Re: 8640B won't switch to highest +20 dBm range
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I had a problem on mine many years ago and found a bad reed relay, though my
problem had to do with switching between the high and low halves of the frequency
bands. There is a board with a bunch of reed relays rather deep inside, and I
wonder if they also used some of them for switching attenuator ranges. Might
be worth checking the schematic and see if there are any on the attenuator pages.
?
John K0GCJ
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Re: 8640B won't switch to highest +20 dBm range
Hi: You can test the attenuator within the instrument. you can connect a SMA cable to attenuator input, check the level at N output connector .
Test the attenuation correct or not. + 20dBm had a switch control to the final AMP circuit, check the service manual.
Regard Tony Cheung JUL 16 2024 ?
On Tuesday, July 16, 2024 at 07:28:59 AM GMT+8, Dave W6OQ via groups.io <david.hostetler@...> wrote:
I just purchased a pretty clean 8640B signal generator, but it has a couple of little problems. I already fixed a loose set screw down inside on the option 001 variable audio oscillator and will be adjusting and calibrating the audio oscillator tomorrow.
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It also has an 003 option and 2232A serial prefix.
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But I am having a problem with the RF output step attenuator where it won't switch to the highest +20 dBm range, but will switch 1 step below the lowest -130 dBm setting, though that causes the output meter level to drop to zero.?
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The upper ranges check as perfectly calibrated to a fairly new digital oscilloscope and within a dB or so to a TinySA ULTRA spectrum analyzer. It appears that someone has had the attenuator housing open as evidenced buy an original HP paper sticker that has been sliced along a seam.
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It seems an odd situation, but does anyone have an idea what is going on? Unless I get a better clue, I plan to pull the attenuator out and open it up tomorrow.?
?
Thanks
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Re: 8640B won't switch to highest +20 dBm range
Here is a weird idea: Has the power amp been bypassed or partly failed? I have worked on a few of these and never saw this. When you say wont switch: is the attenuator knob not set right, not sure I understand.? J. Kruth
In a message dated 7/15/2024 7:28:59 PM Eastern Standard Time, david.hostetler@... writes:
?
I just purchased a pretty clean 8640B signal generator, but it has a couple of little problems. I already fixed a loose set screw down inside on the option 001 variable audio oscillator and will be adjusting and calibrating the audio oscillator tomorrow.
?
It also has an 003 option and 2232A serial prefix.
?
But I am having a problem with the RF output step attenuator where it won't switch to the highest +20 dBm range, but will switch 1 step below the lowest -130 dBm setting, though that causes the output meter level to drop to zero.?
?
The upper ranges check as perfectly calibrated to a fairly new digital oscilloscope and within a dB or so to a TinySA ULTRA spectrum analyzer. It appears that someone has had the attenuator housing open as evidenced buy an original HP paper sticker that has been sliced along a seam.
?
It seems an odd situation, but does anyone have an idea what is going on? Unless I get a better clue, I plan to pull the attenuator out and open it up tomorrow.?
?
Thanks
|
8640B won't switch to highest +20 dBm range
I just purchased a pretty clean 8640B signal generator, but it has a couple of little problems. I already fixed a loose set screw down inside on the option 001 variable audio oscillator and will be adjusting and calibrating the audio oscillator tomorrow.
?
It also has an 003 option and 2232A serial prefix.
?
But I am having a problem with the RF output step attenuator where it won't switch to the highest +20 dBm range, but will switch 1 step below the lowest -130 dBm setting, though that causes the output meter level to drop to zero.?
?
The upper ranges check as perfectly calibrated to a fairly new digital oscilloscope and within a dB or so to a TinySA ULTRA spectrum analyzer. It appears that someone has had the attenuator housing open as evidenced buy an original HP paper sticker that has been sliced along a seam.
?
It seems an odd situation, but does anyone have an idea what is going on? Unless I get a better clue, I plan to pull the attenuator out and open it up tomorrow.?
?
Thanks
|
Re: HP 3852a extended memory modules info
A second thing is to consider whether you are replacing CMOS with TTL compatible CMOS.? That T (TTL compatible) makes a difference in the part name.
