Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
Hugh, You must be the only one this ever happened to ;) Didier KO4BB On Sun, Feb 10, 2019, 7:06 PM Rice, Hugh (IPH Writing Systems) < hugh.r...@hp.com> wrote: > > Putting things in writing and disclosing it to the public is a risky > undertaking! > > Best wishes, > Hugh > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
On 10/2/19 11:18 pm, Rice, Hugh (IPH Writing Systems) wrote: > The AC transformer in the 5061A/B was from HPs transformer organization (HP > actually made their own transformers for many years), and whoever designed > the original power system left a lot of "brown out" margin in the system. > There is a "115/230" switch on the primary side of the transformer, but the > system was designed to work well in low voltage 100 VAC countries.The > input AC voltage could go down quite a lot before the main 18.7V power > throughout the 5061A/B would start to wilt. Whilst that's nice for some cases, it does mean that if your line voltage is a tad on the high side (despite nowadays being a nominal 230v country 252v is pretty standard inner-city line voltage in Australia, 260v is out of spec, but not unheard of) you end up dumping a heap of power as heat. This of course often hurts the lifetime of kit. Back in the day you'd have transformers with separate 220v & 240v taps for this purpose, but they've become fairly rare. I've been tempted to get 240:220v autotransformers for some more notable bits of kit that are affected badly by this, but so far haven't bothered. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
Sorry, perhaps off-topic but relevant given the pursuit of mineral mining globally. In 1968, the U.S. Bureau of Mines had a very accurate model (pre-econometric, if there is such a thing) of Mica production in India down to the State level (primarily Bihar - the poorest state in India). As a college student, I never understood why. A decade or so later in as a "professional student in another country", it dawned upon me why this information was relevant. On 2/10/19 7:13 PM, Bruce Griffiths wrote: Mica is a sheet silicate mineral little or no carbon present. Bruce On 11 February 2019 at 11:15 Bob Bownes wrote: Yes, those brown roughly 1" square caps used intact sheets of mica as dielectric. You can easily split the mineral into uniform, thin, transparent sheets. Beware inclusions that will make the surface rough and change the behavior, particularly breakdown voltages. The reconstituted caps are still around - used in high power RF circuits (mica has really low loss, but high epsilon) and in Tesla coils (a sort of special case high power RF). Most of them are surplus Russian/Soviet. Hmm, mica is pretty much hexagonal version of graphite/carbon/diamond created when there is a large axial force and the proper temperature. It is synthesized for many uses today, I’d be very surprised if precision high voltage caps was not one of them. That being said, thanks for the insights into the 5061A/B. Now I feel the need to go power mine up! ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
Brings to mind two interesting numbers: I figured out when I was ten that it takes about 2 weeks to count to a million at one number/sec. Much later in graduate school I learned from an astronomer that a year has pi x 10^7 seconds. Andy Backus From: time-nuts on behalf of Mark Sims Sent: Sunday, February 10, 2019 5:37 PM To: time-nuts@lists.febo.com Subject: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP Back in the late 70's I worked for a mini-computer company. They were a horrendous paper-work factory... spec after needless/useless/virtually identical documentation requirements. I wrote one document where I put all the timings in units of "ffn"... femto-fortnights. It was over three years later that somebody asked me what a "ffn" is. After 5 years, he and I were the only people to ever request a copy of that document. -- >“Hey, no one will notice that the stamping on the transistor doesn’t match the >parts list. I’ll bet no one will look at this schematic carefully anyway. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
On 2/10/19 4:36 PM, Tom Van Baak wrote: Christopher Shawn McGahey's wrote his phd at Georgia Tech on the subject, and it sorts a lot of facts from fiction. "HARNESSING NATURE'S TIMEKEEPER: A HISTORY OF THE PIEZOELECTRIC QUARTZ CRYSTAL TECHNOLOGICAL COMMUNITY (1880-1959)" https://smartech.gatech.edu/bitstream/handle/1853/28255/mcgahey_christopher_s_200905_phd.pdf by Christopher Shawn McGahey, Georgia Institute of Technology, May 2009 This is an awesome work.. although some of the clever turns of phrase are a bit of a groaner... [patent filing] activity declined and oscillated If I meet him, I'll buy him a beer. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
