HP 8012a...

[bitrex]

The HP 8082 uses ECL you can\'t get no mo, and looks like a PITA to repair:

<https://youtu.be/09zhUbJl37w>

Far as I can tell its slower smaller cousin the 8012a is all
discrete-on-card though, yeah? It looks that way from the service manual
but I haven\'t checked every thing.

<https://www.keysight.com/us/en/assets/9018-03164/user-manuals/9018-03164.pdf>

A 5ns rise time is still useful for a number of jobs, and I can get a
dodgy unit for next to nothing locally. I figure if I use it once a year
it might be worth trying to fix up if it doesn\'t require exotic parts.

 

[bitrex]

On 4/26/2022 11:18 AM, bitrex wrote:

The HP 8082 uses ECL you can\'t get no mo, and looks like a PITA to repair:

https://youtu.be/09zhUbJl37w

Far as I can tell its slower smaller cousin the 8012a is all
discrete-on-card though, yeah? It looks that way from the service manual
but I haven\'t checked every thing.

https://www.keysight.com/us/en/assets/9018-03164/user-manuals/9018-03164.pdf


A 5ns rise time is still useful for a number of jobs, and I can get a
dodgy unit for next to nothing locally. I figure if I use it once a year
it might be worth trying to fix up if it doesn\'t require exotic parts.

I don\'t think I own equipment fast enough to calibrate a refurbed 8082
anyway, even if it\'s not the ECL that\'s the problem

 

[server]

On Tue, 26 Apr 2022 11:28:55 -0400, bitrex <user@example.net> wrote:

On 4/26/2022 11:18 AM, bitrex wrote:
The HP 8082 uses ECL you can\'t get no mo, and looks like a PITA to repair:

https://youtu.be/09zhUbJl37w

Far as I can tell its slower smaller cousin the 8012a is all
discrete-on-card though, yeah? It looks that way from the service manual
but I haven\'t checked every thing.

https://www.keysight.com/us/en/assets/9018-03164/user-manuals/9018-03164.pdf


A 5ns rise time is still useful for a number of jobs, and I can get a
dodgy unit for next to nothing locally. I figure if I use it once a year
it might be worth trying to fix up if it doesn\'t require exotic parts.

I don\'t think I own equipment fast enough to calibrate a refurbed 8082
anyway, even if it\'s not the ECL that\'s the problem

I\'m thinking of doing a pulse generator. There are tons of cheap
TTL-type ones around, so it would have to be multi-channel and fast.



--

Anybody can count to one.

- Robert Widlar

 

[Phil Hobbs]

jlarkin@highlandsniptechnology.com wrote:

On Tue, 26 Apr 2022 11:28:55 -0400, bitrex <user@example.net> wrote:

On 4/26/2022 11:18 AM, bitrex wrote:
The HP 8082 uses ECL you can\'t get no mo, and looks like a PITA to repair:

https://youtu.be/09zhUbJl37w

Far as I can tell its slower smaller cousin the 8012a is all
discrete-on-card though, yeah? It looks that way from the service manual
but I haven\'t checked every thing.

https://www.keysight.com/us/en/assets/9018-03164/user-manuals/9018-03164.pdf


A 5ns rise time is still useful for a number of jobs, and I can get a
dodgy unit for next to nothing locally. I figure if I use it once a year
it might be worth trying to fix up if it doesn\'t require exotic parts.

I don\'t think I own equipment fast enough to calibrate a refurbed 8082
anyway, even if it\'s not the ECL that\'s the problem

I\'m thinking of doing a pulse generator. There are tons of cheap
TTL-type ones around, so it would have to be multi-channel and fast.

I generally use my P400 for that. Of course it\'s all synchronous to a
single T0 channel, so it\'s completely useless for building the
asynchronous chain-of-monostable hairballs so beloved of grad students
of yore.

I have an HP 8013B, which more or less works but is nothing special.

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

 

[Phil Hobbs]

bitrex wrote:

On 4/26/2022 11:18 AM, bitrex wrote:
The HP 8082 uses ECL you can\'t get no mo, and looks like a PITA to
repair:

https://youtu.be/09zhUbJl37w

Far as I can tell its slower smaller cousin the 8012a is all
discrete-on-card though, yeah? It looks that way from the service
manual but I haven\'t checked every thing.

https://www.keysight.com/us/en/assets/9018-03164/user-manuals/9018-03164.pdf


A 5ns rise time is still useful for a number of jobs, and I can get a
dodgy unit for next to nothing locally. I figure if I use it once a
year it might be worth trying to fix up if it doesn\'t require exotic
parts.