Harvey
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On 7/15/2024 3:28 PM, Wilko Bulte wrote: Be careful while exchanging different TTL families. Not always it works, not always is a faster logic family working when replacing an older TTL family. This can lead to new problems which are very hard to debug.
Don't ask me how I know...
Wilko
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Re: VNA calibration kit to 50 GHz
Yes, why indeed the extra λ/8 and 3λ/8 waveguide sections, from a waveguide cal kit user? Like you, i have shorts and the loads, and just need the λ/4 spacer for a TRL cal, but why these other two sections?
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Agreed, 6 Layer Cards instead of 4 Layer Cards. Grin. ? 
? My wife is actually very understanding. We both have our hobbies. There are no disagreements about supplies for either hobby. ? The way we see it, hobbies keep us happy. They also keep our minds continuously busy and happy people like to stay with each other longer – 46+ Years and going strong. ? Ross ?
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From: [email protected] < [email protected]> On Behalf Of Tom via Metronet Sent: Monday, July 15, 2024 12:43 PM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP free e-book ? Yep. Do it your way, over-engineer as much as you want, and the more useless, the better. If the wife won’t approve your expense account, tell her at least you aren’t chasing skirts in bars. ? ? ? Well said. ? I too have found renewed joy in Retirement. I have the time to design anything I want, to my specifications, I can layout the PCBs the way I want to my satisfaction, build and test, and just have fun… ??ALL on MY SCHEDULE. ? Yup, totally useless time spent. ? Highly recommended. ? Ross ? ? Thanks to you for your attention! This activity gives me an unreasonable joy. Yes, I spent my life in electronics, but in the last 15 years I was more a manager than a technician, and however the worries of a company on your shoulders much “dilute” the pleasure. Now that I am retired, restoring and documenting this forgot equipment, I found again the enthusiasm of when I was fifteen, amplified by the fact that what I do is absolutely useless… ?(this is a fundamental component of pleasure…)
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Right!!!
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-----Original Message----- From: [email protected] < [email protected]> On Behalf Of Dave McGuire Sent: Monday, July 15, 2024 12:36 PM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP free e-book "Useless". It's called "living" and doing what you want to with your life, and personally I can't think of anything more useful to a person than that. That's what life IS. By all means, go forth and hack on tech, and love every minute of it. -Dave On July 15, 2024 2:27:03 PM "si_emi_01 via groups.io" <wellington@...> wrote: Well said.
I too have found renewed joy in Retirement. I have the time to design anything I want, to my specifications, I can layout the PCBs the way I want to my satisfaction, build and test, and just have fun… ALL on MY SCHEDULE.
Yup, totally useless time spent.
Highly recommended.
Ross
From: [email protected] <[email protected]> On Behalf Of Gianni Becattini via groups.io
Sent: Sunday, July 14, 2024 10:56 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP free e-book
Thanks to you for your attention!
This activity gives me an unreasonable joy. Yes, I spent my life in electronics, but in the last 15 years I was more a manager than a technician, and however the worries of a company on your shoulders much “dilute” the pleasure.
Now that I am retired, restoring and documenting this forgot equipment, I found again the enthusiasm of when I was fifteen, amplified by the fact that what I do is absolutely useless… (this is a fundamental component of pleasure…)
?????
Thanks!
-- Dave McGuire, AK4HZ New Kensington, PA
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Re: HP 83590A - Help understanding frequency band switching
Tony, have you read the theory of operation for the 83590A? In particular the frequency tuning section? The band nos. correspond to the harmonic multiplication that occurs in the YTM. Band 1,? ?2.0-7.7GHz? no multiplication, 2.0-? ? ? ? ? ? ? ? ? 7.7GHz output. The YTM is not used ,? ? ? ? ? ? ? ? YIG only. Band 2,? ?3.5-6.75GHz YIG tuning,? ? ? ? ? ? ? ?x2 multiplication, YTM output 13.5GHz. Band 3,? ?4.5-6.67GHz. YIG tuning,? ? ? ? ? ? ? ?x3 multiplication, YTM output? ? ? ? ? ? ? ?12.5-20GHz.
