Klaus Kragelund <klauskvik@hotmail.com> wrote:> On Thursday, May 21, 2020 at 10:44:39 PM UTC+2, John Larkin wrote: >> On Thu, 21 May 2020 14:07:29 -0400, Phil Hobbs >> <pcdhSpamMeSenseless@electrooptical.net> wrote: >> >> >On 2020-05-21 13:38, John Larkin wrote: >> >> On Tue, 19 May 2020 09:55:39 -0400, Phil Hobbs >> >> <pcdhSpamMeSenseless@electrooptical.net> wrote: >> >> >> >>> On 2020-05-19 09:50, jlarkin@highlandsniptechnology.com wrote: >> >>>> On Tue, 19 May 2020 12:50:44 +0530, Pimpom <nobody@nowhere.com> wrote: >> >>>> >> >>>>> On 5/19/2020 9:31 AM, jlarkin@highlandsniptechnology.com wrote: >> >>>>>> On Mon, 18 May 2020 17:57:06 -0700 (PDT), >> >>>>>> bloggs.fredbloggs.fred@gmail.com wrote: >> >>>>>> >> >>>>>>> On Monday, May 18, 2020 at 7:41:34 PM UTC-4, John Larkin wrote: >> >>>>>>>> ST makes a nice little LDO, super-low dropout with an aux Vbias >> >>>>>>>> supply. Saves me from rolling my own with an opamp and a mosfet. >> >>>>>>>> >> >>>>>>>> It's an ST1L08. >> >>>>>>>> >> >>>>>>>> So why is the data sheet file en.DM00123507.pdf ? >> >>>>>>> >> >>>>>>> Who cares, it's a crappy regulator. And the lying bastards with their fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V. >> >>>>>> >> >>>>>> Lying? It's all over the data sheet. It's how they get the millivolts >> >>>>>> of dropout. I do that when I make my own super-LDOs, power an opamp >> >>>>>> from some higher voltage and over-drive an nfet follower down to >> >>>>>> milliohms of Rds-on. >> >>>>>> >> >>>>>>> The GND current at no load of 35uA, sucks , as does that showy 80dB PSRR at 100 Hz. Battery operation usually doesn't care a whole lot about PSRR. And the thermal impedance specs are so bad, you just try getting 800mA out of it with any kind voltage headroom without using a liquid nitrogen drip. >> >>>>>>> >> >>>>>> >> >>>>>> I'm dropping a switched 1.8 to 1.5. That's 0.3 volts. Times 800 mA >> >>>>>> would be 0.24 watts dissipated. Actually, I don't need that much >> >>>>>> current to run a couple DRAM chips. >> >>>>>> >> >>>>> >> >>>>> Not directly comparable to the ST1L08 but the Holtek HT75xx-1 >> >>>>> series is nice. Max Vin 30V, 100mA, 2.5uA ground current, 25mV >> >>>>> drop-out. 16 different fixed output voltages from 2.1V to 12V >> >>>>> with 3% tolerance. As usual with products originating in the >> >>>>> East, the datasheet is rather sparse about details, but I've used >> >>>>> them and they do what I want. >> >>>> >> >>>> Is it stable with low ESR caps? We use polymers or ceramics mostly. >> >>>> >> >>>> We need so many goofy voltages that we usually buy adjustable >> >>>> regulators for stock. The board that I'm doing now has a 24-channel >> >>>> analog mux to BIST the power supplies, using the dreadful Xilinx >> >>>> 1-volt XADC that's inside their FPGAs. Free and worth it. >> >>>> >> >>>>> >> >>>>>> You sure are in a bad mood lately. >> >>>>>> >> >>>>> I've noticed that lately with some regulars here, including a few >> >>>>> who normally exhibit decent manners. >> >>>> >> >>>> Well, some never show any sign of manners. They are repulsive but >> >>>> you've got to feel sorry for them, stuck being around themselves all >> >>>> day. >> >>>> >> >>>> There's a basically perfect -1 correlation between being obnoxious and >> >>>> designing electronics. >> >>> >> >>> Well, now that Jim Thompson is apparently no longer with us. :( >> >>> >> >>> He was a bit of a statistical outlier. >> >> >> >> He was crabby and dismissive of people not as smart as he was, and >> >> hostile to people that might have been smarter, but he was >> >> occasionally helpful, and had a sense of humor, and was very brave at >> >> the end. >> >> >> > >> >When he wasn't busy accusing peoples' wives of immoral behaviour, >> >threatening folks with lawsuits or bodily harm, or siccing the FBI on >> >some deserving individuals. ;) >> >> Gosh, nobody's perfect. >> >> > >> >He was probably nice enough in person--we collaborated a couple of times >> >but never met in person or even talked on the phone together. >> > >> >I agree that he had guts and seems to have died very well. >> >> I used a version of his clever CD ignition (without his permission) as >> a gain-switched laser driver. Nice circuit. >> > I talked to him a couple of times, one review on a design when I guess he was close to not being with us any more > > He did an ASIC gatedriver design for us, nice design, cheap like we like it > > Suddenly we did not hear from him again, so another ASIC designer took over at that point > > He did minimum dev cost design, using an old version of Pspice to simulate the design, and then had another designer lay out the chip > > Cheers > > KlausGot to ask here, if I didn't years ago. How much different in behavior are analog circuits layed out with discrete components from the final IC itself? Let's talk pre computer simulations. For example, microwave and RF boards are constructed different from audio circuit boards, but if you look at a schematic, it's just a bunch of discretes wired together.
why do they do this?