I don\'t think I own equipment fast enough to calibrate a refurbed 8082
anyway, even if it\'s not the ECL that\'s the problem

Well, there\'s your problem. You can get a TDS 694C for a couple of
grand, and I might even kick in a trigger ASIC from my secret stash.

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

 

[Phil Hobbs]

Phil Hobbs wrote:

jlarkin@highlandsniptechnology.com wrote:
On Tue, 26 Apr 2022 11:28:55 -0400, bitrex <user@example.net> wrote:

On 4/26/2022 11:18 AM, bitrex wrote:
The HP 8082 uses ECL you can\'t get no mo, and looks like a PITA to
repair:

https://youtu.be/09zhUbJl37w

Far as I can tell its slower smaller cousin the 8012a is all
discrete-on-card though, yeah? It looks that way from the service
manual
but I haven\'t checked every thing.

https://www.keysight.com/us/en/assets/9018-03164/user-manuals/9018-03164.pdf



A 5ns rise time is still useful for a number of jobs, and I can get a
dodgy unit for next to nothing locally. I figure if I use it once a
year
it might be worth trying to fix up if it doesn\'t require exotic parts.

I don\'t think I own equipment fast enough to calibrate a refurbed 8082
anyway, even if it\'s not the ECL that\'s the problem

I\'m thinking of doing a pulse generator. There are tons of cheap
TTL-type ones around, so it would have to be multi-channel and fast.


I generally use my P400 for that.  Of course it\'s all synchronous to a
single T0 channel, so it\'s completely useless for building the
asynchronous chain-of-monostable hairballs so beloved of grad students
of yore.

I should add that one proposal for our snazzy new time stretcher APD
array chip was to use a 64 x 64 array of linear-mode APDs, with 25 T/Hs
each, with the track-holds timed using a half-monostable each.

IOW, as I pointed out, our chip would have had _over a hundred thousand
one-shots_ doing the timing. (O tempora! O mores!)

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

 

[bitrex]

On 4/26/2022 12:50 PM, Phil Hobbs wrote:

bitrex wrote:
On 4/26/2022 11:18 AM, bitrex wrote:
The HP 8082 uses ECL you can\'t get no mo, and looks like a PITA to
repair:

https://youtu.be/09zhUbJl37w

Far as I can tell its slower smaller cousin the 8012a is all
discrete-on-card though, yeah? It looks that way from the service
manual but I haven\'t checked every thing.

https://www.keysight.com/us/en/assets/9018-03164/user-manuals/9018-03164.pdf


A 5ns rise time is still useful for a number of jobs, and I can get a
dodgy unit for next to nothing locally. I figure if I use it once a
year it might be worth trying to fix up if it doesn\'t require exotic
parts.

I don\'t think I own equipment fast enough to calibrate a refurbed 8082
anyway, even if it\'s not the ECL that\'s the problem

Well, there\'s your problem.  You can get a TDS 694C for a couple of
grand, and I might even kick in a trigger ASIC from my secret stash.

Cheers

Phil Hobbs

It\'s a lovely scope but a few other items are going to take priority
this spring (cleaning) like an Agilent or similar multi-output PSU,
bench DMM, and LCR meter/impedance analyzer-thing (not quite sure what
to pick there and am open to suggestions), I\'ve solidly outgrown my
hand-held DMMs and China-special bench PSUs.

But a 8012a in unknown condition for $25 sure is tempting.

My girlfriend picked me up a nice present while she was looking for
thrift store clothing bargains, a 1987 hardbound HP product lineup guide
in mint condition, $3.99. Odd thing to find at a thrift store maybe but
this is the heart of what used to be DEC & Wang etc. country near Rte
128, maybe someone was cleaning out their closet also.

 

[bitrex]

On 4/26/2022 12:50 PM, Phil Hobbs wrote:

bitrex wrote:
On 4/26/2022 11:18 AM, bitrex wrote:
The HP 8082 uses ECL you can\'t get no mo, and looks like a PITA to
repair:

https://youtu.be/09zhUbJl37w

Far as I can tell its slower smaller cousin the 8012a is all
discrete-on-card though, yeah? It looks that way from the service
manual but I haven\'t checked every thing.

https://www.keysight.com/us/en/assets/9018-03164/user-manuals/9018-03164.pdf


A 5ns rise time is still useful for a number of jobs, and I can get a
dodgy unit for next to nothing locally. I figure if I use it once a
year it might be worth trying to fix up if it doesn\'t require exotic
parts.

