is so sad, Trying to track down parts to find that some scrap metal merchant has melted it down. And to think a surplus dealer would knowingly scrap HP test equipment is just plain sacrilege. All those custom IC's and PROMS m e l t e d . . God help us down under if any of the scrappers hear this. It's hard enough to find bits here without competing with scrap metal merchants. -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of k...@aol.com Sent: Sunday, 16 June 2013 10:34 AM To: time-nuts@febo.com Subject: Re: [time-nuts] HP and other equipment failure - availability Greetings Gentlemen! I have been following the thread on HP equipment repair, as I have a bunch of it and am waiting the inevitable day when something starts to smoke. That being said, I agree with the gentlemen that say fixing is better than junking and also about the diminishing supply. The supply of 70-80-90's HP gear will shrink even more rapidly than you expect: This year at the Dayton Hamvention, a friend of mine, who is a fairly large surplus equipment dealer, did not sell. Instead he came only to buy: All older HP gear. He ran around the Fest buying every 3586, old logic analyzer, even an 8510 Network analyzer, all to strip out the boards with the gold plated lands. He bought an entire pickup truck worth, about $8000. and he assures me he will make money. In fact, he said he can sell the 10811A reference oscillators on eBay and pay for the individual piece, getting the gold scrap for free. He had numbers for gold yield for each item, so much per pound of board etc. Now whether you agree about the return on gold scrap doesn't matter. The thing is, he is making a dent in the number of pieces available on the market. Stuff will get rar er. I once saw a surplus store crammed with wire- teflon, pvc, mil-spec, enamel, all gauges and colors, price was cheap, used rolls of 22 ga. teflon, 500+ feet were $10-15. A few months later, I went again, ALL GONE! Store cleaned out! When I asked Wolf, the owner what happened, he said Price of copper went up Nothing lasts forever, which is why I pile stuff up for my own use. As to surplus, I like to say I was at the party when the booze ran out 73, Jeff Kruth WA3ZKR ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
On 14 June 2013 05:48, Perry Sandeen sandee...@yahoo.com wrote: There are two long standing truths about electronic equipment. One you can’t have too much filter capacitance. Two, you can’t cool too much. (Please spare me the liquid nitrogen or submarine battery comments.) Regards, Perrier Well, I have to disagree with both comments. More filter capacitance in a standard linear power supply means the diodes take more current for a longer period of time. For any given diode, that puts more strain on it. At very high levels of capacitance, the amount of stored energy is huge, and can be dangerous. In the event of a fault, higher stored energy has the potential to do more damage than lower stored energy. Once you have sufficient capacitance, which includes calculating the effects of reduced supply voltage, minimum capacitance of device with tolerances, and some safety factor, I don't see what more capacitance does other than increase costs, weight, and the potential for more damage in the event of a fault. Whilst it is well known that increasing temperature gives rise to shorter component lifetimes, more cooling also requires more noise, and so a compromise has to be met. I have here an Air Control Industries VBL9 blower, which I want to sell in fact. That will move about 1000 cfm at 6 of water pressure. It happens to take 2.8 kW from the mains, the startup current is too large to not blow a normal mains fuse in a plug here in the UK, and the noise is enough to get neighbours wondering what the hell it is, despite I live in a detached house, some 50 m from the nearest property. So while a HP 5370B needs far more cooling than provided, I think the VBL9 would certainly provide too much cooling air. Engineering is always a compromise. HP usually got that balance about right, although in some instances, like the 5370B, that is not true. I know mine got pretty damm hot, and I'm quite near sea level. I would imagine for someone at a high altitude, it would be even worst. I have to agree with you about the serviceability of older HP equipment though. It is much more serviceable than modern equipment. However, you would have to go back a long way before finding equipment which one could guarantee one could keep going, as most things I'd contemplate buying will have a ASIC and/or some other specialist component which if it failed would be impossible to get except by taking one from a similar piece of equipment. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
Talking of Cooling HP 5370's, I have a 12V fan Gorilla taped to mine fed from a wallwart. Not elegant, but it has reduced the heat sink temperature dramatically. Is anyone else concerned about the heat sink temperature on the 5370? Has anyone done a fan modification they would care to share? Also, my 8566A RF section pass transistor heat sink gets awfully warm too, does anyone have a sensible solution? -marki -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David Kirkby Sent: Friday, 14 June 2013 7:14 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP and other equipment failure On 14 June 2013 05:48, Perry Sandeen sandee...