Back in the late 70's I worked for a mini-computer company. They were a horrendous paper-work factory... spec after needless/useless/virtually identical documentation requirements. I wrote one document where I put all the timings in units of "ffn"... femto-fortnights. It was over three years later that somebody asked me what a "ffn" is. After 5 years, he and I were the only people to ever request a copy of that document. -- >“Hey, no one will notice that the stamping on the transistor doesn’t match the >parts list. I’ll bet no one will look at this schematic carefully anyway. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
Mica is a sheet silicate mineral little or no carbon present. Bruce > On 11 February 2019 at 11:15 Bob Bownes wrote: > > > > > > Yes, those brown roughly 1" square caps used intact sheets of mica as > > dielectric. You can easily split the mineral into uniform, thin, > > transparent sheets. > > Beware inclusions that will make the surface rough and change the behavior, > particularly breakdown voltages. > > > The reconstituted caps are still around - used in high power RF circuits > > (mica has really low loss, but high epsilon) and in Tesla coils (a sort of > > special case high power RF). Most of them are surplus Russian/Soviet. > > > Hmm, mica is pretty much hexagonal version of graphite/carbon/diamond created > when there is a large axial force and the proper temperature. It is > synthesized for many uses today, I’d be very surprised if precision high > voltage caps was not one of them. > > That being said, thanks for the insights into the 5061A/B. Now I feel the > need to go power mine up! > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
Luca wrote: > There is a little strangeness: the wave clipper darlington transistor Q1 is > marked as 1854-0611, equivalent to the standard darlington 2N6055. But why > there is a simple 2N3055 in the picture? Some sort of version update fail? One other reader (Ian) pointed out this same discrepancy, and there clearly is a part number error somewhere.I remember using the Darlington device on purpose, because with its higher gain, it took a less base current to accomplish the wave clipper job I used it for. As you can see, getting these details right in documentation is challenging. I remember working on it pretty hard, and this one got past me. Who knows, for the photo shoot of the PCA, I may have just stuck the wrong part in there because I didn’t have the right one on had that day. “Hey, no one will notice that the stamping on the transistor doesn’t match the parts list. I’ll bet no one will look at this schematic carefully anyway. Take the picture.”Never knowing that 30 years later, some “time-nut” would scrutinize the photo vs. the schematic, and point out to me “those numbers don’t match!” Putting things in writing and disclosing it to the public is a risky undertaking! Best wishes, Hugh From: time-nuts On Behalf Of Luca Sent: Sunday, February 10, 2019 8:55 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP Thanks Hugh for the story, and thanks for the schematic! Quite interesting. There is a little strangeness: the wave clipper darlington transistor Q1 is marked as 1854-0611, equivalent to the standard darlington 2N6055. But why there is a simple 2N3055 in the picture? Some sort of version update fail? Thanks Cheers Luca iw2lje Il giorno sabato 9 febbraio 2019, Rice, Hugh (IPH Writing Systems) < hugh.r...@hp.com<mailto:hugh.r...@hp.com>> ha scritto: ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
> Christopher Shawn McGahey's wrote his phd at Georgia Tech on the subject, > and it sorts a lot of facts from fiction. "HARNESSING NATURE'S TIMEKEEPER: A HISTORY OF THE PIEZOELECTRIC QUARTZ CRYSTAL TECHNOLOGICAL COMMUNITY (1880-1959)" https://smartech.gatech.edu/bitstream/handle/1853/28255/mcgahey_christopher_s_200905_phd.pdf by Christopher Shawn McGahey, Georgia Institute of Technology, May 2009 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
> > Yes, those brown roughly 1" square caps used intact sheets of mica as > dielectric. You can easily split the mineral into uniform, thin, transparent > sheets. Beware inclusions that will make the surface rough and change the behavior, particularly breakdown voltages. > The reconstituted caps are still around - used in high power RF circuits > (mica has really low loss, but high epsilon) and in Tesla coils (a sort of > special case high power RF). Most of them are surplus Russian/Soviet. > Hmm, mica is pretty much hexagonal version of graphite/carbon/diamond created when there is a large axial force and the proper temperature. It is synthesized for many uses today, I’d be very surprised if precision high voltage caps was not one of them. That being said, thanks for the insights into the 5061A/B. Now I feel the need to go power mine up! ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
