Re: Scan From 1404A Amplifier Manual
Jeremy,
No problem.? I'm just glad to hear from you.? I was getting worried...?
Unfortunately, while trying to track down where the noise starts and probing around on the A9 board, I must've shorted the -12.6V rail and, apparently the safeguards didn't guard it.? I found the problems and have it running again (as you might've seen) but now I'm back to it.
Thanks for checking that.? I figured it wasn't something that would be there in a properly-functioning model and that confirms it.
Thanks again, Barry - N4BUQ
From: "Jeremy Nichols" <jn6wfo@...>
To: "HP-Agilent-Keysight-equipment" <[email protected]>
Sent: Monday, April 22, 2024 9:57:38 PM
Subject: Re: [HP-Agilent-Keysight-equipment] Scan From 1404A Amplifier Manual
Barry,
Finally getting back to you on the Chop circuit. Using my 140B¡¯s internal calibrator as a source for both channels of the 1402A, I don¡¯t see any difference in beam width or intensity between Chop and Alt.?
Sorry I can¡¯t?be more helpful.? Jeremy Nichols
707-529-2639
Jeremy, The reason I'm looking into those waveforms is that when I switch the amplifier to CHOP mode, the traces become a bit "fat".? It appears there's some sort of high-frequency noise that's causing the traces to appear fatter in the negative direction - i.e. the trace is there but there's a wider "shadow" on the negative side of the trace.? I was thinking it was probably the chop multi-vibrator getting into the power rails and that still might be it; however, I'm also wondering if the blanking between the chopping action might not be working properly which could cause that ghosting effect. If I recall, the scope you obtained recently is configured just like mine with a 1421A time-base and a 1404A vertical amplifier.? If so, if you select at least two channels and select CHOP mode, do your traces change - especially do they become fatter?? I'm thinking they probably do not and there's something wrong with my scope/plugin but I'm curious to find out whether you see that same behavior and, if so, it could be an anomaly of these scopes (doubtful). Thanks, Barry - N4BUQ I have that manual. Let me check.
Would anyone have the manual for the 1404A 4-channel amplifier plugin?? I would like to see what the waveforms in Fig. 8-25 (Ring Counter Measurement Conditions and Waveforms) look like.? The online versions are pretty poor images and I can't really tell if what I'm seeing - particularly for #4 - are what they should be and a decent picture would really help.
Thanks,
Barry - N4BUQ
|
Re: Scan From 1404A Amplifier Manual
Barry,
Finally getting back to you on the Chop circuit. Using my 140B¡¯s internal calibrator as a source for both channels of the 1402A, I don¡¯t see any difference in beam width or intensity between Chop and Alt.?
Sorry I can¡¯t?be more helpful.? Jeremy Nichols
707-529-2639
Jeremy,
The reason I'm looking into those waveforms is that when I switch the amplifier to CHOP mode, the traces become a bit "fat".? It appears there's some sort of high-frequency noise that's causing the traces to appear fatter in the negative direction - i.e. the trace is there but there's a wider "shadow" on the negative side of the trace.? I was thinking it was probably the chop multi-vibrator getting into the power rails and that still might be it; however, I'm also wondering if the blanking between the chopping action might not be working properly which could cause that ghosting effect.
If I recall, the scope you obtained recently is configured just like mine with a 1421A time-base and a 1404A vertical amplifier.? If so, if you select at least two channels and select CHOP mode, do your traces change - especially do they become fatter?? I'm thinking they probably do not and there's something wrong with my scope/plugin but I'm curious to find out whether you see that same behavior and, if so, it could be an anomaly of these scopes (doubtful).
Thanks, Barry - N4BUQ I have that manual. Let me check.
Would anyone have the manual for the 1404A 4-channel amplifier plugin?? I would like to see what the waveforms in Fig. 8-25 (Ring Counter Measurement Conditions and Waveforms) look like.? The online versions are pretty poor images and I can't really tell if what I'm seeing - particularly for #4 - are what they should be and a decent picture would really help.
