I'm considering purchase of an HP3457A for use in metrology, primarily for setting DC voltage with 7.5 digits of precision.
It's not a metrology unit.? ?
It seems that I can purchase an HP3457A for a few hundred dollars, calibrated. I've reviewed the datasheet, and the operating manual, I can't see how it extracts the last extended digit in what appears to be a 6.5 digit meter in all stated specifications.
?
I realize that the counting speed is very low at that high resolution, and there may be better quality or faster choices. I'm on a budget for this one, I have bought discounted Solartron meters in the past and am quite happy with that value as well.
?
Bottom of the test equipment market here, could a HP3457A be made to display 7.5 digits in DC volts as-is?
? I believe one can only get the last digit via the GPIB bus.? As far as I am aware, it is basically noise, and not actually worth having. I think you need to accept it's a very decent 6.5 digit meter. I have one, which I bought used about 30 years ago. I sent it to Keysight for cal about 5 years ago, and it was still in spec.?
I have seen Kiethley 2001's at quite reasonable prices. If you want 7.5 digits, that's probably a better bet.
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I'm considering purchase of an HP3457A for use in metrology, primarily for setting DC voltage with 7.5 digits of precision. It seems that I can purchase an HP3457A for a few hundred dollars, calibrated. I've reviewed the datasheet, and the operating manual, I can't see how it extracts the last extended digit in what appears to be a 6.5 digit meter in all stated specifications.
?
I realize that the counting speed is very low at that high resolution, and there may be better quality or faster choices. I'm on a budget for this one, I have bought discounted Solartron meters in the past and am quite happy with that value as well.
?
Bottom of the test equipment market here, could a HP3457A be made to display 7.5 digits in DC volts as-is?
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Re: HP8753 E and ES Inverted display fix & how to revitalize keypads
Liked, subscribed!
--
With best regards
Tam HANNA
Enjoy electronics? Join 21k4 other followers by visiting the Crazy Electronics Lab at
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HP8753 E and ES Inverted display fix & how to revitalize keypads
I decided to make some repair videos about how to fix the most common issues with HP8753 series network analyzers.
?
Here is my first attempt where I cover how to fix the inverted display issue & non-functional keys.? I may do more of these covering other topics (stepped attenuator issues, troubleshooting, etc).? Welcoming feedback.
?
?
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On 15. Dec 2024, at 16:01, Adrian Godwin via < artgodwin@...> wrote: HPs cooling engineers must all have shared the same hobby: deafening rock music.
Only the first one. After that the group was doomed by it's own products.
:-)
These days I'm playing with a Rohde&Schwarz FSA (FASC actually) I picked up in a trash bin.? Its 2 Units, 65kg together, 350W power consumption, linear power supply.
I feared the worst when I switched it on, but to my surprise the fans are close to inaudible. You can listen to your radio without ramping up the volume.
R&S probably had similar specs concerning operating temperatures. But perhaps hired airflow engineers whose hobby was bird watching?
cheers Martin
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Re: Source for HP System 2 case cover retaining screws
If you guys are interested in researching companies which once made these screws, try this:
?
0570-1171
Torx, Rochester, IN?? P/N 920-46590-570
Lewis Screw, Chicago
?
0515-1245
Camcar Screw, Rockford, IL
?
0510-0043
Waldes-Kohinoor, Long Island, NY ? P/N 5133-14-S-ZD-R
Industrial Retaining Ring Inc., Irvington, NJ?? P/N 1000-14-ST-ZD
Anderton Darby, Clifton, NJ?? P/N 1500-14-ZD
?
0510-0952
Waldes-Kohinoor, Long Island City, NY?? P/N X5133-9-S-ZD
Industrial Retaining Ring Inc., Irvington, NJ?? P/N? 1000X-9-ST-ZD
?
Vladan
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Has anyone a manual for a Maury Microwave 8450P SC calibration kit?
Has anyone got a data sheet or manual for the above mentioned VNA calibration kit??
-- Dr David Kirkby Ph.D Kirkby Microwave Ltd Email: drkirkby@... Web: Telephone 07910 441670 (UK) or +44 7910 441670 (international) Registered in England and Wales, company number 08914892.? Registered office: Stokes Hall Lodge, Burnham Rd, Althorne, Essex, CM3 6DT
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Re: Perpetual licence fees - what's the best option?
On Tue, 17 Dec 2024 at 01:16, David Kirkby < drkirkby@...> wrote: Minitab only do Windows licenses now. Some users of Macs pay for a student license to complete the statistics module.?
I should rephrase that. The Open University (OU) provides Minitab for students doing some of the statistics courses. Minitab is only available on Windoze, but there is also a web version, although the OU does not provide licenses for the web version. Some students with Macs pay for the web version - I think the student price is $50 or so. Unfortunately I believe there are some parts of the M140 statistics module that can't be completed with the web version, but they are probably fairly small, and so students using the web version of Minitab should be able to pass the module.