Started by ●May 18, 2020
Reply by ●May 23, 20202020-05-23
Reply by ●May 23, 20202020-05-23
John Larkin <jlarkin@highland_atwork_technology.com> wrote:> On Thu, 21 May 2020 04:38:47 +0000 (UTC), Cydrome Leader > <presence@MUNGEpanix.com> wrote: > >>John Larkin <jlarkin@highland_atwork_technology.com> wrote: >>> On Wed, 20 May 2020 14:07:53 -0700 (PDT), Michael Terrell >>> <terrell.michael.a@gmail.com> wrote: >>> >>>>On Wednesday, May 20, 2020 at 12:09:51 PM UTC-4, John Larkin wrote: >>>>> >>>>> In our system, if you know any drawing or product part number, you >>>>> automatically know all the related ones. >>>>> >>>>> We refer to people by their names >>>> >>>> >>>> Some boards and modules were used in multiple product lines, so your system wouldn't have worked at Microdyne. It was a different market, requiring different methods. For instance: The 700 and 1620-base models shared a lot of boards, and the front panel/embedded controller was also used in the custom system built for NOAA to control their 100 foot dishes that track their LEO birds. Each board or model had it's own base model number, and some had over 20 versions because customers wanted different options, Some of their first products were still in use 24/7 for over 30 years at NASA, tracking deep space satellites. They had never been turned off, or repaired. >>> >>> We reuse boards, and assemblies, in multiple prducts. If there are >>> different versions, each has its own dash number and associated BOM. >>> That's standard mil practice. >> >>do you have to relabel parts to give them the correct (for the end user) >>part number? Sometimes there's goofiness with OEMed parts and trying to >>re-order them. I've gotten parts with say a different brand printed on >>them. > > We mostly sell products that we design and build. About the only > things we sell unmodified are wall-warts and a few cables, and we do > give those our own part numbers. A customer orders a 12-volt wart as a > model J12, and it has internal stock number 726-2012, which in turn > has a list of qualified sources. > > We don't encourage people to repair our stuff themselves, but if they > do need a part, like a transformer or connector or something, we > generally give them one.I came across something terrible once while servicing an older machine. It was "standard" octal socket/DIN mount timers or temp controllers that had been tampered with by the manufacturer of the final product. The intent was to render the use of off the shelf replacements inoperable. It took some time to figure this out. Never seen a dick move like that before. I went ahead and un-fucked the rest of the parts and rewired the sockets to allow replacement of parts in the future. Sort of surprised they didn't wire a NC relay contact across the power supply terminals to be honest. I broke one of the controllers open to see why the new counterparts did not work. If a customer sounds qualified, do you ever give tips in troubleshooting/recalibration or anything like that?>>> In the aircraft business, xxxxx was a drawing and xxxxx-1 was a thing, >>> and xxxxx-2 was its mirror image thing. Odds and evens were mirrors, >>> like wings maybe, without requiring two drawings. We don't mirror >>> parts, so for us -1 and -2 are just assembly versions of some sort. >> >>Were there ever "funny" issues with mirror image parts, like the left part >>ended up with english thread fasteners or something dumb like that? > > I wonder if they tapped reverse threads!There should be callouts, but sometimes folks have to learn the hard way. I recently came some not-working test equipment that somebody tried on 208 volts instead of 120 volts. Guess they forgot about that fuse block voltage selector.>>>> Completed units had custom build list, per the contract and all the test data for a unit was stored long term. The ISO inspectors spent most of their time looking at the files, since a record for one unit could be a half inch thick. That was why I pushed to change the test procedures to streamline them.It reduced the paperwork by about 25%. Some were rewritten from scratch, because the designer had the steps out of order, wasting test time. You had to do the same step several times before they were updated. A test fixture I redesigned educed the test time from 7.5 hours to 18 minutes and gave a more repeatable result. I know that you dislike trimpots, but they were used to adjust gan in many circuits. Even with 1% resistors and capacitors, they were often out of spec since 14, 1% components were used per video filter. >>> >>> Most of our testing is automated now, and test reports get pushed up >>> to a server, as both PDF and JSON files. We can easily extract >>> statistics from the JSON files. >> >>How did this work say 20 or 30 years ago? > > No, test reports were paper and procedures were manual or much less > automated than now.Did anybody keep copies in filing cabinet or microfilm or someting weird like that?
Reply by ●May 23, 20202020-05-23
Michael Terrell <terrell.michael.a@gmail.com> wrote:> On Thursday, May 21, 2020 at 10:35:09 AM UTC-4, jla...@highlandsniptechnology.com wrote: >> On Thu, 21 May 2020 01:55:31 -0700 (PDT), Michael Terrell Wrote: >> > >> >We were just starting to automate testing, but that was almost 19 years ago. Documentation and board or model number matched the blank board, plus the BOM and test procedure for different versions but with over 20 modules in a unit, plus a separate plug in tuner for older models (depending on which microwave band) still complicated issues. Add that the company had been around since 1968 which was before most small businesses used computers, the system was deeply embedded in the daily operations. They had changed their part numbering system, once and it was a nightmare. Every BOM had to be rewritten, on a typewriter, then all old copies destroyed. >> > >> > On top of that, when they decided to close their original Rockville Maryland plant, the employees shredded every document in the vault, plus all working copies, leaving the engineers the task of reverse engineering the last complete units and to recreate the mountain of data. >> >> Some companies have a "configuration control" department, whose job is >> to control all the documents and their relationship, and make sure the >> right stuff gets manufactured and remembered. All documents have to be >> submitted to them. >> >> Makes sense; keeping this stuff organized is non-trivial, especially >> when mistakes can kill people. > > > We did a lot of work for NASA and NOAA. We supplied their 'Command Destruct Receivers. If one of those failed, a rocket could kill a lot of people.lol. Coded squelch? How are those things matched or activated between transmitter and reciver?