Thanks,
Barry - N4BUQ
|
Re: HP 140B LVPS -12.6V Not Working
Even though the 2N3704 and 2N3391 transistors are apparently ECB, the 1854-0071, at least the one that was at Q484, is CBE (l-r looking at it from the flat side).
I checked it a bit further and it turned out that Q484's CE was a nice resistor and no base connection at all.? I don't know how I read 0.7V drops across BC and BE earlier but that must have been some kind of mistake on my part.
I tacked in a 2n3904 (because that's what I have that's closest to it) and things are working again!? That said, is there reason not to use the 2n3904 here?? I see where Ic on a 2n3704 is higher (500mA) than the 2n3904 (200mA) but that shouldn't be any concern here.? I'm not finding proper information on a 1854-0071 that has leads like the one I took out so I'm not sure what else might be of concern using a 2N3904 here.
Thanks for all the patience with me with this!
Thanks, Barry - N4BUQ
According to the HEWLETT PACKARD TRANSISTORS & DIODES.? COMMERCIAL CROSS-REFERENCE, an 1854-0071 crosses to a 2N3704 or a 2N3391.? Both of those are ECB (apologies to David if those were ones you'd already mentioned).? No wonder things haven't made sense to me.? At least the dots seem to coincide with the emitter as I was thinking.? Now I have more checking to do... Thanks, Barry - N4BUQ
From: "n4buq" <n4buq@...>
To: "HP-Agilent-Keysight-equipment" <[email protected]>
Sent: Monday, April 22, 2024 6:43:15 PM
Subject: Re: [HP-Agilent-Keysight-equipment] HP 140B LVPS -12.6V Not Working
I've been cross-checking the board against the schematic.? I thought I had the dot convention correct (emitter) but then the differences between a few of the transistors on the board made me realize something didn't match so I need to be even more careful if I end up needing to replace those. I'm just glad wires don't have dots. Thanks,
Barry - N4BUQ I would've guessed that the dot marks the collector. At least that
was the convention used on all the parts I encountered as a kid. The
literature of the day often referred to "the collector dot". But of
course that doesn't mean that other companies/countries followed
that convention, so I'm curious: Are you just guessing (say, based
on a quick DMM diode check, in which case you're rolling the dice),
or did you cross-check with some circuit-tracing against a
schematic?
And if you're talking about a TO-92, there is no standard pinout.
Parts of US design generally follow EBC, UK parts often follow CBE
(making it easy to swap with US parts by simply installing the other
way around), Japanese parts are frequently BEC (I've also
encountered ECB), but "generally" does mean "not always" here. You
have to check, don't assume.
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070
On 4/22/2024 3:38 PM, n4buq wrote:
Something about this is confusing
me.? Looking at the board, the transistors and diodes all have
a dot at one lead.? I was thinking that dot indicated the
emitter and for some transistors, that holds.? It agrees with
the 2n3409 I replaced and most of the metal-hat transistors.?
With the flat of the 2n3904's TO92 facing me, left to right is
EBC.? For Q484, though, the diode across BE (I can't read it
very well but I think that's CR485 or CR486) is connected to
the center lead and the right-hand lead (facing the
transistor's flat).? Do those not follow the same convention
as, say, a 2n3904?? I'm used to either EBC being left-to-right
facing the flat or, possibly, B on the left or right, but this
is puzzling to me.
|
Re: N9020A - Right to Repair
One of the key tenets of "right to repair" is that those proprietary alignment / calibration tools must be made available at a reasonable cost... The catch is there's usually no stipulation about "reasonable cost", so they can make it available for $1M and call it a day.
But the good thing is if it's "available" it will end up "out there" eventually
On Mon, Apr 22, 2024 at 6:17?PM Peter Gottlieb via <hpnpilot= [email protected]> wrote: Right to Repair can easily be gotten around by the manufacturers.
