Re: Test fixture for dielectric measurements
In the late 1980s I worked at E. I. DuPont Co at their Engineering Physics Lab in Delaware. We did a lot of dielectric measurements for the company, and also had an 8510 plus the 1970s 8409 automatic network analyzer, a two rack wide series of instruments controlled with a 9836 computer. The basis was the 8410 network analyzer.
One of the typical measurements we made was liquid dielectric measurements. We had a brass cell, with O rings, that looked like a vertical coaxial cylinder. It was filled a certain height with the liquid, and it fitted on top of the HP 4342A Q meter. We made empty and full measurements and plugged the dial setttings into a program that computers K' and K"". I think we had a heat tape around it, and could measure vs temperatur. Later I automated it with a swept measurement system and had the dielectric properties vs temperature.?
Keysight and an aftermarket Swiss? company make a surface probe that can measure flat materials and liquids. Damaskos in Pennsylvania also makes some devices.
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I've been lazy and not read the entire manual. Where do you set the coupling? I fired it up and tried all the buttons, but did not find the AC/DC coupling on my 8560A.
I presume I'd need to first measure the input and output impedances and then construct matching baluns..
Whatever is not reflected is transmitted except for any absorption due to resistive losses. So except in certain pathological cases reflection does not matter. But sometimes it does. In reflection seismology the water layer reverberation is a major aggravation.
I'm afraid I've gone off the deep end. My power feed for my bench is all shielded with Liquatite SL-516 flex conduit. I cut off the cords, and ran them from Appleton 4SS boxes (which I do *not* recommend as it gets *very* cramped). I bought them because they fit the external space nicely, but got beat up pretty badly getting the wires to fit inside. I still need to mount a 20 A EMI filter where I connect to the mains.
I've got a filter, but it's rather large and I still need to find a suitable enclosure.
This might seem like overkill, but if you investigate the radiated EMI from a GW Instek GDS-2000E series scope you'll be appalled by the radiated EMI. There is *no* shielding on the SMPS. I plan to correct that as I have a bending brake and can fabricate an enclosure, But after discovering the issue decided that shielding my power feed was worth while. Besides which I really did not have room for runnning all the power cords into power strips. The last attempt at that led to a wad of cables of absurd dimension.
As for probes, so far Bob Pease has kept me to the strait and narrow.
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Re: Hp 8903b display issue u
The part is branded with the HP part number at the top. A9U18, P/N 1820-2100 is listed as being a Fairchild 3861EPC in the service manual. The 8650 on the third line is definitely a date code.?
By 1986, when the particular device in your 8903B was manufactured, Fairchild may have been out of the F8 business. Mostek was a second source for F8 family parts, having released the 3870 in 1977.?
If you don¡¯t need the HPIB capability, I think you can remove A9 without any problems.?
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On Feb 10, 2019, at 20:46, oliver johnson via Groups.Io < nojjamaica@...> wrote: This is the A9 board that i have as you can see, this is the board when placed into the unit causes the issues with display and key inputs . <20190210_212612.jpg>
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On Sun, Feb 10, 2019 at 8:38 PM, Glen Hoag After re-reading the thread, I see that Oliver is talking about the 40 pin chip on A9. As I mentioned in my last post, depending on the serial prefix of the instrument, it is either a Fairchild 3861 PIO (parallel input/output) or a Motorola MC68B21P PIA (peripheral interface adapter), not a ROM of any kind. There is a small fusible link PROM on the board, HP P/N 08901-80004. This 32x8 ROM is used as part of the HPIB logic.
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Re: HP34702A Ohms converter issues
Maybe a dumb question have you checked that the current being to applied to the test resistor is actually what it should be? ?A whacked out current source could drive bogus readings Regards, ? Stephen Hanselman Datagate Systems, LLC 3107 North Deer Run Road #24 Carson City, Nevada, 89701 (775) 882-5117?office (775) 720-6020?mobile s.hanselman@...
a Service Disabled, Veteran Owned Small Business DISCLAIMER: This e-mail and any attachments are intended only for use by the addressee(s) named herein and may contain legally privileged and/or proprietary information. If you are not the intended recipient, any dissemination, distribution or copying of this e-mail and any attachments is strictly prohibited. If you have received this e-mail in error, please immediately notify me and permanently delete the original and all copies and printouts of this e-mail and any attachments.