Reply by ●May 23, 20202020-05-23
Cydrome Leader <presence@MUNGEpanix.com> wrote in news:raaked$in1$2@reader1.panix.com:> Michael Terrell <terrell.michael.a@gmail.com> wrote: >> On Thursday, May 21, 2020 at 10:35:09 AM UTC-4, >> jla...@highlandsniptechnology.com wrote: >>> On Thu, 21 May 2020 01:55:31 -0700 (PDT), Michael Terrell Wrote: >>> > >>> >We were just starting to automate testing, but that was almost >>> >19 years ago. Documentation and board or model number matched >>> >the blank board, plus the BOM and test procedure for different >>> >versions but with over 20 modules in a unit, plus a separate >>> >plug in tuner for older models (depending on which microwave >>> >band) still complicated issues. Add that the company had been >>> >around since 1968 which was before most small businesses used >>> >computers, the system was deeply embedded in the daily >>> >operations. They had changed their part numbering system, once >>> >and it was a nightmare. Every BOM had to be rewritten, on a >>> >typewriter, then all old copies destroyed. >>> > >>> > On top of that, when they decided to close their original >>> > Rockville Maryland plant, the employees shredded every >>> > document in the vault, plus all working copies, leaving the >>> > engineers the task of reverse engineering the last complete >>> > units and to recreate the mountain of data. >>> >>> Some companies have a "configuration control" department, whose >>> job is to control all the documents and their relationship, and >>> make sure the right stuff gets manufactured and remembered. All >>> documents have to be submitted to them. >>> >>> Makes sense; keeping this stuff organized is non-trivial, >>> especially when mistakes can kill people. >> >> >> We did a lot of work for NASA and NOAA. We supplied their >> 'Command Destruct Receivers. If one of those failed, a rocket >> could kill a lot of people. > > lol. Coded squelch? How are those things matched or activated > between transmitter and reciver? >Document management standards are now ISO 9001 At least for any company with any brains and some contractors (The US Gov) require it.
Reply by ●May 23, 20202020-05-23
On Thursday, May 21, 2020 at 2:26:50 AM UTC-4, Phil Hobbs wrote:> On 2020-05-21 00:44, Cydrome Leader wrote: > > Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> On 2020-05-19 09:50, jlarkin@highlandsniptechnology.com wrote: > >>> On Tue, 19 May 2020 12:50:44 +0530, Pimpom <nobody@nowhere.com> wrote: > >>> > >>>> On 5/19/2020 9:31 AM, jlarkin@highlandsniptechnology.com wrote: > >>>>> On Mon, 18 May 2020 17:57:06 -0700 (PDT), > >>>>> bloggs.fredbloggs.fred@gmail.com wrote: > >>>>> > >>>>>> On Monday, May 18, 2020 at 7:41:34 PM UTC-4, John Larkin wrote: > >>>>>>> ST makes a nice little LDO, super-low dropout with an aux Vbias > >>>>>>> supply. Saves me from rolling my own with an opamp and a mosfet. > >>>>>>> > >>>>>>> It's an ST1L08. > >>>>>>> > >>>>>>> So why is the data sheet file en.DM00123507.pdf ? > >>>>>> > >>>>>> Who cares, it's a crappy regulator. And the lying bastards with their fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V. > >>>>> > >>>>> Lying? It's all over the data sheet. It's how they get the millivolts > >>>>> of dropout. I do that when I make my own super-LDOs, power an opamp > >>>>> from some higher voltage and over-drive an nfet follower down to > >>>>> milliohms of Rds-on. > >>>>> > >>>>>> The GND current at no load of 35uA, sucks , as does that showy 80dB PSRR at 100 Hz. Battery operation usually doesn't care a whole lot about PSRR. And the thermal impedance specs are so bad, you just try getting 800mA out of it with any kind voltage headroom without using a liquid nitrogen drip. > >>>>>> > >>>>> > >>>>> I'm dropping a switched 1.8 to 1.5. That's 0.3 volts. Times 800 mA > >>>>> would be 0.24 watts dissipated. Actually, I don't need that much > >>>>> current to run a couple DRAM chips. > >>>>> > >>>> > >>>> Not directly comparable to the ST1L08 but the Holtek HT75xx-1 > >>>> series is nice. Max Vin 30V, 100mA, 2.5uA ground current, 25mV > >>>> drop-out. 16 different fixed output voltages from 2.1V to 12V > >>>> with 3% tolerance. As usual with products originating in the > >>>> East, the datasheet is rather sparse about details, but I've used > >>>> them and they do what I want. > >>> > >>> Is it stable with low ESR caps? We use polymers or ceramics mostly. > >>> > >>> We need so many goofy voltages that we usually buy adjustable > >>> regulators for stock. The board that I'm doing now has a 24-channel > >>> analog mux to BIST the power supplies, using the dreadful Xilinx > >>> 1-volt XADC that's inside their FPGAs. Free and worth it. > >>> > >>>> > >>>>> You sure are in a bad mood lately. > >>>>> > >>>> I've noticed that lately with some regulars here, including a few > >>>> who normally exhibit decent manners. > >>> > >>> Well, some never show any sign of manners. They are repulsive but > >>> you've got to feel sorry for them, stuck being around themselves all > >>> day. > >>> > >>> There's a basically perfect -1 correlation between being obnoxious and > >>> designing electronics. > >> > >> Well, now that Jim Thompson is apparently no longer with us. :( > >> > >> He was a bit of a statistical outlier. > > > > Was that the guy who designed all the 2 digit LM series chips? What > > happened to him? > > > > He was more in the Motorola orbit back then, IIRC, but he was certainly > the most accomplished IC designer in the group. He disappeared a couple > of years ago, after having been diagnosed with early-stage pancreatic > cancer during