I have a R&S transceiver which came from a surplus lot.? It had a problem with
one module and I swapped in another module from a different unit.? While it
worked, the alignment was off and power output across the frequency range is not
within spec.
This can easily be fixed by the use of their proprietary service software, but
that software is not available outside of the company.? Heck, I can't even
adjust the main oscillator to be right on frequency without that software.? Will
they do it for me? Probably not; others have tried and unless you're a
government or large commercial entity they won't talk to you.? And if you
finally got them to?? The price I head quoted was several times what the radio
cost me.? Even with governments they only operate on a contract basis.
Plenty of things are like that, this is but one example. Technically you have
"repaired" your device, but it will never operate to spec ever again.
Peter
On 4/22/2024 7:56 PM, Ed Marciniak via wrote:
> It isn¡¯t too much to ask for that you be able to replace commodity components
> that fail with identical replacements. It¡¯s also not unreasonable to want to
> replace a board with a functional equivalent with the understanding that the
> original manufacturer might choose not to provide tech support (free, paid by
> subscription, or pay per issue).
>
> In the computer industry, the Moss Magnuson Act (US) doesn¡¯t allow a
> manufacturer to void a warranty for using compatible aftermarket parts, like
> commodity DRAM modules or fiber optic modules. They¡¯re not required to support
> or troubleshoot compatibility issues. You could end up having to replace the
> commodity components if you end up at an impasse obtaining support under a
> contract (and then swapping back after problem resolution). A common example
> would be a cisco router with Cisco charging stupid amounts of money for DRAM
> modules or fiber transeivers.
>
> The embedded PC motherboards are specialized enough that it would potentially
> be difficult but not impossible to find a replacement. I don¡¯t know that it¡¯s
> come up yet, but I¡¯m other countries like the UK, where a manufacturer can¡¯t
> tie a license to a piece of hardware¡in principle someone might be able to
> turn the screws and successfully litigate their way into forcing a
> manufacturer to make a license portable, or by extension license a replacement
> board.
>
> If only I had a UK mailing address and corporate entity¡
>
|
Re: N9020A - Right to Repair
Right to Repair can easily be gotten around by the manufacturers.
I have a R&S transceiver which came from a surplus lot.? It had a problem with one module and I swapped in another module from a different unit.? While it worked, the alignment was off and power output across the frequency range is not within spec.
This can easily be fixed by the use of their proprietary service software, but that software is not available outside of the company.? Heck, I can't even adjust the main oscillator to be right on frequency without that software.? Will they do it for me? Probably not; others have tried and unless you're a government or large commercial entity they won't talk to you.? And if you finally got them to?? The price I head quoted was several times what the radio cost me.? Even with governments they only operate on a contract basis.
Plenty of things are like that, this is but one example. Technically you have "repaired" your device, but it will never operate to spec ever again.
Peter
toggle quoted message
Show quoted text
On 4/22/2024 7:56 PM, Ed Marciniak via groups.io wrote: It isn¡¯t too much to ask for that you be able to replace commodity components that fail with identical replacements. It¡¯s also not unreasonable to want to replace a board with a functional equivalent with the understanding that the original manufacturer might choose not to provide tech support (free, paid by subscription, or pay per issue).
In the computer industry, the Moss Magnuson Act (US) doesn¡¯t allow a manufacturer to void a warranty for using compatible aftermarket parts, like commodity DRAM modules or fiber optic modules. They¡¯re not required to support or troubleshoot compatibility issues. You could end up having to replace the commodity components if you end up at an impasse obtaining support under a contract (and then swapping back after problem resolution). A common example would be a cisco router with Cisco charging stupid amounts of money for DRAM modules or fiber transeivers.
The embedded PC motherboards are specialized enough that it would potentially be difficult but not impossible to find a replacement. I don¡¯t know that it¡¯s come up yet, but I¡¯m other countries like the UK, where a manufacturer can¡¯t tie a license to a piece of hardware¡in principle someone might be able to turn the screws and successfully litigate their way into forcing a manufacturer to make a license portable, or by extension license a replacement board.