I don\'t think I own equipment fast enough to calibrate a refurbed 8082
anyway, even if it\'s not the ECL that\'s the problem

Well, there\'s your problem.  You can get a TDS 694C for a couple of
grand, and I might even kick in a trigger ASIC from my secret stash.

Cheers

Phil Hobbs

The service manual seems to say you need a 100 MHz pulse generator like
the 8007a to calibrate an 8082a. Seems like a Dear Liza kind of situation

 

[bitrex]

On 4/26/2022 3:16 PM, bitrex wrote:

On 4/26/2022 12:50 PM, Phil Hobbs wrote:
bitrex wrote:
On 4/26/2022 11:18 AM, bitrex wrote:
The HP 8082 uses ECL you can\'t get no mo, and looks like a PITA to
repair:

https://youtu.be/09zhUbJl37w

Far as I can tell its slower smaller cousin the 8012a is all
discrete-on-card though, yeah? It looks that way from the service
manual but I haven\'t checked every thing.

https://www.keysight.com/us/en/assets/9018-03164/user-manuals/9018-03164.pdf


A 5ns rise time is still useful for a number of jobs, and I can get
a dodgy unit for next to nothing locally. I figure if I use it once
a year it might be worth trying to fix up if it doesn\'t require
exotic parts.

I don\'t think I own equipment fast enough to calibrate a refurbed
8082 anyway, even if it\'s not the ECL that\'s the problem

Well, there\'s your problem.  You can get a TDS 694C for a couple of
grand, and I might even kick in a trigger ASIC from my secret stash.

Cheers

Phil Hobbs


The service manual seems to say you need a 100 MHz pulse generator like
the 8007a to calibrate an 8082a. Seems like a Dear Liza kind of situation

Er, to calibrate the 8012a, rather

 

[Don Y]

On 4/26/2022 8:28 AM, bitrex wrote:

On 4/26/2022 11:18 AM, bitrex wrote:
The HP 8082 uses ECL you can\'t get no mo, and looks like a PITA to repair:

https://youtu.be/09zhUbJl37w

Far as I can tell its slower smaller cousin the 8012a is all discrete-on-card
though, yeah? It looks that way from the service manual but I haven\'t checked
every thing.

https://www.keysight.com/us/en/assets/9018-03164/user-manuals/9018-03164.pdf

A 5ns rise time is still useful for a number of jobs, and I can get a dodgy
unit for next to nothing locally. I figure if I use it once a year it might
be worth trying to fix up if it doesn\'t require exotic parts.

You can often pick up used kit from local tech firms, universities (excellent
source of kit as they often dump everything they purchased for a GRANT project
when the grant is over), etc. Some firms just contract disposal of their kit
to a firm; others sell at auction (which may or may not be \"public\"). Knowing
folks at these places is a great way to get the inside track...

I don\'t think I own equipment fast enough to calibrate a refurbed 8082 anyway,
even if it\'s not the ECL that\'s the problem

Yeah, I rescued an HP 3458A many years ago. After the initial \"pride of
rescueship\" (v \"ownership\") wore off, I realized it was just an oversized
*4* digit DVM given that I never needed more accuracy/precision than that!
And, surely wasn\'t going to PAY to have it calibrated to 8+ digits!

(here, bench space is far more precious than quality of kit!)

 

[server]

On Tue, 26 Apr 2022 12:47:15 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

jlarkin@highlandsniptechnology.com wrote:
On Tue, 26 Apr 2022 11:28:55 -0400, bitrex <user@example.net> wrote:

On 4/26/2022 11:18 AM, bitrex wrote:
The HP 8082 uses ECL you can\'t get no mo, and looks like a PITA to repair:

https://youtu.be/09zhUbJl37w

Far as I can tell its slower smaller cousin the 8012a is all
discrete-on-card though, yeah? It looks that way from the service manual
but I haven\'t checked every thing.

https://www.keysight.com/us/en/assets/9018-03164/user-manuals/9018-03164.pdf


A 5ns rise time is still useful for a number of jobs, and I can get a
dodgy unit for next to nothing locally. I figure if I use it once a year
it might be worth trying to fix up if it doesn\'t require exotic parts.

I don\'t think I own equipment fast enough to calibrate a refurbed 8082
anyway, even if it\'s not the ECL that\'s the problem

I\'m thinking of doing a pulse generator. There are tons of cheap
TTL-type ones around, so it would have to be multi-channel and fast.