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On Feb 10, 2019, at 19:06, gregdunn@... wrote: Just a follow-up: having swapped out all the active components in the Ohms section, the problem remains - 2-3x the actual resistance value on all ranges except any value over a few hundred k¦¸ reads OL.? I'm pretty sure I checked all the diodes already and found reasonable looking voltages.? So I guess it's time to start spot-checking some of the non precision resistors and seeing if any of them look iffy.
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Re: HP34702A Ohms converter issues
Just a follow-up: having swapped out all the active components in the Ohms section, the problem remains - 2-3x the actual resistance value on all ranges except any value over a few hundred k¦¸ reads OL.? I'm pretty sure I checked all the diodes already and found reasonable looking voltages.? So I guess it's time to start spot-checking some of the non precision resistors and seeing if any of them look iffy.
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Re: Hp 8903b display issue u
This is the A9 board that i have as you can see, this is the board when placed into the unit causes the issues with display and key inputs .
On Sun, Feb 10, 2019 at 8:38 PM, Glen Hoag <hoag@...> wrote: After re-reading the thread, I see that Oliver is talking about the 40 pin chip on A9. As I mentioned in my last post, depending on the serial prefix of the instrument, it is either a Fairchild 3861 PIO (parallel input/output) or a Motorola MC68B21P PIA (peripheral interface adapter), not a ROM of any kind. There is a small fusible link PROM on the board, HP P/N 08901-80004. This 32x8 ROM is used as part of the HPIB logic.
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what do you mean 8560A is not sensitive enough below 300KHz?
The frequency range is 50Hz to 2.9GHz but you MUST enable DC coupled input (by default it is always AC coupled and freq response is >100KHz)
It really meets the specs down to 50Hz. Of course you will need to choose a small RBW and it will be pretty slow but it works.
I have a 8560E which goes to 30Hz and I can measure? a 10KHz resonator with it however at 10Hz RBW it is slow. Your VNA will also be very slow
for the same reasons your SA is.
for low frequency filters such as EMI filters you really only need transmission measurement to see where the resonance is. "Reflection" is not really an issue at frequencies like 30KHz?
but still can be measured using a good directional bridge anyway.
yes, a balun can take care of the matching but I am not exactly sure if those filters are designed for a specific purely resistive load/source impedance.
In RF filters, this is always the case and the impedance is usually 50 (or 75) or rarely things like 100 or 200 or 300 ohms (resistive) so a transformer easily takes care of the matching
but i don;t know about EMI filters. For example it might have been designed to have its specified frequency response for a specific inductive or capacitive load.
In any case you will need to know that optimum impedance the filter was designed for (if that is indeed how they are designed)
However, just to see where the resonance is or to compare two filters, most of the time you dont even need to care about impedance matching. Just the SA with TG is enough
The actual insertion loss will be wrong though.
Investing on a good EMI probe and even a high frequency active probe (for in-circuit probing) to use with the SA would be my recommendation.
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On Sun, Feb 10, 2019 at 08:27 PM, Reginald Beardsley wrote:
The EMI filters are just a reason to want 30 KHz rather than 300 KHz. I've been doing a lot of probing with the SA function of the Instek MDO-2000E line. My 8560A just isn't sensitive enough below about 300 KHz which is where the majority of the noise is. Sadly I discovered that GW botched the calculation of the modulus so the series resonant notch of a crystal shows up as a peak.
So how would you evaluate the performance of an EMI filter? It surely looks like a transmission/reflection problem to me. I'm a retired reflection seismologist, so I'm very used to the time domain and impulse responses and to a large degree can look at either a time or a frequency domain plot and cartoon the other domain (thanks to Ronald Bracewell).
For that matter, how would you evaluate a crossover network? That's not 50 ohms. I would expect one would need a balun at each end, but I can't see why it matters that it's not an RF line. The conversion between balanced and unbalanced and the impedance matched would be required and the latter probably gets "interesting" if it's a 4 ohm speaker.
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Actually, I have a VNWA 3E and an xaVNA both of which are 2 port USB devices.