Anyway, I would not want to use a web version of a program.
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Re: Perpetual licence fees - what's the best option?
In far off days I used to do the Unix ports for Minitab (back when there was a
Unix market).? Those were simple days, an executable + some supporting files :-)
I always liked Minitab, it was a pretty simple stat program.? Maybe it's
changed, I haven't been involved with it for 20 years.
Minitab only do Windows licenses now. Some users of Macs pay for a student license to complete the statistics module.?
Jamovi looks interesting, but there are lots of moving parts under the hood
(embedded web server + web browser in a virual environment ...).? If it installs
and works, great.? I've been bitten a couple times by changes in supporting libraries
that break code and that can be fun to track down.? For whatever reason, python
seems to be more prone to that.
Jamovi can run on a webserver, but one can just download a Windoze or Linux executable. It comes packaged with its own copy of R, but it can use another version of R if there's one on the system.
In the not so gui oriented model, there's Istat which has been around since 79 for
basic analysis.? Gnu PSPP is an alternative to SPSS.
? Paul
? I was not aware of GNU PSPP.? That might be an interesting alternative for the Open University and other universities to consider in place of Minitab. However, Jamovi seems to have a strong following in the academic community, probably because it uses R as the core. R is the choice for most professional statisticians. However basic R has no GUI interface at all, and the most popular interface, Rstudio, is not user friendly either. You need to know R to use it. In contrast, although Jamovi uses R, users don't need to know R to use it.? I personally quite like R, despite not being particularly keen on statistics. But R is not good for an introductory statistics course.
Dave
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Re: Source for HP System 2 case cover retaining screws
Yup, I know what you mean - normally the screw pulls the cover on or off nice and smoothly. But, if the metalwork is banged up or deformed enough (very common), it galls up the aluminum and can be very tight, so you have to be careful to not damage the drive tangs in the screw head or the starting threads from excessive torque. It can also snap the little retainer clip apart on removal. Most non-lost damaged screws I've found were from lids that were way too tight.
?
Ed
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Hi Ed, ? I don't think there is a capacitor, and that it is DC coupling for the whole band. The warning on the front panel of the 8751A is "Damage Level, 20dBm, ±2VDC MAX” (±3VDC in operating manual). In the HP catalog it gives 0dBm as a limit for 5Hz-500MHz, but this is very general information. In the operating manual, the detailed specifications are given for receivers: 50 Ohms, and finally the max input level is -6dBm for the range from 5Hz to 4kHz...so, it is normal to have the input overload error message, if I try to put 0dBm at 5Hz. So, my 8751A meets these specifications. ? Yves ? 
? ? Maybe in 10 Hz cutoff, it's capacitor-coupled, but in 5 Hz mode, it's actually DC-coupled to save another cap. If so, then DC drift due to some fault might be pushing it out of bounds, also accounting for the delayed error response. Is this a 1 meg or 50 ohm input? What kind of caps are at the input? If it's high-Z like 1 meg, then it's more like a standard scope input, which could need something up to around a 1 uF to solidly reach 5 or 10 Hz cutoff. Plastic caps would typically be used here. If it's 50 ohms, then for AC-coupling the C would have to be huge, and certainly electrolytic, so subject to DC leakage current issues that could upset the input amplifier.
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Re: Source for HP System 2 case cover retaining screws
On Tue, Dec 17, 2024 at 02:58 AM, ed breya wrote:
Just use regular screws of the right length and thread
Sure, I do. Except I stick with countersunk heads - looks nicer.
But the problem is, often the covers are quite tightly fitting into the slots, and can't just be slid out by hand once the securing screw is removed. Then you end up trying to lever them off with a small flat blade screwdriver in any gap available. Which there usually aren't...
?
It's much nicer to have the panel pulled out just by turning that screw.
?
Also 'historical accuracy' - when you sank a lot of money and time into acquiring, cleaning and repairing old gear, it's nice to get all the little details right.
?
Matt Huszagh:
The HP 0570-1171 is a pozi 6-32 0.46-in screw. This part number is given (probably among other places) in the HP 8566B RF section volume 1 manual (2410A series Dec '84) in the general parts listing on page 11.
The HP 0515-1245 is a Torx T15 M3.5x0.6 12mm screw (description: "Screw-Specialty 90-DEG-FLT-HD Torx-T15 M3.5X0.6 12mm-LG SST-300 Passivated"). I've found this mentioned in at least two places: an HP 16700B and a new HP 8566B manual (I can provide manual details if you want, just ask). Unfortunately, there is some inconsistency in manual descriptions. The 16700B manual lists this as a M3.5 screw whereas the 8566B manual lists it as a 6-32 screw. But, Keysight currently lists it as a M3.5, so that's what I've been taking as the truth.