tests for something else. He said that he thought he had > beaten it, but then just disappeared from the group. His website > subsequently disappeared as well. > > Various folks have looked for an obituary, but nothing turned up. (His > full name was James Elbert Thompson, and he lived most recently in Queen > Creek AZ.) He was a bit of a chingada but designed a lot of interesting > electronics and really helped keep the local leftists in check.That's a bit of a laugh. Suggesting that JT kept anyone in check with his delusional ranting is like suggesting Larkin tells the straight story of the coronavirus by his in depth analysis of the data and his knowledge of epidemiology. JT may have done interesting design work, but when it came to politics he was a raving maniac. -- Rick C. --- Get 1,000 miles of free Supercharging --- Tesla referral code - https://ts.la/richard11209
Reply by ●May 23, 20202020-05-23
On Saturday, May 23, 2020 at 5:32:38 PM UTC+10, Cydrome Leader wrote:> Klaus Kragelund <klauskvik@hotmail.com> wrote: > > On Thursday, May 21, 2020 at 10:44:39 PM UTC+2, John Larkin wrote: > >> On Thu, 21 May 2020 14:07:29 -0400, Phil Hobbs > >> <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> > >> >On 2020-05-21 13:38, John Larkin wrote: > >> >> On Tue, 19 May 2020 09:55:39 -0400, Phil Hobbs > >> >> <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> >> > >> >>> On 2020-05-19 09:50, jlarkin@highlandsniptechnology.com wrote: > >> >>>> On Tue, 19 May 2020 12:50:44 +0530, Pimpom <nobody@nowhere.com> wrote: > >> >>>> > >> >>>>> On 5/19/2020 9:31 AM, jlarkin@highlandsniptechnology.com wrote: > >> >>>>>> On Mon, 18 May 2020 17:57:06 -0700 (PDT), > >> >>>>>> bloggs.fredbloggs.fred@gmail.com wrote: > >> >>>>>> > >> >>>>>>> On Monday, May 18, 2020 at 7:41:34 PM UTC-4, John Larkin wrote: > >> >>>>>>>> ST makes a nice little LDO, super-low dropout with an aux Vbias > >> >>>>>>>> supply. Saves me from rolling my own with an opamp and a mosfet. > >> >>>>>>>> > >> >>>>>>>> It's an ST1L08. > >> >>>>>>>> > >> >>>>>>>> So why is the data sheet file en.DM00123507.pdf ? > >> >>>>>>> > >> >>>>>>> Who cares, it's a crappy regulator. And the lying bastards with their fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V. > >> >>>>>> > >> >>>>>> Lying? It's all over the data sheet. It's how they get the millivolts > >> >>>>>> of dropout. I do that when I make my own super-LDOs, power an opamp > >> >>>>>> from some higher voltage and over-drive an nfet follower down to > >> >>>>>> milliohms of Rds-on. > >> >>>>>> > >> >>>>>>> The GND current at no load of 35uA, sucks , as does that showy 80dB PSRR at 100 Hz. Battery operation usually doesn't care a whole lot about PSRR. And the thermal impedance specs are so bad, you just try getting 800mA out of it with any kind voltage headroom without using a liquid nitrogen drip. > >> >>>>>>> > >> >>>>>> > >> >>>>>> I'm dropping a switched 1.8 to 1.5. That's 0.3 volts. Times 800 mA > >> >>>>>> would be 0.24 watts dissipated. Actually, I don't need that much > >> >>>>>> current to run a couple DRAM chips. > >> >>>>>> > >> >>>>> > >> >>>>> Not directly comparable to the ST1L08 but the Holtek HT75xx-1 > >> >>>>> series is nice. Max Vin 30V, 100mA, 2.5uA ground current, 25mV > >> >>>>> drop-out. 16 different fixed output voltages from 2.1V to 12V > >> >>>>> with 3% tolerance. As usual with products originating in the > >> >>>>> East, the datasheet is rather sparse about details, but I've used > >> >>>>> them and they do what I want. > >> >>>> > >> >>>> Is it stable with low ESR caps? We use polymers or ceramics mostly. > >> >>>> > >> >>>> We need so many goofy voltages that we usually buy adjustable > >> >>>> regulators for stock. The board that I'm doing now has a 24-channel > >> >>>> analog mux to BIST the power supplies, using the dreadful Xilinx > >> >>>> 1-volt XADC that's inside their FPGAs. Free and worth it. > >> >>>> > >> >>>>> > >> >>>>>> You sure are in a bad mood lately. > >> >>>>>> > >> >>>>> I've noticed that lately with some regulars here, including a few > >> >>>>> who normally exhibit decent manners. > >> >>>> > >> >>>> Well, some never show any sign of manners. They are repulsive but > >> >>>> you've got to feel sorry for them, stuck being around themselves all > >> >>>> day. > >> >>>> > >> >>>> There's a basically perfect -1 correlation between being obnoxious and > >> >>>> designing electronics. > >> >>> > >> >>> Well, now that Jim Thompson is apparently no longer with us. :( > >> >>> > >> >>> He was a bit of a statistical outlier. > >> >> > >> >> He was crabby and dismissive of people not as smart as he was, and > >> >> hostile to people that might have been smarter, but he was > >> >> occasionally helpful, and had a sense of humor, and was very brave at > >> >> the end. > >> > > >> >When he wasn't busy accusing peoples' wives of immoral behaviour, > >> >threatening folks with lawsuits or bodily harm, or siccing the FBI on > >> >some deserving individuals. ;) > >> > >> Gosh, nobody's perfect.He was imperfect enough to look remarkably like a psychopath.