> were made from large contiguous chunks of mica. A some point after > the war, the mica mines were played out, similar to the quartz mines, > and only small pieces of mica were available. The capacitor vendors > made "reconstituted" mica out of crumbs. The crystal vendors didn't > have that option so they had to invent synthetic quartz. As far as Quartz, that's not quite accurate. The quartz mines were more or less empty to begin with, in the sense that there were very little of what was mined which could be used for frequency control, primarily because "twining" is a very frequent phenomena in quartz (the energy difference is practically zero). Growing artificial quartz had been a research project for many years prior to the second world war, and while the war put it in focus, it played practically no practical role, instead the war focus was on getting more out of the natural quartz available, smaller crystals, higher frequencies and so on. Only after WWII, when Bell-Labs realized that quartz *could* be grown, and they carried out a lot of brute-force parameterization experiments, did synthetic quartz take over. Christopher Shawn McGahey's wrote his phd at Georgia Tech on the subject, and it sorts a lot of facts from fiction. -- 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@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
On 2/10/2019 4:35 AM, Rice, Hugh (IPH Writing Systems) wrote: Somewhere over the years I picked up this line: “A good engineer is a lazy engineer. They are always looking for the easiest way to do things.” The designer of the 5061A battery charger was definitely not a lazy engineer. Cheers, Hugh Rice As Hugh writes about the "ghost engineer" (analogous to "ghost writer") behind the charger, I can't help thinking about Len Cutler for at least 3 reasons: 1. Len was the leader of the flying clock mission. I can easily imagine that Len wanted the fast recharge capability based either on some actual incident concerning the flying clocks, or it could just be Len being a perfectionist. Len will be Len. The 10 dB design margin philosophy was a constant point of discussion during the 5071 project. The results speak for themselves. 2. The giant unobtainable mica capacitor has Len's fingerprints all over it. On the 5071, Len wanted to use a tantalum capacitor for the power supply filter. Imagine what that cap would now cost in these days of "conflict minerals". The project team mutinied and Len backed down. It was all moot anyway after we decided to use Vicor modules. That seemed very avante garde at the time, but now seems sensible. BTW, I heard the those giant WWII military mica capacitors were made from large contiguous chunks of mica. A some point after the war, the mica mines were played out, similar to the quartz mines, and only small pieces of mica were available. The capacitor vendors made "reconstituted" mica out of crumbs. The crystal vendors didn't have that option so they had to invent synthetic quartz. 3. "A good engineer is a lazy engineer". Definitely not in Len's wheelhouse. When I replaced the harmonic generator with a phase locked DRO, Len didn't have any real technical criticisms of it, but scolded me for "taking the easy way out." Hugh's comment about the disconnect between the architect defining the design and the engineer implementing the design is right on target. As I got more experience in engineering, it became clear that the architect is responsible for 95% of the success or failure of the project. Hugh is to be congratulated for putting on his architect's hat instead of throwing good money after bad. Rick ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
In reading back over my sarcastic description of the 5061A battery charger, I was pretty hard on the unnamed designer of that circuit. I did find a schematic of an older generation batter charger for the 5061A, and it had the same basic implementation. As far as I know, the circuit, in all it’s complexity, was reliable, and causing no field problems. This really is the most important aspect. For low volume products, another $5 of component cost, on an instrument that sells for $20,000+, isn’t material. A guess on what happened, to cut this dude some slack: As all of you know, the most important aspect of any design is the original definition, or objective for the circuit.Many times, the circuit designer is not the “architect” of the system, and is just implementing what they are told to do. Maybe the lead system designer wanted a fast recovery circuit for the batter charger, because marketing