?
Thanks for those part numbers.? Actually both imperial and metric are 'true'? - HP originally used imperial threads, then gradually chaged to metric. At different times in different countries. Some devices even contain a mix of metric and imperial fasteners.? Most of my old HP gear is Imperial, but a few latter ones are metric. You get good at recognizing the difference.
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Re: HP 8566B issue above 18.5GHz ?
Hi Don,
After performing presel peak at 19GHz it looks like the amplitude response starts to look quite OK. Maybe the previous owner of the analyzer performed the calibration incorrectly and that's why I observed a sudden drop in amplitude? I tried to find what is the sequence to restore the analyzer's factory settings (factory reset) but I can't find the right command. Do you maybe remember how to do a factory reset?
?
?
Best regards,
Wojciech
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Maybe in 10 Hz cutoff, it's capacitor-coupled, but in 5 Hz mode, it's actually DC-coupled to save another cap. If so, then DC drift due to some fault might be pushing it out of bounds, also accounting for the delayed error response. Is this a 1 meg or 50 ohm input? What kind of caps are at the input? If it's high-Z like 1 meg, then it's more like a standard scope input, which could need something up to around a 1 uF to solidly reach 5 or 10 Hz cutoff. Plastic caps would typically be used here. If it's 50 ohms, then for AC-coupling the C would have to be huge, and certainly electrolytic, so subject to DC leakage current issues that could upset the input amplifier.
?
Ed
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Re: HP8594E repair with "ADC-2V FAILL"
Hi Vincent,
?
my short was on the same board as yours, only a different tantalum cap.
As I do not have an IR camera, I identified the faulty cap by using my 6.5 digit Ohmmeter (HP34401).
The shorted one was the one where shunt resistance was lowest, was quite easy to see with milliOhm resolution.
Now, I'm waiting for replacement caps...
Thanks again for your great guidance!
?
Tom
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Re: Perpetual licence fees - what's the best option?
On Sunday 15 December 2024 04:56:14 pm Dave McGuire via groups.io wrote: ?"You will own nothing and be happy". Rude gesture in their general direction... ? ?Explanations of this, why it is bad, why it is unnecessary, and why
people should avoid it are met with blank stares. ?The same kind of
blank stares that result from people being told about "free" online
services, the fact being that if you receive value for free, you are the
product. ?People just don't get it.
? ?People are generally clueless. ?I've all but given up trying to save
them from their own stupidity. ?You can only yell "you are heading
toward a cliff!" for so long before it becomes tiresome. Yup... -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space, ?a critter that can be killed but can't be tamed. ?--Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin
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Re: Source for HP System 2 case cover retaining screws
Just use regular screws of the right length and thread - some are English and some are metric. Don't even bother with flatheads - standard panheads are more durable, and there's really no need for that back edge to have countersunk screws. They won't be captive anymore, but so what? If you lose them, just put in fresh ones. You'll never have to struggle with this issue again, so no more screw anxiety.
?
Ed
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Re: 3577A multiple problems - update
Oh, one more clue:
If I disconnect the 30 MHz input to the fast processor board the
error messages disappear and the PLL remains solidly locked.
Peter
On 12/16/2024 8:57 AM, Dave_G0WBX via
groups.io wrote:
toggle quoted message
Show quoted text
Re:-
I wonder if I could pull them, read them out and reprogram onto
new chips.? If one is on the edge that might fix it.? EPROMs do
go bad...
Good, if you can be sure you read the EPROM as originally
programmed, not while it is in it's faulty state.
As others have said, it could also be a bad bus
transceiver/buffer, either not pulling it's output all the way
up or down, or "leaking" significantly when it's output is
supposed to be in it's high z state, or it's input thresholds
have changed.
A memory address decoder problem can cause mayhem too, for
example two chips intermittently being selected at the same time
will cause trouble.? One of the more difficult faults to trace.
I'd get a decent 'scope, trigger it from a bus access qualifier
related with instruction fetching, and look for bus contention,
or "weak" signals.? (Analogue 'scopes are often better at that
sort of work.? DSO's often lie like a cheap watch, unless you
take "Greate Care" to ensure you have one with sufficient
sampling rate, and trace memory to catch the fastest signal on
the board in full fidelity, often the CPU clock, but not
always.? Even then some miss glitches.
If the general logic is all on sockets, just "refreshing" the
IC seating can often help, but doing that one chip at a time
takes too long, so general the whole board is done and tried
again.
At worst, the "fault" might then be permanent, and may be
easier to track down.
I learnt that, when I used to fault find to component level on
the old Data General Nova 3 and 4 series minicomputers "Back in
the day", as well as the third party peripherals they used.?
Disc controllers and a semi autonomous Mass Spectrometer I/O
board.? Often with some 200 TTL IC's on them!? (15 inch square
multi-layer boards!)