Band 0 would be for 10MHz to 2.4GHz output on several plugins. It is a down converted band. Band 4 would be for 18.6-26.5GHz output on a few plugins. As you surmised. There is band overlap so that when you have a wider sweep near a band edge the sweeper can pick the upper or lower tuning band, so that it only has to sweep one band, not across 2 bands. It can sweep across all three (or 4 bands, or more if needed). There is a slight pause in the sweep to allow for band edge crossing delays and settling time, when you sweep across band edges. Don Bitters?
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Re: HP 3852a extended memory modules info
Be careful while exchanging different TTL families. Not always it works, not always is a faster logic family working when replacing an older TTL family. This can lead to new problems which are very hard to debug.
Don't ask me how I know...
Wilko
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Yep. Do it your way, over-engineer as much as you want, and the more useless, the better. If the wife won’t approve your expense account, tell her at least you aren’t chasing skirts in bars. ? ?
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From: [email protected] < [email protected]> On Behalf Of si_emi_01 via groups.io Sent: Monday, July 15, 2024 2:27 PM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP free e-book ? Well said. ? I too have found renewed joy in Retirement. I have the time to design anything I want, to my specifications, I can layout the PCBs the way I want to my satisfaction, build and test, and just have fun… ??ALL on MY SCHEDULE. ? Yup, totally useless time spent. ? Highly recommended. ? Ross ? ? Thanks to you for your attention! This activity gives me an unreasonable joy. Yes, I spent my life in electronics, but in the last 15 years I was more a manager than a technician, and however the worries of a company on your shoulders much “dilute” the pleasure. Now that I am retired, restoring and documenting this forgot equipment, I found again the enthusiasm of when I was fifteen, amplified by the fact that what I do is absolutely useless… ?(this is a fundamental component of pleasure…)
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"Useless". It's called "living" and doing what you want to with your life, and personally I can't think of anything more useful to a person than that. That's what life IS. By all means, go forth and hack on tech, and love every minute of it. -Dave On July 15, 2024 2:27:03 PM "si_emi_01 via groups.io" <wellington@...> wrote: Well said.
I too have found renewed joy in Retirement. I have the time to design anything I want, to my specifications, I can layout the PCBs the way I want to my satisfaction, build and test, and just have fun… ALL on MY SCHEDULE.
Yup, totally useless time spent.
Highly recommended.
Ross
From: [email protected] <[email protected]> On Behalf Of Gianni Becattini via groups.io
Sent: Sunday, July 14, 2024 10:56 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP free e-book
Thanks to you for your attention!
This activity gives me an unreasonable joy. Yes, I spent my life in electronics, but in the last 15 years I was more a manager than a technician, and however the worries of a company on your shoulders much “dilute” the pleasure.
Now that I am retired, restoring and documenting this forgot equipment, I found again the enthusiasm of when I was fifteen, amplified by the fact that what I do is absolutely useless… (this is a fundamental component of pleasure…)
?????
Thanks!
-- Dave McGuire, AK4HZ New Kensington, PA
|
Well said. ? I too have found renewed joy in Retirement. I have the time to design anything I want, to my specifications, I can layout the PCBs the way I want to my satisfaction, build and test, and just have fun… ??ALL on MY SCHEDULE. ? Yup, totally useless time spent. ? Highly recommended. ? Ross ?