I generally use my P400 for that. Of course it\'s all synchronous to a
single T0 channel, so it\'s completely useless for building the
asynchronous chain-of-monostable hairballs so beloved of grad students
of yore.

Reminds me, I should send you a P500 when we have some to spare. It
has the 25 v p-p GaN output stage, super-clean.



--

Anybody can count to one.

- Robert Widlar

 

[bitrex]

On 4/26/2022 9:49 PM, Don Y wrote:

On 4/26/2022 8:28 AM, bitrex wrote:
On 4/26/2022 11:18 AM, bitrex wrote:
The HP 8082 uses ECL you can\'t get no mo, and looks like a PITA to
repair:

https://youtu.be/09zhUbJl37w

Far as I can tell its slower smaller cousin the 8012a is all
discrete-on-card though, yeah? It looks that way from the service
manual but I haven\'t checked every thing.

https://www.keysight.com/us/en/assets/9018-03164/user-manuals/9018-03164.pdf


A 5ns rise time is still useful for a number of jobs, and I can get a
dodgy unit for next to nothing locally. I figure if I use it once a
year it might be worth trying to fix up if it doesn\'t require exotic
parts.

You can often pick up used kit from local tech firms, universities
(excellent
source of kit as they often dump everything they purchased for a GRANT
project
when the grant is over), etc.  Some firms just contract disposal of
their kit
to a firm; others sell at auction (which may or may not be \"public\").
Knowing
folks at these places is a great way to get the inside track...

There is a re-seller like that near me with several dozen \"tested\"
3478As bench DMMs available for $150 per (better test the AC section
though as it uses an unobtaninum part) and another place will calibrate
it for $50.

<https://youtu.be/9v6OksEFqpA>

I think I\'ll pick up a couple I used them in college & they\'re still
nice meters.

I don\'t think I own equipment fast enough to calibrate a refurbed 8082
anyway, even if it\'s not the ECL that\'s the problem

Yeah, I rescued an HP 3458A many years ago.  After the initial \"pride of
rescueship\" (v \"ownership\") wore off, I realized it was just an oversized
*4* digit DVM given that I never needed more accuracy/precision than that!
And, surely wasn\'t going to PAY to have it calibrated to 8+ digits!

(here, bench space is far more precious than quality of kit!)

Going off BW * tr = 0.34 as the fastest edge a DSO can even assign a
sample to, much less measure the rise time of accurately, I figure a 100
MHz scope is too sluggish to calibrate a 5ns pulser on its fastest
setting. /shrug

 

[Don Y]

On 4/26/2022 7:59 PM, bitrex wrote:

You can often pick up used kit from local tech firms, universities (excellent
source of kit as they often dump everything they purchased for a GRANT project
when the grant is over), etc. Some firms just contract disposal of their kit
to a firm; others sell at auction (which may or may not be \"public\"). Knowing
folks at these places is a great way to get the inside track...

There is a re-seller like that near me with several dozen \"tested\" 3478As bench
DMMs available for $150 per (better test the AC section though as it uses an
unobtaninum part) and another place will calibrate it for $50.

Resellers increase the price but usually don\'t add much \"value\". You want
to find the guy *he* buys from (usually someone at ABC Tech Corporation).

I think I\'ll pick up a couple I used them in college & they\'re still nice meters.

I don\'t think I own equipment fast enough to calibrate a refurbed 8082
anyway, even if it\'s not the ECL that\'s the problem

Yeah, I rescued an HP 3458A many years ago. After the initial \"pride of
rescueship\" (v \"ownership\") wore off, I realized it was just an oversized
*4* digit DVM given that I never needed more accuracy/precision than that!
And, surely wasn\'t going to PAY to have it calibrated to 8+ digits!

(here, bench space is far more precious than quality of kit!)

Going off BW * tr = 0.34 as the fastest edge a DSO can even assign a sample to,
much less measure the rise time of accurately, I figure a 100 MHz scope is too
sluggish to calibrate a 5ns pulser on its fastest setting. /shrug

Most of the products I\'ve designed have intentionally NOT required close
tolerances on anything. That adds cost -- in parts or calibration labor.
So, we design products that rely on other means to make sense of their
observations (ratiometric or other \"self calibration\" tricks).

[It\'s not uncommon to have manufacturing tolerances of -60%, +300%. Easy to
accommodate if you are smart about it.]