If only I had a UK mailing address and corporate entity¡
|
Yeah, the PXAs we have at work take a long time to come up, and they always seem to be doing realignments right when you want to make a measurement!? Another irritating thing is that if I don't power up the PXA on the bench, our test software takes several long minutes to figure out that the PXA is not on the GPIB.? For whatever reason, that's not the case for the PNA-X; the S/W figures it out almost immediately.? Not that the PNA-X (and especially the e-cal box) don't take half an eternity to boot up or warm up....
Jim
------ Original Message ------
Date 4/22/2024 7:26:03 PM
Subject Re: [HP-Agilent-Keysight-equipment] N9020A
The phase noise of the E4406A is quite good but there's a lot of high performance options for measuring phase noise these days...? it's hard to keep up with it all. For many years I've wanted an Agilent E5052A SSA as used at my place of work. However, I may end up buying one of the modern alternatives for a fraction of the price!?
If you watch an E4406A or a PSA when they are booting, you can see it testing the IF preselector filters. It will say something like aligning LC Prefilter Wide, LC Prefilter Narrow, XTAL Prefilter Wide, XTAL Prefilter Narrow. I've not used a 12 bit E4406A but I assume it will still have these preselector filters.
The MXA will have them as well and it will probably flash up on screen messages when aligning or testing them.?
|
The phase noise of the E4406A is quite good but there's a lot of high performance options for measuring phase noise these days...? it's hard to keep up with it all. For many years I've wanted an Agilent E5052A SSA as used at my place of work. However, I may end up buying one of the modern alternatives for a fraction of the price!?
If you watch an E4406A or a PSA when they are booting, you can see it testing the IF preselector filters. It will say something like aligning LC Prefilter Wide, LC Prefilter Narrow, XTAL Prefilter Wide, XTAL Prefilter Narrow. I've not used a 12 bit E4406A but I assume it will still have these preselector filters.
The MXA will have them as well and it will probably flash up on screen messages when aligning or testing them.?
|
Re: Seeking HP 80000 Data Generator (aka 2900A) system software
HI Brian,
I found this zip file in my stash. To generate the diskettes you'll need a PC that can run LIFUTIL.exe. I hope this is what you need!
Regards,
Stan
|
Re: HP 140B LVPS -12.6V Not Working
According to the HEWLETT PACKARD TRANSISTORS & DIODES.? COMMERCIAL CROSS-REFERENCE, an 1854-0071 crosses to a 2N3704 or a 2N3391.? Both of those are ECB (apologies to David if those were ones you'd already mentioned).? No wonder things haven't made sense to me.? At least the dots seem to coincide with the emitter as I was thinking.? Now I have more checking to do...
Thanks, Barry - N4BUQ
From: "n4buq" <n4buq@...>
To: "HP-Agilent-Keysight-equipment" <[email protected]>
Sent: Monday, April 22, 2024 6:43:15 PM
Subject: Re: [HP-Agilent-Keysight-equipment] HP 140B LVPS -12.6V Not Working
I've been cross-checking the board against the schematic.? I thought I had the dot convention correct (emitter) but then the differences between a few of the transistors on the board made me realize something didn't match so I need to be even more careful if I end up needing to replace those. I'm just glad wires don't have dots. Thanks,
Barry - N4BUQ I would've guessed that the dot marks the collector. At least that
was the convention used on all the parts I encountered as a kid. The
literature of the day often referred to "the collector dot". But of
course that doesn't mean that other companies/countries followed
that convention, so I'm curious: Are you just guessing (say, based
on a quick DMM diode check, in which case you're rolling the dice),
or did you cross-check with some circuit-tracing against a
schematic?
And if you're talking about a TO-92, there is no standard pinout.