wanted to push the feature about how the system would be back to full capacity quickly.Who knows? While the implementation had some excessively complicated details, the bigger issue was the requirement for a fast/slow charge, which I felt was unnecessary. This first designer may not have had the freedom to make that decision. While working on the circuit, I first started developing my now very strong bias towards “elegant simplicity” in my designs, that I have carried forward to this day. I’m sure I got a lot of encouragement from some of the older HP engineers to think this way.I hate complexity that doesn’t add value. I don’t find it cool or exciting, just a waste.I am not a good engineer on programs that want to bling out a system with lots of fluff. Somewhere over the years I picked up this line: “A good engineer is a lazy engineer. They are always looking for the easiest way to do things.” The designer of the 5061A battery charger was definitely not a lazy engineer. Cheers, Hugh Rice _ From: Rice, Hugh (IPH Writing Systems) Sent: Saturday, February 9, 2019 10:31 PM To: 'time-nuts@lists.febo.com' Cc: 'hug...@yahoo.com' Subject: HP Stories: Battery Chargers, and a fading idolization of HP I grew up on Silicon Valley (Santa Clara Valley, California), graduating from High School in 1980. My home town is Cupertino, also the home of Apple Computer.During my formative teen years in the 1970s, HP was THE company in the valley, the elder statesmen of Hi-Tech. (Apple was just a small upstart business for computer geeks, and their headquarters were just down Bubb Road from my HS.) The reputation of HP as a great company was untouchable. Both in the quality of the products, and as a the best place to work. Being from Silicon Valley, I choose to study electrical engineering (rather than my natural inclination towards mechanical engineering, having done a lot of work on cars and bicycles), hoping to come back to the area to work when I graduated.I had fantasies of working for HP in my college summers as a “SEED” student, but was never able to make the right connections.A HP job upon graduation with a BSEE was like winning the lottery, especially for a Silicon Valley Kid. Home for Christmas during my senior year, I was visiting a friend from church, and her dad (Charles Adams) asked me how my job search was going, and if I had considered working for HP. “I’d LOVE to work for HP. I just can’t crack in and get an interview.”He said they had an opening for a new grad EE, and asked if I would be interested in considering it. “Uh, yes!” A few days later, I was in the Precision Frequency Sources Production Engineering area, doing the all day rounds of a classic HP interview. I did well enough that they offered me a job the next day, and I went back to school for my final semester with a HP job in hand. A certifiable miracle.It didn’t get any better than this. I asked Charles what I could do to prepare for the job, and he mailed me a 5061A Operating and Service Manual to review. It was incomprehensible. But I could tell that the 5061A was something pretty special, because all the circuit diagrams and theory of operation descriptions had things in them that even the grad students I knew couldn’t understand. And I had a job at HP! Working on Atomic Clocks!(Whatever they were.) As you know from past postings, my job was part of the 5061A to 5061B development team. The first task I was assigned to was to freshen up A2 Battery Charger Assembly. The purpose of this circuit was to keep the 20 cell NiCad backup battery ready to supply power in emergencies. The must fix issue was a gigantic mica capacitor used in a RC timing circuit, which was both expensive and unprocurable.I think my mentor, Roberto, encouraged me to look over the whole circuit, and sift out all the other old parts that would a problem in the near future. (All
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
Hi Poul - I'm only familiar with the system design for the 5061A/B, and can't really speak to a general HP T design approach. Maybe Rick has some insights. My real expertise is HP Inkjet printers, but those stories are for another mailing list. Reaching back to the 5060A, I think Lou Mueller once told me that Len Cutler, in the original system design, decreed that every module would have "10dB of margin".Not sure what that was compared to, but the idea is that he wanted a very reliable, very high margin design. The AC transformer in the 5061A/B was from HPs transformer organization (HP actually made their own transformers for many years), and whoever designed the original power system left a lot of "brown out" margin in the system.There is a "115/230" switch on the primary side of the transformer, but the system was designed to work well in low voltage 100 VAC countries.The input AC voltage could go down quite a lot before the main 18.7V power throughout the 5061A/B would start to wilt. Hugh -Original Message- From: Poul-Henning Kamp Sent: Sunday, February 10, 2019 1:02 AM To: Discussion of precise time and frequency measurement ; Rice, Hugh (IPH Writing Systems) Cc: 'hug...