 

[Chris Jones]

On 27/04/2022 12:59, bitrex wrote:

On 4/26/2022 9:49 PM, Don Y wrote:
On 4/26/2022 8:28 AM, bitrex wrote:
On 4/26/2022 11:18 AM, bitrex wrote:
The HP 8082 uses ECL you can\'t get no mo, and looks like a PITA to
repair:

https://youtu.be/09zhUbJl37w

Far as I can tell its slower smaller cousin the 8012a is all
discrete-on-card though, yeah? It looks that way from the service
manual but I haven\'t checked every thing.

https://www.keysight.com/us/en/assets/9018-03164/user-manuals/9018-03164.pdf


A 5ns rise time is still useful for a number of jobs, and I can get
a dodgy unit for next to nothing locally. I figure if I use it once
a year it might be worth trying to fix up if it doesn\'t require
exotic parts.

You can often pick up used kit from local tech firms, universities
(excellent
source of kit as they often dump everything they purchased for a GRANT
project
when the grant is over), etc.  Some firms just contract disposal of
their kit
to a firm; others sell at auction (which may or may not be \"public\").

Around here it goes in a dumpster. Recently found a working TEK468 in
nearly perfect condition, with probes and everything. I don\'t see a lot
of it because it gets covered by the next layer, or it gets rained on,
or smashed by the next thing chucked in, or I just don\'t have the space.

Knowing
folks at these places is a great way to get the inside track...


There is a re-seller like that near me with several dozen \"tested\"
3478As bench DMMs available for $150 per (better test the AC section
though as it uses an unobtaninum part) and another place will calibrate
it for $50.

https://youtu.be/9v6OksEFqpA

I think I\'ll pick up a couple I used them in college & they\'re still
nice meters.

If you want to back up the SRAM calibration constants from a HP3478A
before the battery goes flat and loses it, there is now a project to
make a USB-GPIB interface with an Arduino:

https://github.com/Twilight-Logic/AR488

PCB to go with it:
https://oshpark.com/shared_projects/yfUOmUzA

Arduino clone that fits the PCB:
https://core-electronics.com.au/pro-micro-5v-16mhz.html

Needed drivers from the sparkfun website to suit that board:

https://learn.sparkfun.com/tutorials/pro-micro--fio-v3-hookup-guide/installing-windows

I don\'t normally use arduino stuff so that took a while to get working,
and only recent versions of the arduino IDE would compile it.

This software makes it easy to backup the SRAM contents using the AR488
GPIB adapter, and it allows you to tweak the offsets and gains and
re-generate a good checksum too, though I haven\'t tried it yet:

https://mesterhome.com/gpibsw/hp3478a/index.html

 

[Anthony William Sloman]

On Wednesday, April 27, 2022 at 1:44:33 PM UTC+10, Don Y wrote:

On 4/26/2022 7:59 PM, bitrex wrote:
You can often pick up used kit from local tech firms, universities (excellent
source of kit as they often dump everything they purchased for a GRANT project
when the grant is over), etc. Some firms just contract disposal of their kit
to a firm; others sell at auction (which may or may not be \"public\"). Knowing
folks at these places is a great way to get the inside track...

There is a re-seller like that near me with several dozen \"tested\" 3478As bench
DMMs available for $150 per (better test the AC section though as it uses an
unobtaninum part) and another place will calibrate it for $50.
Resellers increase the price but usually don\'t add much \"value\". You want
to find the guy *he* buys from (usually someone at ABC Tech Corporation).
I think I\'ll pick up a couple I used them in college & they\'re still nice meters.

I don\'t think I own equipment fast enough to calibrate a refurbed 8082
anyway, even if it\'s not the ECL that\'s the problem

Yeah, I rescued an HP 3458A many years ago. After the initial \"pride of
rescueship\" (v \"ownership\") wore off, I realized it was just an oversized
*4* digit DVM given that I never needed more accuracy/precision than that!
And, surely wasn\'t going to PAY to have it calibrated to 8+ digits!

(here, bench space is far more precious than quality of kit!)

Going off BW * tr = 0.34 as the fastest edge a DSO can even assign a sample to,
much less measure the rise time of accurately, I figure a 100 MHz scope is too
sluggish to calibrate a 5ns pulser on its fastest setting. /shrug
Most of the products I\'ve designed have intentionally NOT required close
tolerances on anything. That adds cost -- in parts or calibration labor.
So, we design products that rely on other means to make sense of their
observations (ratiometric or other \"self calibration\" tricks).

[It\'s not uncommon to have manufacturing tolerances of -60%, +300%. Easy to
accommodate if you are smart about it.]