The VNWA has limited dynamic range above 500-600 MHz IIRC and only goes to about 1.3 GHz. The xaVNA covers 140 MHz to 2.5 GHz.
I've not actually used either one yet as I have been buying a bunch of test gear and setting up a bench. I've discovered that I don't actually have room in my current space for an 8753, but this is really just intended as a temporary bench. Eventually the bench will probably go in the library (5000+ volumes) which occupies the former 2 car garage. But I've got a dozen or more boxes of technical journals and now superfluous books to clear out.
Unfortunately, at 65 there is no work at $50/bbl oil. A friend found a bespoke programming job, but before he could get started the company got bought for pennies on the dollar and upper management were all laid off. So the job disappeared.
Playing with electronics by myself in rural Arkansas is not as much fun as working where I had people to interact with who understood what I was doing.
So now I interact with strangers in cyberspace :-(
I "retired" 11 years ago to look after my parents thinking once I got moved I'd get another contract, but before I could even begin unpacking the crash hit in 2008 and all the contract work dried up. I was having a really tough time emotionally until I discovered the EEVblog forums and the fantastic people who hang out there. But it's still feels rather weird.
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Re: Hp 8903b display issue u
After re-reading the thread, I see that Oliver is talking about the 40 pin chip on A9. As I mentioned in my last post, depending on the serial prefix of the instrument, it is either a Fairchild 3861 PIO (parallel input/output) or a Motorola MC68B21P PIA (peripheral interface adapter), not a ROM of any kind. There is a small fusible link PROM on the board, HP P/N 08901-80004. This 32x8 ROM is used as part of the HPIB logic.
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The EMI filters are just a reason to want 30 KHz rather than 300 KHz. I've been doing a lot of probing with the SA function of the Instek MDO-2000E line. My 8560A just isn't sensitive enough below about 300 KHz which is where the majority of the noise is. Sadly I discovered that GW botched the calculation of the modulus so the series resonant notch of a crystal shows up as a peak.
So how would you evaluate the performance of an EMI filter? It surely looks like a transmission/reflection problem to me. I'm a retired reflection seismologist, so I'm very used to the time domain and impulse responses and to a large degree can look at either a time or a frequency domain plot and cartoon the other domain (thanks to Ronald Bracewell).
For that matter, how would you evaluate a crossover network? That's not 50 ohms. I would expect one would need a balun at each end, but I can't see why it matters that it's not an RF line. The conversion between balanced and unbalanced and the impedance matched would be required and the latter probably gets "interesting" if it's a 4 ohm speaker.
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This may come in handy for others, I had an 8753A I got off ebay fo rmy RF bench.? It worked for one day, then went into random display and status mode, totally unusable. Most times, I got no display, but sometimes random lines and random LEDs on, no key press response. Rats...
All the power supplies looked good, no visible heat or corrosion damage, and re-seating the cards did nothing.? I got a new set of 6 eproms from Bruce Lane at Blue Feather Technology, and ta-da, the unit came back to life perfectly.? The old parts had all the labels missing, but were original, and had the 1986 code copyright. The age of those parts (checked against other part date codes) is approximately 30+ years, right on track for code failure based on the part datasheets. the threshold seems to be around 25 years for UV eproms to experience code rot.
Many older HP units have deteriorating eprom code from this same era, so it's worth exploring this as a fix, and many on-line code repositories are now up to support this. If you see completely un-explainable random operation, this is a good place to look.
all the best,
walter (walter2 -at- sphere.bc.ca)
sphere research corp.
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On 02/10/2019 07:58 PM, Dr. David
Kirkby from Kirkby Microwave Ltd wrote:
However,
if you would like to have a VNA I recommend one that has
integrated test set like 8753D (it also comes without test
set) It also has a 6GHz option?
which would be fantastic.
The external test set does offer some
advantages, which is why I bought an 8753ES option 011
(external test test). Testing high power amplifiers is one
obvious one. Almost all current high end VNAs have an
extra-cost option of a configurable test set.?
Dave.?
_._,_._,_
I haven't been following this thread, so I may be off topic, but I
wonder if you have read about a couple of VNA "modules" that run off
of a USB port on a computer? I don't know what frequency range
you need, but I think some of the modules are working up into the
low GHz region. They are far cheaper than a full-blown VNA from,
say, HP. You should, however, look for a unit that does 4-port
measurements: S11, S21, S12, S22, if available, or you'll have to
turn the UUT around to get the answers.