@yahoo.com' Subject: Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP Hugh, I notice your design, like all other HP designs I have seen from that era, operates with a very high margin for low mains voltage. Do you happen to remember what HP's design criteria were for this ? -- 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@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
The 5061A/B is the only HP T product that I worked on deeply, and yes, the manual is very complete and accurate, save a typo here or there.One careful reader (Ian) pointed out a typo in the generic 2N part number for the main TO-3 power transistor! The product family was old enough that the service manual was effectively the master copy of the schematics, for both internal HP use and external use. I have no memory of any official schematics stored or archived anywhere else. That may just be my bad memory though. I'm sure I drew up schematics for my own designs, but don't remember "checking them in", or making official copies of them. Official parts list, or bill of materials, were of course computerized by the 1980s, and drove the MRP (materials resource planning) process for purchasing components for manufacturing. Hugh From: time-nuts On Behalf Of Adrian Godwin Sent: Sunday, February 10, 2019 3:57 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP The schematics are so good - easy to read, lots of context. Even some off-board parts shown so you can see where the signal ends up. Notes about the function and adjustment. You can learn a lot from them. Manuals were worth having. So many of today's schematics are little more than a netlist : a bunch of fragmented sections with no way to find how they link up (maybe net names but you can't tell if they have 2 ends or several). Useless even for troubleshooting, let alone education. On Sat, Feb 9, 2019 at 6:08 PM Poul-Henning Kamp mailto:p...@phk.freebsd.dk>> wrote: > Hugh, > > I notice your design, like all other HP designs I have seen from > that era, operates with a very high margin for low mains voltage. > > Do you happen to remember what HP's design criteria were for this ? > > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > p...@freebsd.org<mailto: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@lists.febo.com<mailto:time-nuts@lists.febo.com> > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com<http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com> > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com<mailto:time-nuts@lists.febo.com> To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com<http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com> and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
Thanks Hugh for the story, and thanks for the schematic! Quite interesting. There is a little strangeness: the wave clipper darlington transistor Q1 is marked as 1854-0611, equivalent to the standard darlington 2N6055. But why there is a simple 2N3055 in the picture? Some sort of version update fail? Thanks Cheers Luca iw2lje Il giorno sabato 9 febbraio 2019, Rice, Hugh (IPH Writing Systems) < hugh.r...@hp.com> ha scritto: > I grew up on Silicon Valley (Santa Clara Valley, California), graduating > from High School in 1980. My home town is Cupertino, also the home of > Apple Computer.During my formative teen years in the 1970s, HP was THE > company in the valley, the elder statesmen of Hi-Tech. (Apple was just a > small upstart business for computer geeks, and their headquarters were just > down Bubb Road from my HS.) The reputation of HP as a great company was > untouchable. Both in the quality of the products, and as a the best place > to work. Being from Silicon Valley, I choose to study electrical > engineering (rather than my natural inclination towards mechanical > engineering, having done a lot of work on cars and bicycles), hoping to > come back to the area to work when I graduated.I had fantasies of > working for HP in my college summers as a “SEED” student, but was never > able to make the right connections.A HP job upon graduation with a BSEE > was like winning the lottery, especially for a Silicon Valley Kid. > > Home for Christmas during my senior year, I was visiting a friend from > church, and her dad (Charles Adams) asked me how my job search was going, > and if I had considered working for HP. “I’d LOVE to work for HP. I just > can’t crack in and get an