> >> >He was probably nice enough in person--we collaborated a couple of times > >> >but never met in person or even talked on the phone together. > >> > > >> >I agree that he had guts and seems to have died very well. > >> > >> I used a version of his clever CD ignition (without his permission) as > >> a gain-switched laser driver. Nice circuit. > >> > > I talked to him a couple of times, one review on a design when I guess he was close to not being with us any more > > > > He did an ASIC gatedriver design for us, nice design, cheap like we like it > > > > Suddenly we did not hear from him again, so another ASIC designer took over at that point > > > > He did minimum dev cost design, using an old version of Pspice to simulate the design, and then had another designer lay out the chip > > Got to ask here, if I didn't years ago. How much different in behavior are > analog circuits laid out with discrete components from the final IC > itself?My impression is integrated circuit designs don't look much like discrete component designs. Lot's more current sources, and many fewer resistors for a start. At high frequencies, the fact that the connections are lot shorter (and less inductive) makes a big difference. Bob Widlar and Barry Gilbert were famously good at exploiting the advantages these sorts of difference offer.> Let's talk pre computer simulations. For example, microwave and RF > boards are constructed different from audio circuit boards, but if you > look at a schematic, it's just a bunch of discretes wired together.If you look at the printed circuit boards, microwave and RF boards are constructed with the critical connections laid out as constant impedance transmission lines routed over (or between) solid ground planes (mostly buried in multilayer boards). Buried ground planes do show up in some audio circuits - they do a good job of shielding sensitive bits from noise radiated from the higher current bits, and any digital signals running around - but you can get by without them. Looking at the schematic isn't all that educational - essentially it's a way of representing the net-list (which pins on which components are connected to which other pins). It leaves out stray capacitances, lead inductances, mutual inductances between leads, heat dissipation, component dimensions and the rest of the stuff that constrains printed circuit layout. Back when I was designing circuits, the schematic got passed to the drafting shop with several pages of notes on how it was going to have to be laid out. The good layout draftsmen didn't need much, but they weren't all good. Once a printed circuit manufacturer didn't like my board stack-up - they feared that the board would warp - and the draftsman okayed their version. A whole lot of constant impedance transmission ended up with with the wrong impedance. It took us a couple weeks to wake up. -- Bill Sloman, Sydney
Reply by ●May 23, 20202020-05-23
On Sat, 23 May 2020 07:45:26 +0000 (UTC), Cydrome Leader <presence@MUNGEpanix.com> wrote:>John Larkin <jlarkin@highland_atwork_technology.com> wrote: >> On Thu, 21 May 2020 04:38:47 +0000 (UTC), Cydrome Leader >> <presence@MUNGEpanix.com> wrote: >> >>>John Larkin <jlarkin@highland_atwork_technology.com> wrote: >>>> On Wed, 20 May 2020 14:07:53 -0700 (PDT), Michael Terrell >>>> <terrell.michael.a@gmail.com> wrote: >>>> >>>>>On Wednesday, May 20, 2020 at 12:09:51 PM UTC-4, John Larkin wrote: >>>>>> >>>>>> In our system, if you know any drawing or product part number, you >>>>>> automatically know all the related ones. >>>>>> >>>>>> We refer to people by their names >>>>> >>>>> >>>>> Some boards and modules were used in multiple product lines, so your system wouldn't have worked at Microdyne. It was a different market, requiring different methods. For instance: The 700 and 1620-base models shared a lot of boards, and the front panel/embedded controller was also used in the custom system built for NOAA to control their 100 foot dishes that track their LEO birds. Each board or model had it's own base model number, and some had over 20 versions because customers wanted different options, Some of their first products were still in use 24/7 for over 30 years at NASA, tracking deep space satellites. They had never been turned off, or repaired. >>>> >>>> We reuse boards, and assemblies, in multiple prducts. If there are >>>> different versions, each has its own dash number and associated BOM. >>>> That's standard mil practice. >>> >>>do you have to relabel parts to give them the correct (for the end user) >>>part number? Sometimes there's goofiness with OEMed parts and trying to >>>re-order them. I've gotten parts with say a different brand printed on >>>them. >> >> We mostly sell products that we design and build. About the only >> things we sell unmodified are wall-warts and a few cables, and we do >> give those our own part numbers. A customer orders a 12-volt wart as a >> model J12, and it has internal stock number 726-2012, which in turn >> has a list of qualified sources. >> >> We don't encourage people to repair our stuff themselves, but if they >> do need a part, like a transformer or connector or something, we >> generally give them one. > >I came across something terrible once while servicing an older machine. It >was "standard" octal socket/DIN mount timers or temp controllers that had >been tampered with by the manufacturer of the final product. The intent >was to render the use of off the shelf replacements inoperable. It took >some time to figure this out. Never seen a dick move like that before. I >went ahead and un-fucked the rest of the parts and rewired the sockets to >allow replacement of parts in the future. Sort of surprised they didn't >wire a NC relay contact across the power supply terminals to be honest. I >broke one of the controllers open to see why the new counterparts did not >work. > >If a customer sounds qualified, do you ever give tips in >troubleshooting/recalibration or anything like that?Anything they want, including schematics and advice and replacement loaners. But few customers can repair and recalibrate a product, because that generally needs a rack full of computer and test gear. We have sold a few test racks to customers who want to support the things themselves. It really annoys me when somebody charges 100x the real value for a replacement part that their design fried. Car dealerships sell low-end cars at a loss and make their profit on parts and service, like a $1000 door wiring harness. Kinda like ink cartriges.