@yahoo.com wrote: There are two long standing truths about electronic equipment. One you can't have too much filter capacitance. Two, you can't cool too much. (Please spare me the liquid nitrogen or submarine battery comments.) Regards, Perrier Well, I have to disagree with both comments. More filter capacitance in a standard linear power supply means the diodes take more current for a longer period of time. For any given diode, that puts more strain on it. At very high levels of capacitance, the amount of stored energy is huge, and can be dangerous. In the event of a fault, higher stored energy has the potential to do more damage than lower stored energy. Once you have sufficient capacitance, which includes calculating the effects of reduced supply voltage, minimum capacitance of device with tolerances, and some safety factor, I don't see what more capacitance does other than increase costs, weight, and the potential for more damage in the event of a fault. Whilst it is well known that increasing temperature gives rise to shorter component lifetimes, more cooling also requires more noise, and so a compromise has to be met. I have here an Air Control Industries VBL9 blower, which I want to sell in fact. That will move about 1000 cfm at 6 of water pressure. It happens to take 2.8 kW from the mains, the startup current is too large to not blow a normal mains fuse in a plug here in the UK, and the noise is enough to get neighbours wondering what the hell it is, despite I live in a detached house, some 50 m from the nearest property. So while a HP 5370B needs far more cooling than provided, I think the VBL9 would certainly provide too much cooling air. Engineering is always a compromise. HP usually got that balance about right, although in some instances, like the 5370B, that is not true. I know mine got pretty damm hot, and I'm quite near sea level. I would imagine for someone at a high altitude, it would be even worst. I have to agree with you about the serviceability of older HP equipment though. It is much more serviceable than modern equipment. However, you would have to go back a long way before finding equipment which one could guarantee one could keep going, as most things I'd contemplate buying will have a ASIC and/or some other specialist component which if it failed would be impossible to get except by taking one from a similar piece of equipment. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
About the HP5370 please got o see my solution to: http://www.timeok.it/files/hp_5370a_temperature_solution.pdf Luciano timeok see : www.timeok.it On Fri, Jun 14, 2013 at 4:26 PM, Mark C. Stephens ma...@non-stop.com.auwrote: Talking of Cooling HP 5370's, I have a 12V fan Gorilla taped to mine fed from a wallwart. Not elegant, but it has reduced the heat sink temperature dramatically. Is anyone else concerned about the heat sink temperature on the 5370? Has anyone done a fan modification they would care to share? Also, my 8566A RF section pass transistor heat sink gets awfully warm too, does anyone have a sensible solution? -marki -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David Kirkby Sent: Friday, 14 June 2013 7:14 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP and other equipment failure On 14 June 2013 05:48, Perry Sandeen sandee...@yahoo.com wrote: There are two long standing truths about electronic equipment. One you can't have too much filter capacitance. Two, you can't cool too much. (Please spare me the liquid nitrogen or submarine battery comments.) Regards, Perrier Well, I have to disagree with both comments. More filter capacitance in a standard linear power supply means the diodes take more current for a longer period of time. For any given diode, that puts more strain on it. At very high levels of capacitance, the amount of stored energy is huge, and can be dangerous. In the event of a fault, higher stored energy has the potential to do more damage than lower stored energy. Once you have sufficient capacitance, which includes calculating the effects of reduced supply voltage, minimum capacitance of device with tolerances, and some safety factor, I don't see what more capacitance does other than increase costs, weight, and the potential for more damage in the event of a fault. Whilst it is well known that increasing temperature gives rise to shorter component lifetimes, more cooling also requires more noise, and so a compromise has to be met. I have here an Air Control Industries VBL9 blower, which I want to sell in fact. That will move about 1000 cfm at 6 of water pressure. It happens to take 2.8 kW from the mains, the startup current is too large to not blow a normal mains fuse in a plug here in the UK, and the noise is enough to get neighbours wondering what the hell it is, despite I live in a detached house, some 50 m from the nearest property. So while a HP 5370B needs far more cooling than provided, I think the VBL9 would certainly provide too much cooling air. Engineering is always a compromise. HP usually got that balance about right, although in some instances, like the 5370B, that is not true. I know mine got pretty damm hot, and I'm quite near sea level. I would imagine for someone at a high altitude, it would be even worst. I have to agree with you about the serviceability of older HP equipment though. It is much more serviceable than modern equipment. However, you would have to go back a long way before finding equipment which one could guarantee one could keep going, as most things I'd contemplate buying will have a ASIC and/or some other specialist component which if it failed would be impossible to get except by taking one from a similar piece of equipment. Dave ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Luciano Timeok visit : www.timeok.it ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