interview.”He said they had an opening for a > new grad EE, and asked if I would be interested in considering it. “Uh, > yes!” A few days later, I was in the Precision Frequency Sources > Production Engineering area, doing the all day rounds of a classic HP > interview. I did well enough that they offered me a job the next day, and > I went back to school for my final semester with a HP job in hand. A > certifiable miracle.It didn’t get any better than this. > > I asked Charles what I could do to prepare for the job, and he mailed me a > 5061A Operating and Service Manual to review. It was incomprehensible. > But I could tell that the 5061A was something pretty special, because all > the circuit diagrams and theory of operation descriptions had things in > them that even the grad students I knew couldn’t understand. And I had a > job at HP! Working on Atomic Clocks!(Whatever they were.) > > As you know from past postings, my job was part of the 5061A to 5061B > development team. The first task I was assigned to was to freshen up A2 > Battery Charger Assembly. The purpose of this circuit was to keep the 20 > cell NiCad backup battery ready to supply power in emergencies. The must > fix issue was a gigantic mica capacitor used in a RC timing circuit, which > was both expensive and unprocurable.I think my mentor, Roberto, > encouraged me to look over the whole circuit, and sift out all the other > old parts that would a problem in the near future. (All that code 4 part > stuff.) > > So I studied the circuit like only a new grad can do. Brand new > engineers are nearly worthless, and no one has any reason to talk to them > or distract them. This was before the internet, cell phones, email (at my > location), and any other distraction. I had hours and hours of > uninterrupted time.The circuit was strikingly complex for a battery > charger.But you have to remember by frame of reference. HP was the > best electrical engineering company in the world. Their products were > awesome. Surely every circuit in every product was the result of deep > expertise from brilliant engineers, and every resistor, capacitor and > transistor had a sacred purpose.So I kept digging until I understood > every aspect of the circuit. > > The “brilliant” designer had decided that the battery charger needed to be > a two-level system. A fast charge to replenish the battery quickly after > a power failure, and then a lower “trickle” charge to keep it topped off > long term. But how long to do the fast charge?Well, if we time the > discharge time, we can then use that to set the fast charge time. Battery > power for 20 minutes? Fast charge 20 minutes at a similar rate.In > addition, the charger assembly had a drop-out relay circuit, so if the > battery voltage got too low, the relay would trip to disconnect the battery > protect it from over discharge. (Oh yes, the relay used was also > impossible to procure, being some ridiculous double pole, double throw, > part unique to the 5061A). Add another circuit to flash the front panel > light when the back-up battery was supplying power. And then the charge > current regulator itself, which of course was a transistor
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
Well lately I have been disappointed with the quality of writing of the manuals. Not just HP, but I do expect better from them. Typos, poor grammar, occasionally poor content. Very little said about errors that appear on screen, for instance. Sometimes I wonder if the circuits and software are of the same caliber. My early HP documentation was much better, of course for simpler units. Still, the stuff is very good and I am happy to have it. Even better, HP has set an example that others feel they need to follow. Bob On Saturday, February 9, 2019, 3:00:25 PM PST, paul swed wrote: Great story and like all things as you get to know them realities sink in. The great thing is getting past what you thought and appreciating that things work and have long lives. Have to say I always enjoyed reading the HP and Tek manuals because as an outsider you did learn. Granted I normally dug in deep because I end up with a $25 scope by the pound or other widget for $25. That said today what are schematics. You don't ever find them anymore nor technical write ups. Because you are not supposed to fix the gear. Not good for business. So I end up reverse engineering many things. Still a good feeling when whatever it is comes back to life. But back to HP those manual give great insights. I have picked up many manuals just out of reading interest. Thanks again Hugh. Paul WB8TSL On Sat, Feb 9, 2019 at 4:07 PM Adrian Godwin wrote: > The schematics are so good - easy to read, lots of context. Even some > off-board parts shown so you can see