--doug, WA2SAY, retired RF engineer
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Re: Hp 8903b display issue u
I just opened my 8903B. A9 is the Remote Interface (HPIB) board. The CPU for the 8903B is on A8.? I also pulled up my 8903B service manual PDF downloaded from the Agilent web site several years ago. Serial prefix 2948A and above have the MC68B09P CPU; earlier models had the F8.?
The HPIB board used with the 6809 processor is fairly simple; it¡¯s just a 6821 VIA and some supporting circuitry. The board part number is 08903-60297. (Look at the bottom of the board, between the card edge connectors.?
The older board used with the F8 CPU is 08903-60118. It used the Fairchild 3861 PIO chip.?
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On Feb 10, 2019, at 18:19, Glen Hoag < hoag@...> wrote: Regarding ¡°8650¡±, are you sure you aren¡¯t looking at the date code on the chip?
I have an 8903B and an 8903E, which is the version without the signal generator. I don¡¯t remember which processors they have; I¡¯ll have to have a look inside.?
What is the part number on your A9 board? On Feb 10, 2019, at 17:31, oliver johnson via Groups.Io < nojjamaica@...> wrote: I agree with what you are saying , i see a few of th chips , but without the original programming i am stuck , thats why i wanted to know if anyone has a way to get original information so it can be put on new chips, that or i will need a doner A9 board that works this way eliminate need for chips and the need for programming,? if anyone has a spare A9 card for 8903b or have a way to program new chips with original information,? let me know. On Sun, Feb 10, 2019 at 4:52 PM, paul swedberg Oliver if it is a prom it may not really matter if you can get the part as it won't have the code. Thats the key. If you have the code you can almost always hack in a more modern device to replace it. No code = big trouble. Good luck Paul WB8TSL
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Dr. David Kirkby from Kirkby Microwave Ltd
However, if you would like to have a VNA I recommend one that has integrated test set like 8753D (it also comes without test set) It also has a 6GHz option?
which would be fantastic.
The external test set does offer some advantages, which is why I bought an 8753ES option 011 (external test test). Testing high power amplifiers is one obvious one. Almost all current high end VNAs have an extra-cost option of a configurable test set.?
Dave.?
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Re: Hp 8903b display issue update
On Sun, 10 Feb 2019 17:43:36 +0000 (UTC), you wrote: I just looked at my 8903b and the chip is an 8650 , not the 3850 or 6809 . Being that this is the only 40 pin chip on the card by default it has to be it , i did remove chip to see if it was the issue , but got the same result , any other ideas , all ideas welcome . I can't define what an 8650 is, not with a small search. I have no idea why you removed it. If it's the processor, then nothing will happen. If it's an I/O chip then something won't happen and something will fail, if there's a good check. You were talking about a ROM failure, and I'd have thought you'd have looked for an enable lead for a ROM. If you were looking for that, then you might want to look to see how ROM chips work, paying attention particularly to the OE (output enable) and CE (chip enable) lines. They aren't the same. CE turns on the whole chip, or turns it off. Some chips have only that. OE is an output enable. If that's all there is, it's functionally equivalent. You seemed to want to take a ROM off line to be able to debug something. The way to do that is to disable the chip. Tying only one line high (typically) is the way to do it. Harvey On Sun, Feb 10, 2019 at 10:24 AM, Glen Hoag<hoag@...> wrote: There are two processor variants on several HP instruments of this era. Early models were based on the Fairchild F8 (3850). HP had to redesign the CPU and HPIB boards when the F8 family went out of production. Later instruments used the 6809.
KO4BB has the ROM images for the early processor board, but not the 6809 version.
On Feb 10, 2019, at 09:02, Harvey White <madyn@...> wrote:
On Sun, 10 Feb 2019 05:29:43 +0000 (UTC), you wrote:
Thanks for the reply , was thinking of something? like you mentioned,? the only problem is i do not know what pin i have to remove.? I am also going to use the scope to probe around and see if i can make some? progress,? again all help would be great . CE or OE pin (CE is the whole chip, OE just disables outputs,
nomenclature varies).? There ought to be a decoder hung off the top
address lines in the processor, trace a wire from there back to the
prom.