Parts of US design generally follow EBC, UK parts often follow CBE
(making it easy to swap with US parts by simply installing the other
way around), Japanese parts are frequently BEC (I've also
encountered ECB), but "generally" does mean "not always" here. You
have to check, don't assume.
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070
On 4/22/2024 3:38 PM, n4buq wrote:
Something about this is confusing
me.? Looking at the board, the transistors and diodes all have
a dot at one lead.? I was thinking that dot indicated the
emitter and for some transistors, that holds.? It agrees with
the 2n3409 I replaced and most of the metal-hat transistors.?
With the flat of the 2n3904's TO92 facing me, left to right is
EBC.? For Q484, though, the diode across BE (I can't read it
very well but I think that's CR485 or CR486) is connected to
the center lead and the right-hand lead (facing the
transistor's flat).? Do those not follow the same convention
as, say, a 2n3904?? I'm used to either EBC being left-to-right
facing the flat or, possibly, B on the left or right, but this
is puzzling to me.
|
Re: Agilent E4404B Spectrum Analyzer With Dead PSU Repair
No worries. We can still be friends! LOL!
Jim
toggle quoted message
Show quoted text
------ Original Message ------ From "Dave McGuire" <mcguire@...> To [email protected]Date 4/22/2024 7:05:37 PM Subject Re: [HP-Agilent-Keysight-equipment] Agilent E4404B Spectrum Analyzer With Dead PSU Repair
I'm sorry Jim, I didn't mean to sound disagreeable. I typed and sent that too fast.
Rifa problems are caused by moisture absorption, not line voltage or lightning. This is a very well-known and understood thing everywhere. We deal with it all the time at the museum.
-Dave
On 4/22/24 19:59, Dave McGuire wrote:
Pittsburgh, not much lightning here.
Nearly every Rifa capacitor I see is swollen and crazed, and when you see that, detonation isn't far behind.
-Dave
On 4/22/24 17:55, Jim Ford wrote:
I suspect you live in lightning country, Dave. Southern California where I live is just about the least likely place on the planet for lightning strikes. After damaging at least 2 instruments in the process of replacing (old) RIFAs, I'm not risking that again. YMMV.
Jim
------ Original Message ------
From "Dave McGuire" <mcguire@...>
To [email protected]
Date 4/22/2024 4:12:11 PM
Subject Re: [HP-Agilent-Keysight-equipment] Agilent E4404B Spectrum Analyzer With Dead PSU Repair
On 4/22/24 14:07, Jim Ford wrote:
But I don't replace old RIFAs on sight anymore. Too much collateral damage by a ham-fisted engineer with a soldering iron in his hand, and explosions are rare here in 120 VAC land. Those in 240 VAC land risk explosions, though. Uh, I've had three go so far just this year. The risk is surely higher in 240V-land, but I strongly advise replacing them on sight here too.
-Dave
-- Dave McGuire, AK4HZ
New Kensington, PA
-- Dave McGuire, AK4HZ
New Kensington, PA
|
Re: Agilent E4404B Spectrum Analyzer With Dead PSU Repair
I'm sorry Jim, I didn't mean to sound disagreeable. I typed and sent that too fast.
Rifa problems are caused by moisture absorption, not line voltage or lightning. This is a very well-known and understood thing everywhere. We deal with it all the time at the museum.
-Dave
toggle quoted message
Show quoted text
On 4/22/24 19:59, Dave McGuire wrote: ? Pittsburgh, not much lightning here.
? Nearly every Rifa capacitor I see is swollen and crazed, and when you see that, detonation isn't far behind.
?????????? -Dave
On 4/22/24 17:55, Jim Ford wrote:
I suspect you live in lightning country, Dave.? Southern California where I live is just about the least likely place on the planet for lightning strikes.? After damaging at least 2 instruments in the process of replacing (old) RIFAs, I'm not risking that again.? YMMV.