There are precise parts around, and some that can be made very precise with nothing more than careful assembly.

The Thompson-Lampard calculable capacitor is the poster-child for that approach.

https://aapt.scitation.org/doi/10.1119/1.19203

It\'s usually used with a laser interferometer to get the length exactly right.

At a more mundane level, a ratio transformer can be wound by hand to give 0.1ppm ratio accuracy. A 1:1 bifilar wound inductive divider can be accurate to one part per billion.

I\'ve not seen anybody use Litz wire to make a ratio transformer, which would probably work better than the merely twisted bundles of wire use in regular ration transformers.

It\'s never all that easy to get rid of all the potential errors, and it\'s lot safer to just buy precise parts when you can.

--
Bill Sloman, Sydney

 

[Don Y]

On 4/26/2022 9:35 PM, Chris Jones wrote:

On 27/04/2022 12:59, bitrex wrote:
On 4/26/2022 9:49 PM, Don Y wrote:
On 4/26/2022 8:28 AM, bitrex wrote:
On 4/26/2022 11:18 AM, bitrex wrote:
The HP 8082 uses ECL you can\'t get no mo, and looks like a PITA to repair:

https://youtu.be/09zhUbJl37w

Far as I can tell its slower smaller cousin the 8012a is all
discrete-on-card though, yeah? It looks that way from the service manual
but I haven\'t checked every thing.

https://www.keysight.com/us/en/assets/9018-03164/user-manuals/9018-03164.pdf


A 5ns rise time is still useful for a number of jobs, and I can get a
dodgy unit for next to nothing locally. I figure if I use it once a year
it might be worth trying to fix up if it doesn\'t require exotic parts.

You can often pick up used kit from local tech firms, universities (excellent
source of kit as they often dump everything they purchased for a GRANT project
when the grant is over), etc. Some firms just contract disposal of their kit
to a firm; others sell at auction (which may or may not be \"public\").

Around here it goes in a dumpster. Recently found a working TEK468 in nearly
perfect condition, with probes and everything. I don\'t see a lot of it because
it gets covered by the next layer, or it gets rained on, or smashed by the next
thing chucked in, or I just don\'t have the space.

This -------------------------^^^^^^^^^^^^^^^^^^^^^ It\'s amazing how easily
you can accumulate \"stuph\"! Then, look back and say \"Why the hell do I
HAVE all of these things?? When was the last time I actually *used* them??!\"

Here, it is considered hazardous waste (eWaste). A private individual can
likely get away with tossing the occasional piece into their \"weekly trash
pickup\". The \"trash-man\" watches the contents of your barrel as it is
emptied into the truck (hydraulic lift). So, you hope he\'s not a stickler
*or* hope he can\'t recognize certain bits of kit. CRTs are almost impossible
to sneak past them!

But, businesses face more scrutiny -- and have larger volumes involved (and
usually contract out their trash removal so the trash guy would potentially be
screwed if found \"misbehaving\")

If you can claim them to be reused/refurbished/repurposed/recycled, then
there are many nonprofit groups who will accept them as donations (i.e.,
tax write-off to donor) and dispose of them more suitably (refurbish
and find them new homes or dismantle and recycle for component parts).
Groups, here, probably process ~5000+ PCs annually from such corporate
donors. (I triage ~2000 units in a normal year)

There is often some risk with this approach as the donor may want to
slip some \"hard to recycle\" items in with the \"donation\" (I\'ve had
to deal with medical devices using \"odd\"/dubious solutions, narcotics
like morphine sulphate, hypodermics, *used* suture kits, etc.).

Universities tend to opt for auctions to dispose of their \"trash\" (a
friend is fond of pointing out \"You\'re PAYING for their TRASH!!!\").
The same sort of issues can apply (I once was interested in a very nice
\"lot\" -- only to notice a 10 pound jar of mercury buried in the pile:
\"Responsibility for proper disposal of the items lies entirely with the
purchaser\")

OTOH, you can often find NIB items that simply didn\'t get unpacked or
used, as intended, before being discarded. (most of my larger UPSs
came to me via this route... 2KVA-5KVA with functional batteries!)

Knowing
folks at these places is a great way to get the inside track...

There is a re-seller like that near me with several dozen \"tested\" 3478As
bench DMMs available for $150 per (better test the AC section though as it
uses an unobtaninum part) and another place will calibrate it for $50.

https://youtu.be/9v6OksEFqpA

I think I\'ll pick up a couple I used them in college & they\'re still nice
meters.