> >>>> In the aircraft business, xxxxx was a drawing and xxxxx-1 was a thing, >>>> and xxxxx-2 was its mirror image thing. Odds and evens were mirrors, >>>> like wings maybe, without requiring two drawings. We don't mirror >>>> parts, so for us -1 and -2 are just assembly versions of some sort. >>> >>>Were there ever "funny" issues with mirror image parts, like the left part >>>ended up with english thread fasteners or something dumb like that? >> >> I wonder if they tapped reverse threads! > >There should be callouts, but sometimes folks have to learn the hard way. >I recently came some not-working test equipment that somebody tried on 208 >volts instead of 120 volts. Guess they forgot about that fuse block >voltage selector.Ancient history! It's great that most gear now runs on most any AC or DC voltage.> >>>>> Completed units had custom build list, per the contract and all the test data for a unit was stored long term. The ISO inspectors spent most of their time looking at the files, since a record for one unit could be a half inch thick. That was why I pushed to change the test procedures to streamline them.It reduced the paperwork by about 25%. Some were rewritten from scratch, because the designer had the steps out of order, wasting test time. You had to do the same step several times before they were updated. A test fixture I redesigned educed the test time from 7.5 hours to 18 minutes and gave a more repeatable result. I know that you dislike trimpots, but they were used to adjust gan in many circuits. Even with 1% resistors and capacitors, they were often out of spec since 14, 1% components were used per video filter. >>>> >>>> Most of our testing is automated now, and test reports get pushed up >>>> to a server, as both PDF and JSON files. We can easily extract >>>> statistics from the JSON files. >>> >>>How did this work say 20 or 30 years ago? >> >> No, test reports were paper and procedures were manual or much less >> automated than now. > >Did anybody keep copies in filing cabinet or microfilm or someting weird >like that?The paper's all on file, and we rarely have to look it up. -- John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard
Reply by ●May 23, 20202020-05-23
On Saturday, May 23, 2020 at 11:11:31 AM UTC-4, John Larkin wrote:> > It really annoys me when somebody charges 100x the real value for a > replacement part that their design fried. Car dealerships sell low-end > cars at a loss and make their profit on parts and service, like a > $1000 door wiring harness. Kinda like ink cartriges.Or those tire pressure sensors. A $30 retail part that some places charge $2400+ to replace. All they have to do is break down the tire from the rim, and exchange the part. One failed on my Caravan before it was two years old, and my dad had one fail on a Ford pickup truck before it was six months old. I can buy a complete aftermarket system for under $20 that has the transponder in a metal valve cap. The OEM use the same receiver for the electronic key. The rest is in the slopware.
Reply by ●May 23, 20202020-05-23
Bill Sloman <bill.sloman@ieee.org> wrote:> On Saturday, May 23, 2020 at 5:32:38 PM UTC+10, Cydrome Leader wrote: >> Klaus Kragelund <klauskvik@hotmail.com> wrote: >> > On Thursday, May 21, 2020 at 10:44:39 PM UTC+2, John Larkin wrote: >> >> On Thu, 21 May 2020 14:07:29 -0400, Phil Hobbs >> >> <pcdhSpamMeSenseless@electrooptical.net> wrote: >> >> >> >> >On 2020-05-21 13:38, John Larkin wrote: >> >> >> On Tue, 19 May 2020 09:55:39 -0400, Phil Hobbs >> >> >> <pcdhSpamMeSenseless@electrooptical.net> wrote: >> >> >> >> >> >>> On 2020-05-19 09:50, jlarkin@highlandsniptechnology.com wrote: >> >> >>>> On Tue, 19 May 2020 12:50:44 +0530, Pimpom <nobody@nowhere.com> wrote: >> >> >>>> >> >> >>>>> On 5/19/2020 9:31 AM, jlarkin@highlandsniptechnology.com wrote: >> >> >>>>>> On Mon, 18 May 2020 17:57:06 -0700 (PDT), >> >> >>>>>> bloggs.fredbloggs.fred@gmail.com wrote: >> >> >>>>>> >> >> >>>>>>> On Monday, May 18, 2020 at 7:41:34 PM UTC-4, John Larkin wrote: >> >> >>>>>>>> ST makes a nice little LDO, super-low dropout with an aux Vbias >> >> >>>>>>>> supply. Saves me from rolling my own with an opamp and a mosfet. >> >> >>>>>>>> >> >> >>>>>>>> It's an ST1L08. >> >> >>>>>>>> >> >> >>>>>>>> So why is the data sheet file en.DM00123507.pdf ? >> >> >>>>>>> >> >> >>>>>>> Who cares, it's a crappy regulator. And the lying bastards with their fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V. >> >> >>>>>> >> >> >>>>>> Lying? It's all over the data sheet. It's how they get the millivolts >> >> >>>>>> of dropout. I do that when I make my own super-LDOs, power an opamp >> >> >>>>>> from some higher voltage and over-drive an nfet follower down to >> >> >>>>>> milliohms of Rds-on. >> >> >>>>>> >> >> >>>>>>> The GND current at no load of 35uA, sucks , as does that showy 80dB PSRR at 100 Hz. Battery operation usually doesn't care a whole lot about PSRR. And the thermal impedance specs are so bad, you just try getting 800mA out of it with any kind voltage headroom without using a liquid nitrogen drip. >> >> >>>>>>> >> >> >>>>>> >> >> >>>>>> I'm