Re: HP5370B cooling. I currently have three HP5370B's that have been running for many months in a cool room (typical room temperature is under 20 degrees C even in the summer) so far without issues. Other than placing them away from other heat producing equipment and and double checking the ac line voltage supplied to them from a UPS system and the voltage setting of the power supply no special precautions were taken. In the winter they provide useful heat to an otherwise cool room in my basement. Your mileage may vary (: One trick I've used on other older equipment with linear power supplies is to reduce the AC line voltage (the exact voltage depends on the equipment in question) using a variac, to cut down on the power that the pass tranistors in the power supplies need to disipate. I've never bothered to do this with the HP5370B's but I be inclined to go down this road before I started blowing extra air over them with fans. In general I agree with the comments about the serviceability of the older HP gear. I'm hopefull that I can keep at least two of my four HP5370B's working for many years to come. Regards Mark Spencer -- Message: 1 Date: Fri, 14 Jun 2013 14:26:50 + From: Mark C. Stephens ma...@non-stop.com.au To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] HP and other equipment failure Message-ID: 6c1fe0e5a70c9640b597f869a899c017032f0...@tmpexch.non-stop.com.au Content-Type: text/plain; charset=us-ascii Talking of Cooling HP 5370's, I have a 12V fan Gorilla taped to mine fed from a wallwart. Not elegant, but it has reduced the heat sink temperature dramatically. Is anyone else concerned about the heat sink temperature on the 5370? Has anyone done a fan modification they would care to share? Also, my 8566A RF section pass transistor heat sink gets awfully warm too, does anyone have a sensible solution? -marki ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP and other equipment failure
Luciano wrote: About the HP5370 please got o see my solution The fans would cool the transistors better if they were blowing on the heatsink fins, not directly at the transistors. I use a slow fan that is large enough to blow over the whole heatsink assembly. You can't hear it over the noise of the internal fan, and the transistors run at 35C. Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] HP and other equipment failure...
My HP-3336A was purchased from an auction (not eBay) and came out of a Southern California lab that was shutting down. The small heat sink ran awfully hot. I added a larger heat sink and it eventually became pretty hot also. What I discovered was the line voltage was set to 100 volts, not 120 volts. I know for sure that this instrument was used in the US. Changing it to 110-120 resolved the problem and it now runs cool. I should've checked the line voltage setting when it arrived, but I just assumed... Burt, K6OQK Subject: Re: [time-nuts] HP and other equipment failure Talking of Cooling HP 5370's, I have a 12V fan Gorilla taped to mine fed from a wallwart. Not elegant, but it has reduced the heat sink temperature dramatically. Is anyone else concerned about the heat sink temperature on the 5370? Has anyone done a fan modification they would care to share? Also, my 8566A RF section pass transistor heat sink gets awfully warm too, does anyone have a sensible solution? -marki Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] HP and other equipment failure
All, There has been an on and off discussion of equipment failure so I’d thought I’d add my experience. First I’ve been repairing HP equipment since 1976 before many of you were born. I now have over 16 pieces of HP test equipment and several units now need repair. In my experience, the vast amount of failures are electrolytic caps with some aggravated by heat. Someone floated the notion of not repairing HP equipment but cannibalizing it for parts. Please bear with me on my long story. After WWII there were all sorts of surplus stores selling everything in the mid-fifties. I even remember an add in popular Mechanics magazine for a Norden bombsite for $29.95. Much of my allowance was spent on mysterious wonders like a IFF receiver. Hams reveled in B-29 prop pitch motors for rotating beam antennas. Since it was 28 volt stuff it was far, far cheaper than commercial equivalents. Then it all gradually disappeared. Now people want $75 or more for a cruddy ARC-5 receiver. Now this is how it applies to us today. If one peruses the Ebay adds for HP test equipment one frequently sees a statement like *removed from a place that went out of business* or something similar. True, the equipment we are buying is 20 years old or older. But it is going away never to return. I saw an old Ebay invoice from 12 years ago where I won a working HP 3586B for $50. The shipping cost me more! Now a non-functional unit sells for $400. These prices are only going to continue to rise as the supply continues to diminish. But this equipment is repairable unlike the questionable test equipment from China. Doing preventative maintenance on this equipment is not optional if you want it to continue working. All electrolytic caps should be replaced, except for tantalums. That will be more on a case by case business. This is equipment you can repair. This is not very true for the newer stuff. On the HP 3586B for example, there are a dozen or so of TVA atoms. When I do mine I expect it will then lock below 500 KHz as it is specified. The HP 5370B needs far more cooling than provided. I have even given thought to adding additional resistances to the pass transistor collectors on the outside by the heat sink. I found on my two that the mother board was scorched from overheating by rectifier diodes. This will have to wait until after we have moved. I will also add EFC to the 10811 oscillator. (Why that feature was omitted can be answered by Ric). There are two long standing truths about electronic equipment. One you can’t have too much filter capacitance. Two, you can’t cool too much. (Please spare me the liquid nitrogen or submarine battery comments.) Regards, Perrier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