If you want to back up the SRAM calibration constants from a HP3478A before the
battery goes flat and loses it, there is now a project to make a USB-GPIB
interface with an Arduino:

If it\'s an integrated \"BBSRAM module\", you can likely just remove it and
read it as a ROM (I have had to do this on many old bits of Sun kit).

https://github.com/Twilight-Logic/AR488

PCB to go with it:
https://oshpark.com/shared_projects/yfUOmUzA

Arduino clone that fits the PCB:
https://core-electronics.com.au/pro-micro-5v-16mhz.html

Needed drivers from the sparkfun website to suit that board:

https://learn.sparkfun.com/tutorials/pro-micro--fio-v3-hookup-guide/installing-windows

I don\'t normally use arduino stuff so that took a while to get working, and
only recent versions of the arduino IDE would compile it.

This software makes it easy to backup the SRAM contents using the AR488 GPIB
adapter, and it allows you to tweak the offsets and gains and re-generate a
good checksum too, though I haven\'t tried it yet:

https://mesterhome.com/gpibsw/hp3478a/index.html

 

[Phil Hobbs]

Don Y wrote:

On 4/26/2022 7:59 PM, bitrex wrote:
You can often pick up used kit from local tech firms, universities
(excellent
source of kit as they often dump everything they purchased for a
GRANT project
when the grant is over), etc.  Some firms just contract disposal of
their kit
to a firm; others sell at auction (which may or may not be \"public\").
Knowing
folks at these places is a great way to get the inside track...

There is a re-seller like that near me with several dozen \"tested\"
3478As bench DMMs available for $150 per (better test the AC section
though as it uses an unobtaninum part) and another place will
calibrate it for $50.

Resellers increase the price but usually don\'t add much \"value\".  You want
to find the guy *he* buys from (usually someone at ABC Tech Corporation).

I think I\'ll pick up a couple I used them in college & they\'re still
nice meters.

I don\'t think I own equipment fast enough to calibrate a refurbed
8082 anyway, even if it\'s not the ECL that\'s the problem

Yeah, I rescued an HP 3458A many years ago.  After the initial \"pride of
rescueship\" (v \"ownership\") wore off, I realized it was just an
oversized
*4* digit DVM given that I never needed more accuracy/precision than
that!
And, surely wasn\'t going to PAY to have it calibrated to 8+ digits!

(here, bench space is far more precious than quality of kit!)

Going off BW * tr = 0.34 as the fastest edge a DSO can even assign a
sample to, much less measure the rise time of accurately, I figure a
100 MHz scope is too sluggish to calibrate a 5ns pulser on its fastest
setting. /shrug

Most of the products I\'ve designed have intentionally NOT required close
tolerances on anything.  That adds cost -- in parts or calibration labor.
So, we design products that rely on other means to make sense of their
observations (ratiometric or other \"self calibration\" tricks).

[It\'s not uncommon to have manufacturing tolerances of -60%, +300%.
Easy to
accommodate if you are smart about it.]

A pity you didn\'t just replace NIST.

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

 

[Don Y]

On 4/27/2022 1:15 AM, Phil Hobbs wrote:

Don Y wrote:

[It\'s not uncommon to have manufacturing tolerances of -60%, +300%. Easy to
accommodate if you are smart about it.]

A pity you didn\'t just replace NIST.

Lots of things don\'t need to be qualified in \"engineering units\".

How do you test that the *hammer* you are building, today, is as good
as the hammers you\'ve built in the past? Or, a screwdriver? Just
how \"durable\" should the finish on a tape rule be?

[who, besides the manufacturer, would know how to interpret those data?
What units? How to evaluate relative to other vendors\' products?]

How do you verify that the (pharmaceutical) tablet that you produced NOW
is as good as the one you produced 5 milliseconds earlier?

[Does the consumer care if a particular batch of tablets have a friability
of 1.2%? Or, variations of hardness on the order of 2KP? Or, a dissolution
time that varies by 4% in a particular sample of tablets?]

In many cases, you rely on some other (external) determinant of \"acceptable
quality\" and the goal is just to ensure repeatability of process. E.g.,
those \"good\" tablets were produced with 4.5 bogounits of force exerted during
the compression phase; make sure all of them experience a similar force. Or,
a sample of those hammers struck the test anvil 1825 times, on average, before
the handle snapped; the competitor\'s hammers broke at 1615 strikes, on average.
Etc.