dropping a switched 1.8 to 1.5. That's 0.3 volts. Times 800 mA >> >> >>>>>> would be 0.24 watts dissipated. Actually, I don't need that much >> >> >>>>>> current to run a couple DRAM chips. >> >> >>>>>> >> >> >>>>> >> >> >>>>> Not directly comparable to the ST1L08 but the Holtek HT75xx-1 >> >> >>>>> series is nice. Max Vin 30V, 100mA, 2.5uA ground current, 25mV >> >> >>>>> drop-out. 16 different fixed output voltages from 2.1V to 12V >> >> >>>>> with 3% tolerance. As usual with products originating in the >> >> >>>>> East, the datasheet is rather sparse about details, but I've used >> >> >>>>> them and they do what I want. >> >> >>>> >> >> >>>> Is it stable with low ESR caps? We use polymers or ceramics mostly. >> >> >>>> >> >> >>>> We need so many goofy voltages that we usually buy adjustable >> >> >>>> regulators for stock. The board that I'm doing now has a 24-channel >> >> >>>> analog mux to BIST the power supplies, using the dreadful Xilinx >> >> >>>> 1-volt XADC that's inside their FPGAs. Free and worth it. >> >> >>>> >> >> >>>>> >> >> >>>>>> You sure are in a bad mood lately. >> >> >>>>>> >> >> >>>>> I've noticed that lately with some regulars here, including a few >> >> >>>>> who normally exhibit decent manners. >> >> >>>> >> >> >>>> Well, some never show any sign of manners. They are repulsive but >> >> >>>> you've got to feel sorry for them, stuck being around themselves all >> >> >>>> day. >> >> >>>> >> >> >>>> There's a basically perfect -1 correlation between being obnoxious and >> >> >>>> designing electronics. >> >> >>> >> >> >>> Well, now that Jim Thompson is apparently no longer with us. :( >> >> >>> >> >> >>> He was a bit of a statistical outlier. >> >> >> >> >> >> He was crabby and dismissive of people not as smart as he was, and >> >> >> hostile to people that might have been smarter, but he was >> >> >> occasionally helpful, and had a sense of humor, and was very brave at >> >> >> the end. >> >> > >> >> >When he wasn't busy accusing peoples' wives of immoral behaviour, >> >> >threatening folks with lawsuits or bodily harm, or siccing the FBI on >> >> >some deserving individuals. ;) >> >> >> >> Gosh, nobody's perfect. > > He was imperfect enough to look remarkably like a psychopath. > >> >> >He was probably nice enough in person--we collaborated a couple of times >> >> >but never met in person or even talked on the phone together. >> >> > >> >> >I agree that he had guts and seems to have died very well. >> >> >> >> I used a version of his clever CD ignition (without his permission) as >> >> a gain-switched laser driver. Nice circuit. >> >> >> > I talked to him a couple of times, one review on a design when I guess he was close to not being with us any more >> > >> > He did an ASIC gatedriver design for us, nice design, cheap like we like it >> > >> > Suddenly we did not hear from him again, so another ASIC designer took over at that point >> > >> > He did minimum dev cost design, using an old version of Pspice to simulate the design, and then had another designer lay out the chip >> >> Got to ask here, if I didn't years ago. How much different in behavior are >> analog circuits laid out with discrete components from the final IC >> itself? > > My impression is integrated circuit designs don't look much like discrete component designs. > > Lot's more current sources, and many fewer resistors for a start. At high frequencies, the fact that the connections are lot shorter (and less inductive) makes a big difference. Bob Widlar and Barry Gilbert were famously good at exploiting the advantages these sorts of difference offer. > >> Let's talk pre computer simulations. For example, microwave and RF >> boards are constructed different from audio circuit boards, but if you >> look at a schematic, it's just a bunch of discretes wired together. > > If you look at the printed circuit boards, microwave and RF boards are > constructed with the critical connections laid out as constant impedance > transmission lines routed over (or between) solid ground planes (mostly > buried in multilayer boards). Buried ground planes do show up in some > audio circuits - they do a good job of shielding sensitive bits from > noise radiated from the higher current bits, and any digital signals > running around - but you can get by without them. > > Looking at the schematic isn't all that educational - essentially it's a > way of representing the net-list (which pins on which components are > connected to which other pins). It leaves out stray capacitances, lead > inductances, mutual inductances between leads, heat dissipation, > component dimensions and the rest of the stuff that constrains printed > circuit layout.so how did they come up with designs that worked? Take the first op amps for example. The behavior of the silicon isn't going to match a breadboard with some parts on it. Was it just a completely iterative process back in the day to get anything to work?> Back when I was designing circuits, the schematic got passed to the > drafting shop with several pages of notes on how it was going to have to > be laid out. > > The good layout draftsmen didn't need much, but they weren't all good. > Once a printed circuit manufacturer didn't like my board stack-up - they > feared that the board would warp - and the draftsman okayed their > version. > > A whole lot of constant impedance transmission ended up with with the > wrong impedance. It took us a couple weeks to wake up.Was any of this salvagable, or was it on to rev b? Anyone have stories of most expensive screw ups with board design or assemble?