where the signal ends up. Notes about > the function and adjustment. You can learn a lot from them. Manuals were > worth having. > > So many of today's schematics are little more than a netlist : a bunch of > fragmented sections with no way to find how they link up (maybe net names > but you can't tell if they have 2 ends or several). Useless even for > troubleshooting, let alone education. > > > On Sat, Feb 9, 2019 at 6:08 PM Poul-Henning Kamp > wrote: > > > Hugh, > > > > I notice your design, like all other HP designs I have seen from > > that era, operates with a very high margin for low mains voltage. > > > > Do you happen to remember what HP's design criteria were for this ? > > > > -- > > 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@lists.febo.com > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
Before I worked for HP, I used to read HP manuals like they were textbooks. I was like Hugh in that I thought everything HP did must be great. So I decided to reverse engineer a 200 to 300 MHz VCO used in a 0 to 100 MHz spectrum analyzer plug in. The manual only gave an - number for the transistor, but I examined the circuit board and noticed that the transistor was labelled: 2N5179, a very ubiquitous RF transistor in those days. I thought I was being very clever to copy this VCO. Fast forward: it turned out that this VCO was one of the WORST VCO's ever designed. Terrible phase noise. Crime does not pay. I designed my own VCO that blew the doors off that one. Rick On 2/9/2019 1:55 PM, paul swed wrote: Have to say I always enjoyed reading the HP and Tek manuals because as an outsider you did learn. Granted I normally dug in deep because I end up ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
Great story and like all things as you get to know them realities sink in. The great thing is getting past what you thought and appreciating that things work and have long lives. Have to say I always enjoyed reading the HP and Tek manuals because as an outsider you did learn. Granted I normally dug in deep because I end up with a $25 scope by the pound or other widget for $25. That said today what are schematics. You don't ever find them anymore nor technical write ups. Because you are not supposed to fix the gear. Not good for business. So I end up reverse engineering many things. Still a good feeling when whatever it is comes back to life. But back to HP those manual give great insights. I have picked up many manuals just out of reading interest. Thanks again Hugh. Paul WB8TSL On Sat, Feb 9, 2019 at 4:07 PM Adrian Godwin wrote: > The schematics are so good - easy to read, lots of context. Even some > off-board parts shown so you can see where the signal ends up. Notes about > the function and adjustment. You can learn a lot from them. Manuals were > worth having. > > So many of today's schematics are little more than a netlist : a bunch of > fragmented sections with no way to find how they link up (maybe net names > but you can't tell if they have 2 ends or several). Useless even for > troubleshooting, let alone education. > > > On Sat, Feb 9, 2019 at 6:08 PM Poul-Henning Kamp > wrote: > > > Hugh, > > > > I notice your design, like all other HP designs I have seen from > > that era, operates with a very high margin for low mains voltage. > > > > Do you happen to remember what HP's design criteria were for this ? > > > > -- > > 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@lists.febo.com > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
The schematics are so good - easy to read, lots of context. Even some off-board parts shown so you can see where the signal ends up. Notes about the function and adjustment. You can learn a lot from them. Manuals were worth having. So many of today's schematics are little more than a netlist : a bunch of fragmented sections with no way to find how they link up (maybe net names but you can't tell if they have 2 ends or several). Useless even for troubleshooting, let alone education. On Sat, Feb 9, 2019 at 6:08 PM Poul-Henning Kamp wrote: > Hugh, > > I notice your design, like all other HP designs I have seen from > that era, operates with a very high margin for low mains voltage. > > Do you happen to remember what HP's design criteria were for this ? > > -- > 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@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP Stories: Battery Chargers, and a fading idolization of HP
Hugh, I notice your design, like all other HP designs I have seen from that era, operates with a very high margin for low mains voltage. Do you happen to remember what HP's design criteria were for this ? -- 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@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
