Re: VNA Resonance Methodology
Hi jmr,
Well, it's an interesting methodology for sure. I do have a Nanovna which I bought purely for evaluation purposes, but I have two proper lab-grade HP VNAs as well. Can't recall the model numbers off hand but one's good to 1.3Ghz and the other to 6Ghz (expanded from 3). Unfortunately the matching S parameter test set? for the 6Ghz one tops-out at 3Ghz, however, which is a bit of a nuisance. Still, since we are only talking 1.4Mhz (virtually DC :-)) for this test, none of that fancy stuff is necessary anyway. :-)
Jinxie
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Re: VNA Resonance Methodology
Thanks, Froggie. By all means PM me when you have access to all your test equipment again.
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Re: Sticky ink of schematics
Personally, I have found that the laser printer at home doesn't
do this while the ones at work and in the print shop I use do ---
the difference may be that the one at home is black+white only and
is of the black powder toner+fuzer variety while the others are
colour and use a waxy sort of ink.
Luckily, when I needed some schematics printed on A3 I found a
print shop that had a black+white plotter that could go up to A0
and those haven't stuck to anything (yet).
I did at one point spray some colour prints with a clear lacquer
which seemed to work but a PITA.
As Ed says, Inkjet is the best alternative.
Dave
On 27/11/2024 06:26, ed breya wrote:
toggle quoted message
Show quoted text
Like Chuck said, laser printed items tend to stick to other
stuff over time. I haven't seen it too bad from one paper sheet
to another, but definitely from paper to plastics, or (toner
sides) face to face. I've seen and heard it (sounds like peeling
Velcro apart) especially from laser printed paper pages to
(inside) vinyl covers of 3-ring binders, and plastic page
separators and such, leaving some of the print transferred.
?
I think the best way to preserve paper documents is to laser
print one-sided only, and avoid any long term contact with
plastic materials - an extra blank paper cover sheet on top can
isolate it from a plastic layer. If it must be two-sided, go
with inkjet instead.
?
Ed
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Re: HP 8341B 1992 firmware version
That is correct, the firmware is the same for both. I have used exactly this firmware to update my 8341B without issues.
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Re: HP 8594E PSU repair/debug safety checklist
Hi Group check the power switch they tend to fail on those.
if the PSU is faulty contact me on OZ11LPR@... I have alot of parts for those units.
It is a pain to work on that powersupply type.
best regards Peter
Differential probe isn't going to keep *you* safe......? The isolation
transformer might.? (And most variac's are NOT isolation transformers)
On Tue, Nov 26, 2024 at 9:53?AM Ke-Fong Lin via groups.io
<anotherlin@...> wrote:
>
> Hi everyone,
>
> My HP8594E has a temperamental PSU, sometimes everything just works fine otherwise the SA just doesn't turn on.
> Something is obviously wrong and needs to be debugged.
>
> I've not opened the case yet. I've just searched a bit the internet ().
> HP doesn't provide schematics but people have already attempted repair.
>
> I may have to work on the "mains connected" (120VAC US or 220VAC Europe) side.
> So I just want to be sure that I would be safe with a differential probe, and if I use a diff probe, an isolation transformer wouldn't be needed.
>
> Seems that "curious marc" is using a variac as some form of isolation transformer:
>
>
> In general, do you guys have some links or checklists for safety when working on these kind of switch mode power supply.
> Thanks!
>
>
> Best regards,
>
|
Re: Sticky ink of schematics
Like Chuck said, laser printed items tend to stick to other stuff over time. I haven't seen it too bad from one paper sheet to another, but definitely from paper to plastics, or (toner sides) face to face. I've seen and heard it (sounds like peeling Velcro apart) especially from laser printed paper pages to (inside) vinyl covers of 3-ring binders, and plastic page separators and such, leaving some of the print transferred.
?
I think the best way to preserve paper documents is to laser print one-sided only, and avoid any long term contact with plastic materials - an extra blank paper cover sheet on top can isolate it from a plastic layer. If it must be two-sided, go with inkjet instead.
?
Ed
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Re: HP 8341B 1992 firmware version
There is no differences in CPU board and firmware between 8340B and 8341B.