Either line would do, they are most often active low.? Some chips have
both active low and active high, disabling either one would work.
Harvey
On Sat, Feb 9, 2019 at 4:41 PM, paul swedberg<paulswedb@...> wrote:? Oliver we all like to blame the most difficult and unknown thing. In this case it may be the prom is suffering from memory rot. I have a partially bad one on a 8501 display normalizer. (Just haven't gotten around to replacing it) Thank heavens the HP docs some what explain what the code is.So I would take the following approach as a suggestion. The prom should have a pin to disable it. Disable it. Plug the board in if it still hangs the system then just maybe its not the prom. Thois not to say that maybe an output or address line isn't stuck and hanging the system. Scope will give you that hint.Good luckPaulWB8TSL
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Re: Hp 8903b display issue u
Regarding ¡°8650¡±, are you sure you aren¡¯t looking at the date code on the chip?
I have an 8903B and an 8903E, which is the version without the signal generator. I don¡¯t remember which processors they have; I¡¯ll have to have a look inside.?
What is the part number on your A9 board?
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On Feb 10, 2019, at 17:31, oliver johnson via Groups.Io < nojjamaica@...> wrote: I agree with what you are saying , i see a few of th chips , but without the original programming i am stuck , thats why i wanted to know if anyone has a way to get original information so it can be put on new chips, that or i will need a doner A9 board that works this way eliminate need for chips and the need for programming,? if anyone has a spare A9 card for 8903b or have a way to program new chips with original information,? let me know. On Sun, Feb 10, 2019 at 4:52 PM, paul swedberg Oliver if it is a prom it may not really matter if you can get the part as it won't have the code. Thats the key. If you have the code you can almost always hack in a more modern device to replace it. No code = big trouble. Good luck Paul WB8TSL
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Re: Hp 8903b display issue u
I agree with what you are saying , i see a few of th chips , but without the original programming i am stuck , thats why i wanted to know if anyone has a way to get original information so it can be put on new chips, that or i will need a doner A9 board that works this way eliminate need for chips and the need for programming,? if anyone has a spare A9 card for 8903b or have a way to program new chips with original information,? let me know.
On Sun, Feb 10, 2019 at 4:52 PM, paul swedberg <paulswedb@...> wrote: Oliver if it is a prom it may not really matter if you can get the part as it won't have the code. Thats the key. If you have the code you can almost always hack in a more modern device to replace it. No code = big trouble. Good luck Paul WB8TSL
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Reginald,
If your need for a VNA is driven mostly by EMI filters and measurement, then I'd say you don't need a VNA.
A spectrum analyzer (in conjunction with some appropriate probing devices and methods) is most useful for tracking down EMI pathways, and measuring effectiveness of various cleanup techniques. You can't readily design or predict the in-service characteristics of say, a power line filter, with VNA measurements. This kind of filter is not an RF/microwave device with nice, single-ended 50 ohm I/O, and it goes in a non-RF environment.
Ed
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Re: Hp 8903b display issue u
Oliver if it is a prom it may not really matter if you can get the part as it won't have the code. Thats the key. If you have the code you can almost always hack in a more modern device to replace it. No code = big trouble. Good luck Paul WB8TSL
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Hi Peter,
Got it sorted on Windows, I usually use Linux so Python on
Windows was a bit foreign to me. My engineering PC is Windows
because I have a bunch of s/w that only runs on Windows.
Also sorted the print() statements out :)
My E4432B works well under mod except for the 617 error which is
caused with the license fail for a GSM thing which I don't care
about.
I did some sleuthing when trying to switch back didn't quite
work, it was then I found that the second part of the serial
number statement, highlighted in red below...
# Serial number
inst.write("SERV:PRODUCTION:CAL 165,0,40050868.15332;")
is actually the country code part of the serial number. i.e. GB40050868 vs US40050868
so you must ensure that if you're putting your ESG back to normal
that you copy that part of the query from...
print (inst.query("SERV:CAL? 165,0"))
I noticed that the HostID for the unit changes to, which suggests
its a calculated value based on model & serial which no doubt
serves as the basis for calculating the license numbers for the
s/w options.
regards
Tim
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