Jim
------ Original Message ------
?From "Dave McGuire" <mcguire@...>
To [email protected]
Date 4/22/2024 4:12:11 PM
Subject Re: [HP-Agilent-Keysight-equipment] Agilent E4404B Spectrum Analyzer With Dead PSU Repair
On 4/22/24 14:07, Jim Ford wrote:
But I don't replace old RIFAs on sight anymore.? Too much collateral damage by a ham-fisted engineer with a soldering iron in his hand, and explosions are rare here in 120 VAC land.? Those in 240 VAC land risk explosions, though. ? Uh, I've had three go so far just this year.? The risk is surely higher in 240V-land, but I strongly advise replacing them on sight here too.
?????????? -Dave
-- Dave McGuire, AK4HZ
New Kensington, PA
--
Dave McGuire, AK4HZ
New Kensington, PA
|
Yes, I will keep it on the wishlist!? Thanks for sharing the plots.? I've heard with it's relatively low phase noise it can be used to measure PN as well.
Jim
------ Original Message ------
Date 4/22/2024 7:01:23 PM
Subject Re: [HP-Agilent-Keysight-equipment] N9020A
When used within its limits, the 14 bit E4406A is a really nice analyser. I typically use mine to measure the accuracy of various attenuators and it can also be used to test the accuracy of the 1dB steps of a lab sig gen. See below for an automated test of an old Aeroflex 3414 sig gen when stepped down to -120dBm in 1dB steps. The 1 dB steps are quite accurate on this sig gen (according to the E4406A at least). I do this with a switched external LNA ahead of the E4406A and this lets me measure down to -120dBm in two chunks as below. The LNA has very low VSWR which helps minimise uncertainty. Other sig gens typically aren't quite this impressive, but most of my sig gens are within about +/- 0.25dB when tested like this.
|
When used within its limits, the 14 bit E4406A is a really nice analyser. I typically use mine to measure the accuracy of various attenuators and it can also be used to test the accuracy of the 1dB steps of a lab sig gen. See below for an automated test of an old Aeroflex 3414 sig gen when stepped down to -120dBm in 1dB steps. The 1 dB steps are quite accurate on this sig gen (according to the E4406A at least). I do this with a switched external LNA ahead of the E4406A and this lets me measure down to -120dBm in two chunks as below. The LNA has very low VSWR which helps minimise uncertainty. Other sig gens typically aren't quite this impressive, but most of my sig gens are within about +/- 0.25dB when tested like this. 
|
Re: Agilent E4404B Spectrum Analyzer With Dead PSU Repair
Pittsburgh, not much lightning here.
Nearly every Rifa capacitor I see is swollen and crazed, and when you see that, detonation isn't far behind.
-Dave
toggle quoted message
Show quoted text
On 4/22/24 17:55, Jim Ford wrote: I suspect you live in lightning country, Dave.? Southern California where I live is just about the least likely place on the planet for lightning strikes.? After damaging at least 2 instruments in the process of replacing (old) RIFAs, I'm not risking that again.? YMMV.
Jim
------ Original Message ------
From "Dave McGuire" <mcguire@...>
To [email protected]
Date 4/22/2024 4:12:11 PM
Subject Re: [HP-Agilent-Keysight-equipment] Agilent E4404B Spectrum Analyzer With Dead PSU Repair
On 4/22/24 14:07, Jim Ford wrote:
But I don't replace old RIFAs on sight anymore.? Too much collateral damage by a ham-fisted engineer with a soldering iron in his hand, and explosions are rare here in 120 VAC land.? Those in 240 VAC land risk explosions, though. ? Uh, I've had three go so far just this year.? The risk is surely higher in 240V-land, but I strongly advise replacing them on sight here too.
?????????? -Dave
-- Dave McGuire, AK4HZ
New Kensington, PA
--
Dave McGuire, AK4HZ
New Kensington, PA
|
It isn¡¯t too much to ask for that you be able to replace commodity components that fail with identical replacements. It¡¯s also not unreasonable to want to replace a board with a functional equivalent with the understanding that the original manufacturer might choose not to provide tech support (free, paid by subscription, or pay per issue).