Calibration constants 79 and 98 must 2 for 8340B and 5 for 8341B, according to service manual.
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Re: VNA Resonance Methodology
Jinxie, I should return to the lab in a few weeks.
Can crank up my HP 4195A network -Spectrum analyzer (500 MHz)
Also the Boonton / Measurements GDO and Q meter
With a photo and specs of the coils you test, we can take a few tests.
Enjoy
Jon
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Re: VNA Resonance Methodology
OK..... quite a lot to digest there and it's rather late at night in my zone right now so I'll have to re-read this in the stark light of morning. I think it would be illustrative to post a photo of my current test set-up and reference plane. I suspect it might draw some healthy criticism from those of a particular disposition here, but no matter. I'm big enough to take a few insults. :)
If I forget overnight, feel free to remind me....
?
Jinx.
?
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Re: Sticky ink of schematics
Modern laser printers and copiers use a finely powdered plastic toner to create the letters and pictures that are on the page. The plastic dust is placed onto the paper electrostatically, and is fused to the paper with very hot silicone rubber pinch roller. When you put such a printed sheet of paper into a vinyl binder, the same plasticizer that makes the vinyl soft and flexible will out gas and soften the plastic toner that is the printing on the paper. In my experience, you are screwed at this point. The plastic letters will be sticking to the adjacent sheet with the same vigor as they stick to the original sheet. -Chuck Harris On Mon, 25 Nov 2024 20:01:10 -0800 "Lexter Negron via groups.io" <lexternegron@...> wrote: Will do. An update, I found exactly what to call this courtesy of
someone from EEVblog. Was found thru searching "toner" in the old
threads.
/g/HP-Agilent-Keysight-equipment/topic/a_new_threat_to_the_hp_manual/24809333
/g/HP-Agilent-Keysight-equipment/topic/24809337
/g/HP-Agilent-Keysight-equipment/topic/24809401
I've currently stopped any separation on my part to see what options
I can take. Also I'm in the Houston area in Texas. Some of the stuff
was stored in a neighboring state. For the most part it gets hot and
humid but can get snow/frost. I suspect heating from many summers in
a warehouse did this.
-Lex
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Re: HP 8594E PSU repair/debug safety checklist
Don't get too enamored with tracing out and debugging your power supply, 9 times out of 10, the problem will be simply a case of bad electrolytic capacitors. I am not being casual with my statistics, this is hard won personal experience. The quickest way to "get'er'done", is to get an ESR meter, and check each electrolytic capacitor. Look exclusively for those that have ESR much greater than 1 ohm. When you find one, remove it, and measure its capacitance. Most of the time, it be low in an inverse relation to how high the ESR is. When you find a bad cap, replace ALL identical caps in the supply. Temperamental supplies are that way often because the electrolytic capacitors get worse when they are cold. For instance, a becoming very bad 100uf cap may be 25uf when hot, but only 2uf when cold. 25uf isn't great, but it may be enough to keep running, but 2uf isn't enough to start the supply (and warm up the cap). I do virtually all of my power supply debugging and repair with the power off, and no schematics. -Chuck Harris On Tue, 26 Nov 2024 06:53:47 -0800 "Ke-Fong Lin via groups.io" <anotherlin@...> wrote: Hi everyone,
My HP8594E has a temperamental PSU, sometimes everything just works
fine otherwise the SA just doesn't turn on. Something is obviously
wrong and needs to be debugged.
I've not opened the case yet. I've just searched a bit the internet (
). (
) ) HP
doesn't provide schematics but people have already attempted repair.
I may have to work on the "mains connected" (120VAC US or 220VAC
Europe) side. So I just want to be sure that I would be safe with a
differential probe, and if I use a diff probe, an isolation
transformer wouldn't be needed.
Seems that "curious marc" is using a variac as some form of isolation
transformer:
In general, do you guys have some links or checklists for safety when
working on these kind of switch mode power supply. Thanks!
Best regards,
|
Re: VNA Resonance Methodology
Note that the 6cm diameter loop antenna ideally needs to form a closed loop, so one end of the loop connects to the centre pin of the coaxial connector and the other end of the loop connects to the outer (ground) of the coaxial connector.