Statistical Process Control becomes more important than traditional control
theory (use a conventional control loop and wrap SPC around that)

 

[Anthony William Sloman]

On Wednesday, April 27, 2022 at 7:50:56 PM UTC+10, Don Y wrote:

On 4/27/2022 1:15 AM, Phil Hobbs wrote:
Don Y wrote:

[It\'s not uncommon to have manufacturing tolerances of -60%, +300%. Easy to
accommodate if you are smart about it.]

A pity you didn\'t just replace NIST.
Lots of things don\'t need to be qualified in \"engineering units\".

How do you test that the *hammer* you are building, today, is as good
as the hammers you\'ve built in the past? Or, a screwdriver? Just
how \"durable\" should the finish on a tape rule be?

[who, besides the manufacturer, would know how to interpret those data?
What units? How to evaluate relative to other vendors\' products?]

How do you verify that the (pharmaceutical) tablet that you produced NOW
is as good as the one you produced 5 milliseconds earlier?

If it contains the same amount of the specific chemical compound that constitutes it active ingredient, it is pretty much certain to be just as good.

[Does the consumer care if a particular batch of tablets have a friability
of 1.2%? Or, variations of hardness on the order of 2KP? Or, a dissolution
time that varies by 4% in a particular sample of tablets?]

As long as the active dose gets into their body, they couldn\'t care less.

In many cases, you rely on some other (external) determinant of \"acceptable
quality\" and the goal is just to ensure repeatability of process. E.g.,
those \"good\" tablets were produced with 4.5 bogounits of force exerted during
the compression phase; make sure all of them experience a similar force.

Nobody could care less how tightly squeezed the tablets were as long as they dissolved in the right bit of the digestive system.

Or, a sample of those hammers struck the test anvil 1825 times, on average, before
the handle snapped; the competitor\'s hammers broke at 1615 strikes, on average.

The time it takes to break the handle of a hammer is worth worrying about, but it shouldn\'t ever break at all.

> Statistical Process Control becomes more important than traditional control theory (use a conventional control loop and wrap SPC around that).

No amount of statistical process control can compensate fro somebody who won\'t think about what they are measuring, and why it matters.
You just scored a massive fail on that.

--
Bill Sloman, Sydney

 

[server]

On Wed, 27 Apr 2022 04:15:50 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

Don Y wrote:
On 4/26/2022 7:59 PM, bitrex wrote:
You can often pick up used kit from local tech firms, universities
(excellent
source of kit as they often dump everything they purchased for a
GRANT project
when the grant is over), etc.  Some firms just contract disposal of
their kit
to a firm; others sell at auction (which may or may not be \"public\").
Knowing
folks at these places is a great way to get the inside track...

There is a re-seller like that near me with several dozen \"tested\"
3478As bench DMMs available for $150 per (better test the AC section
though as it uses an unobtaninum part) and another place will
calibrate it for $50.

Resellers increase the price but usually don\'t add much \"value\".  You want
to find the guy *he* buys from (usually someone at ABC Tech Corporation).

I think I\'ll pick up a couple I used them in college & they\'re still
nice meters.

I don\'t think I own equipment fast enough to calibrate a refurbed
8082 anyway, even if it\'s not the ECL that\'s the problem

Yeah, I rescued an HP 3458A many years ago.  After the initial \"pride of
rescueship\" (v \"ownership\") wore off, I realized it was just an
oversized
*4* digit DVM given that I never needed more accuracy/precision than
that!
And, surely wasn\'t going to PAY to have it calibrated to 8+ digits!

(here, bench space is far more precious than quality of kit!)

Going off BW * tr = 0.34 as the fastest edge a DSO can even assign a
sample to, much less measure the rise time of accurately, I figure a
100 MHz scope is too sluggish to calibrate a 5ns pulser on its fastest
setting. /shrug

Most of the products I\'ve designed have intentionally NOT required close
tolerances on anything.  That adds cost -- in parts or calibration labor.
So, we design products that rely on other means to make sense of their
observations (ratiometric or other \"self calibration\" tricks).

[It\'s not uncommon to have manufacturing tolerances of -60%, +300%.
Easy to
accommodate if you are smart about it.]

A pity you didn\'t just replace NIST.

Cheers

Phil Hobbs

Another NOLA story: we\'d send drawings out to machine shops and get
stuff that didn\'t fit. They responded that we should send them
drawings with tolerances, and circle some in red with the note HOLD.

Life\'s too short to worry about the small stuff, I guess.

The Silicon Bayou and similar plans never seemed to work out. That\'s
one reason why I left.





--

Anybody can count to one.

- Robert Widlar