In the computer industry, the Moss Magnuson Act (US) doesn¡¯t allow a manufacturer to void a warranty for using compatible aftermarket parts, like commodity DRAM modules or fiber optic modules. They¡¯re not required to support or troubleshoot compatibility issues. You could end up having to replace the commodity components if you end up at an impasse obtaining support under a contract (and then swapping back after problem resolution). A common example would be a cisco router with Cisco charging stupid amounts of money for DRAM modules or fiber transeivers.
The embedded PC motherboards are specialized enough that it would potentially be difficult but not impossible to find a replacement. I don¡¯t know that it¡¯s come up yet, but I¡¯m other countries like the UK, where a manufacturer can¡¯t tie a license to a piece of hardware¡in principle someone might be able to turn the screws and successfully litigate their way into forcing a manufacturer to make a license portable, or by extension license a replacement board.
If only I had a UK mailing address and corporate entity¡
|
Re: Agilent E4404B Spectrum Analyzer With Dead PSU Repair
I suspect you live in lightning country, Dave. Southern California where I live is just about the least likely place on the planet for lightning strikes. After damaging at least 2 instruments in the process of replacing (old) RIFAs, I'm not risking that again. YMMV.
Jim
toggle quoted message
Show quoted text
------ Original Message ------ From "Dave McGuire" <mcguire@...> To [email protected]Date 4/22/2024 4:12:11 PM Subject Re: [HP-Agilent-Keysight-equipment] Agilent E4404B Spectrum Analyzer With Dead PSU Repair On 4/22/24 14:07, Jim Ford wrote:
But I don't replace old RIFAs on sight anymore. Too much collateral damage by a ham-fisted engineer with a soldering iron in his hand, and explosions are rare here in 120 VAC land. Those in 240 VAC land risk explosions, though. Uh, I've had three go so far just this year. The risk is surely higher in 240V-land, but I strongly advise replacing them on sight here too.
-Dave
-- Dave McGuire, AK4HZ
New Kensington, PA
|
Ah, the E4406A is the one with the hole around 321.4 MHz, isn't it?? That could be really annoying if you were working with say, 225-450 MHz, as I was a few years back.? I do have it on my wishlist, nonetheless, as they were going for only a few hundred dollars when the wireless carriers started dumping them.
Jim Ford Laguna Hills, California, USA
"And we know that God causes all things to work together for the good of those who love God and are called according to his purpose for them." Romans 8:28 (NLT)
------ Original Message ------
Date 4/22/2024 6:43:00 PM
Subject Re: [HP-Agilent-Keysight-equipment] N9020A
If it helps promote how good these MXA analysers are, there is a nice hardware feature in the IF section of the PSA and the PXA and MXA analysers that helps when making critical dynamic range measurements.
There should be a suite of IF preselector filters that limit the bandwidth that the digital IF is exposed to. On the PSA, this means there is a lumped or crystal filter that gets selected to provide this preselection automatically based on span/RBW settings. I don't know how many IF preselector filters there are in the PSA but there are also a few preselector filters like this in the PXA and MXA. The IF bandwidth can be adjusted from a few kHz up to about 1.8MHz or so by selecting a suitable preselector.
This means that these analysers can still compete with the traditional swept analysers that use analogue RBW filters (like the HP 8568B) when trying to detect very small signals near very large ones because the ADC can be protected from the nearby large signal by the preselector. Lower cost instruments with a digital IF won't have this suite of preselectors and the ADC can easily be overloaded by signals many MHz away.
The old Agilent E4406A is a bit of an oddball because it has a very crude frequency plan that compromises the image and IF rejection. It was never meant to be used as a spectrum analyser and was meant to be used under controlled conditions to look at commercial transmitters used for mobile phones etc. I think that's why it says 'Transmitter Tester' on the front panel. This was probably Agilent's way of justifying the oddball frequency plan it uses! The E4406A should have a similar suite of preselector filters ahead of the digital IF but the E4406A only operates in FFT mode (not swept) so the benefit isn't as great.