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Re: VNA Resonance Methodology
If it helps, I dug out one of my test solenoids and put a 390pF ATC 800B cap across it and used the loop antenna method to find the resonance with the VNA set to s11. See the image below where the resonance was at 1.945 MHz. If you use a modern synthesised VNA like this (even a nanovna), the proximity of the test resonator will not pull the frequency of the VNA. This is unlike a typical old school GDO where the GDO will lose its frequency calibration if you bring anything too close to the GDO's external coil as it will cause the GDO to change frequency.?
?
In the example case below I could bring the loop antenna really close to the solenoid and the dip frequency did not change. Because the resonator capacitor is huge at 390pF it dominates any stray capacitance from the loop antenna. It's even possible to touch the solenoid and the loop antenna together and the dip stubbornly stays at the same frequency. But you can see that this isn't necessary as I got a decent dip with the setup in the image below.
?
If I had fitted a variable capacitor it would be possible to watch the resonant frequency change in real time as the capacitance was changed. You can't do that with a GDO :)
There is no calibration performed on the VNA, it is running uncalibrated as it is only necessary to look for a dip with this method. You do have to set the VNA to 1dB/div or less. If using something like a nanovna I'd recommend using 0.2dB/div.
?
You can see the loop antenna is just a loop of tinned copper wire with about a 6cm diameter. This is big enough to pass over the test coil with a good clearance. This method won't work so well for physically smaller solenoids and a different type of pickup loop may be required. It may even require a different test method. However, you are making a large air cored solenoid so this method should work really well :)
?
?
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Re: Troubleshooting a 8591e with opt 130
Marco, ? For A1-A5 and G1 to G3: +0.019V/ 1=+4.8V For G4 to G6:? -7.4V / +14.28V With my 8595E, A5 -16dB is activated with CORR=ON, and OFF when CORR=OFF. This would mean that I would probably have a similar problem if my A5 attenuator was not working, I would have a signal at -5dBm instead of -20dBm. ? I don't have the behavior you have, going from -9dBm to -10dBm. ? Yves
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Pulling CT2 Demodulator (opt 110) from HP8594E
I have a 8595E that I want to remove the CT2 Demodulator (option 110) card from.
Now I am wondering if any rewiring is required? I tried to find the option 110 installation
instructions, but sofar no luck.
?
Any ideas?
?
Wilko
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Re: Troubleshooting a 8591e with opt 130
Yves,?
?
I finally had some time to solder and to the measurements, sorry for the hold up.
Below are the results
?
Next I checked all the lines to see if they would ever change by changing the ref level and log/lin setting. It looks like we are onto something there.
| ? |
low |
high |
| A1 |
0,003 |
5,15 |
| A2 |
0,003 |
5,15 |
| A3 |
0,003 |
5,15 |
| A4 |
0,003 |
5,15 |
| A5 |
0,003 |
0,004 |
| G1 |
0,004 |
5,15 |
| G2 |
0,004 |
5,15 |
| G3 |
0,004 |
5,15 |
| ? |
low |
high |
| G4 |
14,238 |
-5,5 |
| G5 |
14,238 |
-5,755 |
| G6 |
14,238 |
-3,075 |
?
A5 seems broken, G6 looks somewhat suspicious. The level being about 15dB off also fits the A5 16dB attenuator not working. I'll take out the A7 Analog board to directly solder a wire to U111 pins 8 and 9 to see if the output of the 74HC374 has failed or that the IOB12 is faulty.?
Perhaps the function of IOB12 is identifiable because IOB12 also switches several other signals like A7 U201 Pins 2 and 3 (10dB Section in or out), A7 U11 pin 19 (ATP1), d4 of A7 U104 (Bw control Dac), A7 U107 pin 9 (IFG5). Since IFG5 seems to work I suspect IOB12 must be working.?
?
Then some other strange behavior caught my eye. Ofcourse we can expect some additional noise since both the LogAmp and the Amp control have quite some gain, they mis the top of the enclosure and they have several antennas running off the board to measure the levels, but a big difference was observed in noisefloor between two ref levels.?