toggle quoted message
Show quoted text
From: [email protected] < [email protected]> On Behalf Of Gianni Becattini via groups.io Sent: Sunday, July 14, 2024 10:56 PM To: [email protected]Subject: Re: [HP-Agilent-Keysight-equipment] HP free e-book ? Thanks to you for your attention! This activity gives me an unreasonable joy. Yes, I spent my life in electronics, but in the last 15 years I was more a manager than a technician, and however the worries of a company on your shoulders much “dilute” the pleasure. Now that I am retired, restoring and documenting this forgot equipment, I found again the enthusiasm of when I was fifteen, amplified by the fact that what I do is absolutely useless… ?(this is a fundamental component of pleasure…)
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Re: VNA calibration kit to 50 GHz
Well, you got me, I don't know from experience but can guess that, in order to cover the full waveguide band, you need some varying lengths. Also there may be specific calibration routines that used the specified length to develop correction factors. I would like to hear why from an actual waveguide cal kit user. When I was doing waveguide on the ANA (8510C) I did not have a cal kit so used my own waveguide shorts and loads, not the best way. Got good results, however!? Jeff
In a message dated 7/15/2024 12:09:20 PM Eastern Standard Time, salmon.na@... writes:
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thanks, that's good. But with TRL in waveguide you only need a thru (direction connection of waveguide ends), a reflect, and λ/4 line, then why do you need the λ/8 and 3λ/8 waveguide sections? I'm guessing this might be for a LRL calibration ie λ/8 line, reflect, 3λ/8 line. If that is the case, then why would you need a LRL calibration, if you already have a TRL calibration. There must be a good reason for having all three (λ/8, ?λ/4, 3λ/8 waveguide sections) as you see these being sold together, i'm just wonding how you make best use of these/
many thanks, Neil
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Re: VNA calibration kit to 50 GHz
thanks, that's good. But with TRL in waveguide you only need a thru (direction connection of waveguide ends), a reflect, and λ/4 line, then why do you need the λ/8 and 3λ/8 waveguide sections? I'm guessing this might be for a LRL calibration ie λ/8 line, reflect, 3λ/8 line. If that is the case, then why would you need a LRL calibration, if you already have a TRL calibration. There must be a good reason for having all three (λ/8, ?λ/4, 3λ/8 waveguide sections) as you see these being sold together, i'm just wonding how you make best use of these/
many thanks, Neil
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On 7/15/24 00:56, Gianni Becattini via groups.io wrote: Thanks to you for your attention!
This activity gives me an unreasonable joy. Yes, I spent my life in electronics, but in the last 15 years I was more a manager than a technician, and however the worries of a company on your shoulders much “dilute” the pleasure.
Now that I am retired, restoring and documenting this forgot equipment, I found again the enthusiasm of when I was fifteen, amplified by the fact that what I do is absolutely useless… ?(this is a fundamental component of pleasure…) I hope this does not diminish your pleasure, but documenting and preserving history is never useless. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: VNA calibration kit to 50 GHz
I believe that the 1/8 & 3/8 sections are only for waveguide, the SOLT is coax. Really hard to make a meaningful open in waveguide as it radiates and has a return loss of about 10 dB, not 0 dB, also improper reflection phase, not 0 degrees (or close) like a shielded open. J. Kruth
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I can see for the TRL calibration if the T is a direction connection between the connectors ends, line L is a λ/4 section wavelength, and for the SOLT you need a short, an open and a load, so why the interest λ/8 and 3λ/8 sections for calibration? Are there other calibration routines which use these? Just wondering, as if i buy some of these bit, as might as well get those which will enable a good calibration, even on a budget.
many thanks, Neil
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Re: VNA calibration kit to 50 GHz
I can see for the TRL calibration if the T is a direction connection between the connectors ends, line L is a λ/4 section wavelength, and for the SOLT you need a short, an open and a load, so why the interest λ/8 and 3λ/8 sections for calibration? Are there other calibration routines which use these? Just wondering, as if i buy some of these bit, as might as well get those which will enable a good calibration, even on a budget.
many thanks, Neil
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Re: HP 3852a extended memory modules info
74LS245 is the basic model but uses more current with up to 90mA per unit and 12ns propagation delay - we have 5 so up to 450mA
74HCT245 CMOS version 70mA max and 15ns propagation delay - 300mA for 5 unit. delta 150mA
74AHCT245 FAST CMOS 75mA max and 8.7ns propagation delay -? 375mA delta 75mA from LS?
74ACT245 FAST CMOS 50mAmax and 8ns propagation? delay. - 250mA so 200mA less than LS?
All have same pinout. ACT is best from a current usage versus speed. Any of these will work but HCT is slower than LS in theory . In practice it might not matter at all and will be the same.
Maciej
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Yiu On Tony C
Dave McGuire