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why do they do this?

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 whi ch microwave band) still complicated issues. Add that the company had been around since 1968 which was before most small businesses used computers, th e system was deeply embedded in the daily operations. They had changed thei r part numbering system, once and it was a nightmare. Every BOM had to be r ewritten, on a typewriter, then all old copies destroyed.

aryland 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.

We did a lot of work for NASA and NOAA. We supplied their 'Command Destr uct Receivers. If one of those failed, a rocket could kill a lot of people.

Reply to
Michael Terrell
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What's wrong with the microchip part? 1302 ? ~1ua gnd current

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Reply to
TTman

On the S1B moon rocket, there was one transistor that fired the destruct charge. It was the most tested and qualified transistor in history, and the only one on the rocket that was in a socket.

I designed some flight hardware for the first stage, but it was noncritical telemetry so only got the normal levels of QC paranoia.

We etched our own PC boards in the bathroom and got away with it.

--

John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 

  Claude Bernard
Reply to
jlarkin

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.

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John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com
Reply to
John Larkin

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 wonder if they tapped reverse threads!

No, test reports were paper and procedures were manual or much less automated than now.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com
Reply to
John Larkin

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. ;)

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.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com
Reply to
Phil Hobbs

Gosh, nobody's perfect.

I used a version of his clever CD ignition (without his permission) as a gain-switched laser driver. Nice circuit.

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John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com
Reply to
John Larkin

I have a mirror of the last version of his web site at .

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com
Reply to
Phil Hobbs

When I google it, it comes up as:

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Cheers

KLaus

Bytheway, funny video, google spelling:

formatting link

Reply to
Klaus Kragelund

After all that handling and abuse, it was probably among the least reliable, too. ;)

At IBM, if you needed to commit a safety violation to get your work done, savvy folks did it in their offices, not their labs. Nobody ever did a hazardous chemical audit of the offices for some reason. ;)

It was pretty tame stuff usually--my lab didn't have a fume hood, and I needed to be able to etch patterns into metallized PVDF. I kept a RadioShack bottle of FeCl2 juice in my office, which was across the hall from my lab, and shuttled some back and forth as necessary.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com
Reply to
Phil Hobbs

e dropout specs while conveniently omitting the fact that Vbias must be gre ater than Vout + 1.5V. 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 wh ole lot about PSRR. And the thermal impedance specs are so bad, you just tr y getting 800mA out of it with any kind voltage headroom without using a li quid nitrogen drip.

It's not crappy from my point of view

Why would you use a ultra low dropout LDO, and have high headroom for the i nput?

Cheers

Klaus

Reply to
Klaus Kragelund

e:

heir fake dropout specs while conveniently omitting the fact that Vbias mus t be greater than Vout + 1.5V.

lts

p

dB 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 800 mA out of it with any kind voltage headroom without using a liquid nitrogen drip.

nd

I talked to him a couple of times, one review on a design when I guess he w as 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

Klaus

Reply to
Klaus Kragelund

te:

ake dropout specs while conveniently omitting the fact that Vbias must be g reater than Vout + 1.5V. The GND current at no load of 35uA, sucks , as doe s 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.

input?

One reason might be power dissipation. If you have a switcher generating 1 .5 volts and you need 1.2 volts it can be cost effective to use a linear an d not much different in efficiency. Or you might not be able to draw power from the higher voltage. The bias input is the low operating current, not the larger regulated current.

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Reply to
Ricketty C

rote:

fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V. The GND current at no load of 35uA, sucks , as d oes 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 jus t try getting 800mA out of it with any kind voltage headroom without using a liquid nitrogen drip.

he input?

1.5 volts and you need 1.2 volts it can be cost effective to use a linear and not much different in efficiency. Or you might not be able to draw pow er from the higher voltage. The bias input is the low operating current, n ot the larger regulated current.

The rhetorical question was actually a response to Slomans post. His point was that is was a bad device due to limited use of the dropout voltage was high. But my point was, that then just don't use that device for high dropo ut. Might as well use a LM78xx variant then

Cheers

Klaus

Reply to
Klaus Kragelund

Studies showed that cheap plastic transistors were more reliable than super metal can burned-in JAN-TX parts.

Somebody here recommended the book Ignition!

formatting link

It's great fun, if you skip over the chemical equations.

--

John Larkin         Highland Technology, Inc 
picosecond timing   precision measurement  

jlarkin att highlandtechnology dott com 
http://www.highlandtechnology.com
Reply to
John Larkin

Am 22.05.20 um 02:52 schrieb John Larkin:

A friend of mine used to argue that there were so many resistors (then) in a color TV that the manufacturers could not afford bad ones or production had serious problems. He advocated Beyschlag, now part of Vishay.

With our ESA project, we did not have a choice. But then I'm not qualified to solder them in. I had to call the solder lady for work on flight hardware.

Cheers, Gerhard

Reply to
Gerhard Hoffmann

I did on this one. That little LDO is on there somewhere.

formatting link

The DRAM is just there for possible future use. It needs 1.5. The FPGA core needs 1.0. Aux is 1.8. Something else needs 1.2. All that from a

1.8v switcher.

Prime input is +48.

As people make fancy chips, we can quit doing stuff like home-brew LDOs, put more on a board, and move up the abstraction stack. It's still design.

--

John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 

  Claude Bernard
Reply to
jlarkin

Over here, MIL-HDBK-217 used to rule the roost in projects like that. I had one employer that tried it out, building satellite ground equipment for the first civilian DBS system in 1981-83.

Among other things, '217 predicted that reliability would improve if you removed all the protection circuitry from your design. It was an early precursor of Total Quality Management, ISO 9000, etc., and ignored actual recent data on component reliability in favour of some 'golden' data set from long ago, based on ridiculously flawed studies that assumed that all failures had an Arrhenius temperature dependence, that nothing was ever learned from past failures, yada yada.

Folks who knew how things actually worked left the protection circuitry in place, put in the paperwork, and (when necessary) gold-plated the BOM to hit the 'reliability' numbers. Fortunately I was able to move on and go to grad school instead.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com
Reply to
Phil Hobbs

Sorry, that's not where the interesting stuff links from. Should be

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
ElectroOptical Innovations LLC / Hobbs ElectroOptics 
Optics, Electro-optics, Photonics, Analog Electronics 
Briarcliff Manor NY 10510 

http://electrooptical.net 
http://hobbs-eo.com
Reply to
Phil Hobbs

This all sounds familiar now- the IC designer in AZ. I didn't realize he's been gone for years now.

Reply to
Cydrome Leader

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