Note the 2 plots below. The only difference is Ref level -9 and -10. The -9dB ref has upward spikes jumping around, the -10dB has downward spikes but a ~15dB higher noisefloor.
I guess this might have to do with the 16dB attenuator not kicking in.
?
Are G4/G5/G6 at the same levels on your analyzer??
?
Marco
?
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Re: Sticky ink of schematics
Greetings,
?
I asked a longtime friend who spent his career in the printing and photo lithography industry.
?
He suggested reaching out to the ¡°American Academy of Forensic Sciences¡± located in Colorado Springs, CO.
?
FWIW I hope this helps.
?
Regards,
?
Ken
?
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Show quoted text
On Mon, Nov 25, 2024 at 08:01 PM, Lexter Negron wrote:
found thru searching "toner"
I read in your links to the threads...that ISO...which I paraphrase here... they think "if there is transfer, and sticking, it is likely toner."
AFAIK, that... if I have articulated their claim correctly... is untrue.
There are several kinds/types of 'imaging materials.'
"ink' and "toner" are two of them; but, 'ink' is? not the same as 'toner'
Oil based inks, used on offset printing... can and do... stick pages together... and transfer, as well.
I'm not sure it ultimately matters; but, you can sometimes determine what printing technology was used by examining the print, and the paper.
Sometimes... particularly in older monographs... and some manuals... you can find information about how the documented was printed, in the document's colophon.
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Re: HP 8341B 1992 firmware version
Hi saevar,
I saw them but these are labeled as for 8340B not 8341B. Do you know whether firmware for 8340B and 8341B is exactly the same?
Regards
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Re: VNA Resonance Methodology
On Tue, Nov 26, 2024 at 04:30 PM, Jinxie wrote:
On Mon, Nov 25, 2024 at 10:12 PM, jmr wrote:
"The other alternative would be to use a ferrite core based inductor. It should be possible to get a Q of about 400 at 1.45 MHz with a small ferrite core inductor with about 50uH inductance. But this won't be suitable for large signal operation."
Due to core saturation?
?
Yes, and also the ferrite can introduce non-linear artefacts at levels below saturation. This type of distortion can happen if you use the ferrite in a narrow bandpass filter for example.
?
Note that you can mimic a GDO with a VNA if you set it to s11 and set the scale to 1dB/div or less. Then connect a simple small loop of wire across the far end of your test coax. A wire loop about about 6cm diameter should be fine when looking for resonant tanks below 30MHz or so.? You don't have to calibrate anything on the VNA. Just hold the test loop near the inductor under test assuming it has been resonated with a parallel capacitor. It's best to experiment with the orientation of the test loop with respect to the inductor under test.
?
At the resonant frequency of the tank you should be able to see a tiny downwards blip in the s11 trace. It might only be at about -0.2dB to start with but you can move the loop closer if you don't see a blip initially.
?
For your application, this approach will outperform any GDO assuming you have a VNA with a good display and a reasonably fast sweep rate. Unlike a GDO, there's nothing to adjust, you just hold the loop near the inductor and look for the frequency where the resonant tank absorbs energy from the VNA. Then use the marker to tell you the resonant frequency if you need a bit more accuracy.
?
?
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Re: Sticky ink of schematics
On Mon, Nov 25, 2024 at 08:01 PM, Lexter Negron wrote:
found thru searching "toner"
I read in your links to the threads...that ISO...which I paraphrase here... they think "if there is transfer, and sticking, it is likely toner."
AFAIK, that... if I have articulated their claim correctly... is untrue.
?
There are several kinds/types of 'imaging materials.'
"ink' and "toner" are two of them; but, 'ink' is? not the same as 'toner'
?
Oil based inks, used on offset printing... can and do... stick pages together... and transfer, as well.
?
I'm not sure it ultimately matters; but, you can sometimes determine what printing technology was used by examining the print, and the paper.
?
Sometimes... particularly in older monographs... and some manuals... you can find information about how the documented was printed, in the document's colophon.
?
?
|
Jinxie
Froggie the Gremlin