Reply by ●May 23, 20202020-05-23
jlarkin@highlandsniptechnology.com wrote:> On Sat, 23 May 2020 07:45:26 +0000 (UTC), Cydrome Leader > <presence@MUNGEpanix.com> wrote: > >>John Larkin <jlarkin@highland_atwork_technology.com> wrote: >>> On Thu, 21 May 2020 04:38:47 +0000 (UTC), Cydrome Leader >>> <presence@MUNGEpanix.com> wrote: >>> >>>>John Larkin <jlarkin@highland_atwork_technology.com> wrote: >>>>> On Wed, 20 May 2020 14:07:53 -0700 (PDT), Michael Terrell >>>>> <terrell.michael.a@gmail.com> wrote: >>>>> >>>>>>On Wednesday, May 20, 2020 at 12:09:51 PM UTC-4, John Larkin wrote: >>>>>>> >>>>>>> In our system, if you know any drawing or product part number, you >>>>>>> automatically know all the related ones. >>>>>>> >>>>>>> We refer to people by their names >>>>>> >>>>>> >>>>>> Some boards and modules were used in multiple product lines, so your system wouldn't have worked at Microdyne. It was a different market, requiring different methods. For instance: The 700 and 1620-base models shared a lot of boards, and the front panel/embedded controller was also used in the custom system built for NOAA to control their 100 foot dishes that track their LEO birds. Each board or model had it's own base model number, and some had over 20 versions because customers wanted different options, Some of their first products were still in use 24/7 for over 30 years at NASA, tracking deep space satellites. They had never been turned off, or repaired. >>>>> >>>>> We reuse boards, and assemblies, in multiple prducts. If there are >>>>> different versions, each has its own dash number and associated BOM. >>>>> That's standard mil practice. >>>> >>>>do you have to relabel parts to give them the correct (for the end user) >>>>part number? Sometimes there's goofiness with OEMed parts and trying to >>>>re-order them. I've gotten parts with say a different brand printed on >>>>them. >>> >>> We mostly sell products that we design and build. About the only >>> things we sell unmodified are wall-warts and a few cables, and we do >>> give those our own part numbers. A customer orders a 12-volt wart as a >>> model J12, and it has internal stock number 726-2012, which in turn >>> has a list of qualified sources. >>> >>> We don't encourage people to repair our stuff themselves, but if they >>> do need a part, like a transformer or connector or something, we >>> generally give them one. >> >>I came across something terrible once while servicing an older machine. It >>was "standard" octal socket/DIN mount timers or temp controllers that had >>been tampered with by the manufacturer of the final product. The intent >>was to render the use of off the shelf replacements inoperable. It took >>some time to figure this out. Never seen a dick move like that before. I >>went ahead and un-fucked the rest of the parts and rewired the sockets to >>allow replacement of parts in the future. Sort of surprised they didn't >>wire a NC relay contact across the power supply terminals to be honest. I >>broke one of the controllers open to see why the new counterparts did not >>work. >> >>If a customer sounds qualified, do you ever give tips in >>troubleshooting/recalibration or anything like that? > > Anything they want, including schematics and advice and replacement > loaners. But few customers can repair and recalibrate a product, > because that generally needs a rack full of computer and test gear. We > have sold a few test racks to customers who want to support the things > themselves. > > It really annoys me when somebody charges 100x the real value for a > replacement part that their design fried. Car dealerships sell low-end > cars at a loss and make their profit on parts and service, like a > $1000 door wiring harness. Kinda like ink cartriges.It's sort of sad wiring harnesses haven't been figured out yet. I was reading about some maker that used some sort of soybean based wired insulation that critters would eat up. Who the hell came up with compostable wire or whatever the heck it was supposed to be?>>>>> In the aircraft business, xxxxx was a drawing and xxxxx-1 was a thing, >>>>> and xxxxx-2 was its mirror image thing. Odds and evens were mirrors, >>>>> like wings maybe, without requiring two drawings. We don't mirror >>>>> parts, so for us -1 and -2 are just assembly versions of some sort. >>>> >>>>Were there ever "funny" issues with mirror image parts, like the left part >>>>ended up with english thread fasteners or something dumb like that? >>> >>> I wonder if they tapped reverse threads! >> >>There should be callouts, but sometimes folks have to learn the hard way. >>I recently came some not-working test equipment that somebody tried on 208 >>volts instead of 120 volts. Guess they forgot about that fuse block >>voltage selector. > > Ancient history! It's great that most gear now runs on most any AC or > DC voltage.yes and no. Most throw away type internal switching power supplies are not serviceable and it might be hard to find replacement down the road. I actually hit a roadblock with a plain old filament+isolation transformer. I don't recall the generic part #, but they were a dime a dozen 100 years ago, but not now and I can't find a suitable replacement, even if I mount the new transformer somewhere else in the chassis. Sort of annoying. May have to give in an call the manufacturer to see how much they want, assuming they have spares. The 6.3 winding voltage seems too high so I suspect shorted turns, but can't really confirm that easily.>>>>>> Completed units had custom build list, per the contract and all the test data for a unit was stored long term. The ISO inspectors spent most of their time looking at the files, since a record for one unit could be a half inch thick. That was why I pushed to change the test procedures to streamline them.It reduced the paperwork by about 25%. Some were rewritten from scratch, because the designer had the steps out of order, wasting test time. You had to do the same step several times before they were updated. A test fixture I redesigned educed the test time from 7.5 hours to 18 minutes and gave a more repeatable result. I know that you dislike trimpots, but they were used to adjust gan in many circuits. Even with 1% resistors and capacitors, they were often out of spec since 14, 1% components were used per video filter. >>>>> >>>>> Most of our testing is automated now, and test reports get pushed up >>>>> to a server, as both PDF and JSON files. We can easily extract >>>>> statistics from the JSON files. >>>> >>>>How did this work say 20 or 30 years ago? >>> >>> No, test reports were paper and procedures were manual or much less >>> automated than now. >> >>Did anybody keep copies in filing cabinet or microfilm or someting weird >>like that? > > > The paper's all on file, and we rarely have to look it up.