One particularly troublesome mixed signal board I recall, over
many days of odd bits of spare time, to prove a point, I removed
each analogue and digital IC and it's socket in turn, and
refitted that IC directly soldered to the board in the same
position whence it had come from.
The exception was any IC that had a direct connection
off-board.? They got expensive turned pin sockets. ? ALL the
problems then vanished and never came back!? The result was so
profound (the board in question had been officially scrapped as
BER. ) The company started making those boards in that style,
even using the same style turned pin sockets!? Product
reliability with the end customers went up enormously, and our
in house service workload reduced to sensible proportions.
Regards.
Dave 'KBV
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Re: Source for HP System 2 case cover retaining screws
When working on a missile in the navy, we
used modeling clay to contain the swath from a drilling operation.
Glenn
On 12/16/2024 3:47 AM, W6KX via
groups.io wrote:
Hear, hear! I would participate in a
group buy.
In addition, has anyone a recommendation
on re-threading the receiving end of these screws? I have done
HELICOILs but containing debris from drilling and such makes
it a dicey operation.
I have an 8664A in which I now hope to never
find the cut off end of the HELICOIL.
Mike
--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI, FRA, NRA-LM ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"
|
Re: 3577A multiple problems - update
I had similar experiences "back in the day" with PDP-11 based voice banking systems.? Thousands and thousands of TTL chips many with sockets then huge wire-wrapped backplanes.? A nightmare of millions of connections any one of which could turn intermittent at any time.? Countless frustrating hours with the old huge Gould logic analyzers.? The big improvements in reliability of more modern systems came about due to the elimination of so many connection points being replaced by much higher integration in chips.
Not sure if you saw my later post about how removing the fast processor board eliminates the unlock and CPU error messages. There's a lot of interaction and the fast processor has tentacles throughout the instrument.? As a goof I pulled the fast processor address latches (a couple of 74S374 chips) and tried running the thing, but it really didn't like that and hung up pretty early on so it doesn't tell me much.? I put a couple of machined pin sockets in those locations in case I might need to pull those chips again.? I'm not sure this troubleshooting route will be fruitful.
I don't have extenders so probing is very unwieldy.? I have a good setup of scopes and logic analyzers but such troubleshooting can be VERY time consuming.? I have a line on securing a replacement unit and will go that route.? After I do the experiments I needed this for in the first place, I will try board swapping to at least know which board it is, then maybe spot a replacement somewhere.
There is also the possibility things are going wrong because of the bad trace memory chips so I will see if anything is different once the replacements arrive and are installed.
Peter
toggle quoted message
Show quoted text
On 12/16/2024 8:57 AM, Dave_G0WBX via groups.io wrote:
Re:-
I wonder if I could pull them, read them out and reprogram onto new chips.? If one is on the edge that might fix it.? EPROMs do go bad...
Good, if you can be sure you read the EPROM as originally programmed, not while it is in it's faulty state.
As others have said, it could also be a bad bus transceiver/buffer, either not pulling it's output all the way up or down, or "leaking" significantly when it's output is supposed to be in it's high z state, or it's input thresholds have changed.
A memory address decoder problem can cause mayhem too, for example two chips intermittently being selected at the same time will cause trouble.? One of the more difficult faults to trace.
I'd get a decent 'scope, trigger it from a bus access qualifier related with instruction fetching, and look for bus contention, or "weak" signals.? (Analogue 'scopes are often better at that sort of work.? DSO's often lie like a cheap watch, unless you take "Greate Care" to ensure you have one with sufficient sampling rate, and trace memory to catch the fastest signal on the board in full fidelity, often the CPU clock, but not always.? Even then some miss glitches.
If the general logic is all on sockets, just "refreshing" the IC seating can often help, but doing that one chip at a time takes too long, so general the whole board is done and tried again.
At worst, the "fault" might then be permanent, and may be easier to track down.
I learnt that, when I used to fault find to component level on the old Data General Nova 3 and 4 series minicomputers "Back in the day", as well as the third party peripherals they used. Disc controllers and a semi autonomous Mass Spectrometer I/O board.? Often with some 200 TTL IC's on them!? (15 inch square multi-layer boards!)
One particularly troublesome mixed signal board I recall, over many days of odd bits of spare time, to prove a point, I removed each analogue and digital IC and it's socket in turn, and refitted that IC directly soldered to the board in the same position whence it had come from.
The exception was any IC that had a direct connection off-board.? They got expensive turned pin sockets. ? ALL the problems then vanished and never came back!? The result was so profound (the board in question had been officially scrapped as BER. ) The company started making those boards in that style, even using the same style turned pin sockets!? Product reliability with the end customers went up enormously, and our in house service workload reduced to sensible proportions.
Regards.
Dave 'KBV
|
Dr. David Kirkby, Kirkby Microwave Ltd
Martin
Guy Dunphy