I've still got my E4406A and still use it now and again. I bought the version with the 14 bit digital IF which was important to me at the time.
|
Re: HP 140B LVPS -12.6V Not Working
I've been cross-checking the board against the schematic.? I thought I had the dot convention correct (emitter) but then the differences between a few of the transistors on the board made me realize something didn't match so I need to be even more careful if I end up needing to replace those.
I'm just glad wires don't have dots.
Thanks,
Barry - N4BUQ
I would've guessed that the dot marks the collector. At least that
was the convention used on all the parts I encountered as a kid. The
literature of the day often referred to "the collector dot". But of
course that doesn't mean that other companies/countries followed
that convention, so I'm curious: Are you just guessing (say, based
on a quick DMM diode check, in which case you're rolling the dice),
or did you cross-check with some circuit-tracing against a
schematic?
And if you're talking about a TO-92, there is no standard pinout.
Parts of US design generally follow EBC, UK parts often follow CBE
(making it easy to swap with US parts by simply installing the other
way around), Japanese parts are frequently BEC (I've also
encountered ECB), but "generally" does mean "not always" here. You
have to check, don't assume.
Tom
--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070
On 4/22/2024 3:38 PM, n4buq wrote:
Something about this is confusing
me.? Looking at the board, the transistors and diodes all have
a dot at one lead.? I was thinking that dot indicated the
emitter and for some transistors, that holds.? It agrees with
the 2n3409 I replaced and most of the metal-hat transistors.?
With the flat of the 2n3904's TO92 facing me, left to right is
EBC.? For Q484, though, the diode across BE (I can't read it
very well but I think that's CR485 or CR486) is connected to
the center lead and the right-hand lead (facing the
transistor's flat).? Do those not follow the same convention
as, say, a 2n3904?? I'm used to either EBC being left-to-right
facing the flat or, possibly, B on the left or right, but this
is puzzling to me.
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If it helps promote how good these MXA analysers are, there is a nice hardware feature in the IF section of the PSA and the PXA and MXA analysers that helps when making critical dynamic range measurements.
There should be a suite of IF preselector filters that limit the bandwidth that the digital IF is exposed to. On the PSA, this means there is a lumped or crystal filter that gets selected to provide this preselection automatically based on span/RBW settings. I don't know how many IF preselector filters there are in the PSA but there are also a few preselector filters like this in the PXA and MXA. The IF bandwidth can be adjusted from a few kHz up to about 1.8MHz or so by selecting a suitable preselector.
This means that these analysers can still compete with the traditional swept analysers that use analogue RBW filters (like the HP 8568B) when trying to detect very small signals near very large ones because the ADC can be protected from the nearby large signal by the preselector. Lower cost instruments with a digital IF won't have this suite of preselectors and the ADC can easily be overloaded by signals many MHz away.
The old Agilent E4406A is a bit of an oddball because it has a very crude frequency plan that compromises the image and IF rejection. It was never meant to be used as a spectrum analyser and was meant to be used under controlled conditions to look at commercial transmitters used for mobile phones etc. I think that's why it says 'Transmitter Tester' on the front panel. This was probably Agilent's way of justifying the oddball frequency plan it uses! The E4406A should have a similar suite of preselector filters ahead of the digital IF but the E4406A only operates in FFT mode (not swept) so the benefit isn't as great.
I've still got my E4406A and still use it now and again. I bought the version with the 14 bit digital IF which was important to me at the time.
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! :)
--
Prof. Thomas H. Lee
Faculty Co-Director, SystemX Alliance
Director, Stanford-Samsung Research Initiative
Allen Ctr., Rm. 205
420 Via Palou Mall
Stanford University
Stanford, CA 94305-4070
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On 4/22/2024 4:21 PM, Peter Gottlieb wrote: That's known as improving your image!
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Jeremy Nichols
Dave McGuire