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E4401B No 50MHZ Cal signal

 

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Nope.? While the scope functions with the cap removed, putting a good replacement back in reproduces the failure.? I suspect that the cap is part of an attenuator/filter.? Removing it is raising the test signal high enough for it to get detected during the alignment procedure.? Running without the cap, I notice that the noise floor is higher than it should be, and that changes to levels of the input signal do cause corresponding changes in display on the spectrum analyzer.? This is telling me that the gain is still too high in the IF stage.

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My current theory is that the front end is blown out and I will need to replace some component in the 1st mixer or amplifier.?? I suspect that the 50MHz test signal is present, but too low for me to measure with current equipment.? Which component(s) are blown at this point is the question.? Next steps are to probe the 1st IF, which I currently don’t have any suitable equipment to measure.

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I have ordered a LimeSDR which is supposedly capable of measuring up to 3 GHz to use as a stand-in spectrum analyzer.? I know it’s not a calibrated spectrum analyzer, but I am hoping it should give me enough to check relative levels and presence of the IF signals.? I will also be ordering a 54701a active probe today.?

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This whole process has been a humbling experience.? I’ve got lots of experience with lower frequency gear – oscilloscopes, DVms, radios, etc.? These spectrum analyzers are a very different beast and require very different troubleshooting and probing techniques.

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-- Mike

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From: <[email protected]> on behalf of "Mark Bielman via Groups.Io" <mbielman@...>
Reply-To: "[email protected]" <[email protected]>
Date: Monday, April 15, 2019 at 10:49 AM
To: "[email protected]" <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] E4401B No 50MHZ Cal signal

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Mike - The cap (C448) was not the problem? Rats.

 

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Typo:

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That sentence should read:

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? Running without the cap, I notice that the noise floor is higher than it should be, and that changes to levels of the input signal DO NOT cause corresponding changes in display on the spectrum analyzer.? This is telling me that the gain is still too high in the IF stage.

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The change that I see in the spectrum analyzer are a multiple of the change at the input.? – A 10 db change in the input results in a displayed 20 db change in the SA.? I also see a lot of harmonics of the 50MHz test signal when input is set to the internal 50MHz signal.

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-- Mike

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From: <[email protected]> on behalf of "Michael Williams via Groups.Io" <mike@...>
Reply-To: "[email protected]" <[email protected]>
Date: Monday, April 15, 2019 at 11:02 AM
To: "[email protected]" <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] E4401B No 50MHZ Cal signal

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? Running without the cap, I notice that the noise floor is higher than it should be, and that changes to levels of the input signal do cause corresponding changes in display on the spectrum analyzer.? This is telling me that the gain is still too high in the IF stage.
 

Without reading through all of this again... you have a decent scope, correct? You should be able to measure the 50 MHz cal signal with that. (around 20 mV or so) And also follow its path.
I have yet to see problems with the front end on these but I'm sure it happens.

I also have (more than one!) SDR used as a spectrum analyzer for signals above 3 GHz. (I have E4402 & E4403) They will work BUT if you do not know the frequency of interest they can be
pretty slow. (say sweeping from 1 to 6 GHz)

Mark
 

But if the C448 cap had failed short as you stated, at least it certainly would be part of the bigger problem.
 


?Alex,
Artek has the E4401 CLIP, which also covers the E4411B.? (Dave should really modify his search to let E4411 searches find that.)
Keysight has a free pdf of the service guide for the E44xxB series.? Search Keysight Support for "E4411B".? The service guide part number is?E4401-90474
--John Gord


On Mon, Apr 15, 2019 at 08:01 AM, Alex wrote:
On Mon, Apr 15, 2019 at 07:43 AM, ArtekManuals wrote:
The CLIP stands for "Component Level Information Package" Beginning in
the 1990's ( for the most part) HP/Agilent stopped publishing what we
all used to know as full up service manuals. At that point in time most
of the service manuals only? had test and adjustment info but not
schematics , no board part locators nor parts list . For roughly the
next 10 years if you wanted schematics you had to purchase a CLIP ( at a
price of $250-$500 !!!) . Trouble shooting trees as we knew them
disappeared all together for the most part . After 2000 they even
stopped ( for the most part) publishing the CLIPS. Typically CLIPS do
not cover GHZ level RF circuits, YIGS etc. Most do not cover the power
supplies and CRT ( or LCD) display units both of which HP had stopped
making and were 3rd party drops ins.

Dave
manuals@...
--
Dave
Manuals@...
www.ArtekManuals.com

Thank you Dave.

Do you have anything available for the 4411B in terms of service aid literature?
Maybe its time to make another purchase from you.
 

Mike...
I have a standard 50 ohm E4401 and the 50 MHZ harmonics do stretch out to 400 MHZ, so unless you are seeing a lot more, it would be normal.

John
 

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Thanks for the info, John!

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From: <[email protected]> on behalf of "jrann1 via Groups.Io" <jrann1@...>
Reply-To: "[email protected]" <[email protected]>
Date: Monday, April 15, 2019 at 2:31 PM
To: "[email protected]" <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] E4401B No 50MHZ Cal signal

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Mike...
I have a standard 50 ohm E4401 and the 50 MHZ harmonics do stretch out to 400 MHZ, so unless you are seeing a lot more, it would be normal.

John

 

John,

Thanks for the info and with the part number I was able to get the service guide PDF. I also found a section at the KO4BB website with lots of E4401B manuals, which I am sure most of you already know about, but just in case here is the direct link:



The trick was definitively to search for E4401B instead of E4411B and/or the specific manual part number.
 

Also came across a reference to a CD-ROM with documentation. Anyone know about this and if it might be useful?

Agilent Technologies ESA Spectrum Analyzers Documentation
CD-ROM Part Number: E4401-90427?????????
?Date: August 2002

Info came from this PDF document which contains links but the corresponding files seem to have been removed from the site.
http://doc.xdevs.com/doc/HP_Agilent_Keysight/HP%20ESA%20E4400%20Series%20Documentation/ESA%20%28D%29/MAINMENU.PDF
erie patsellis
 

Have?you tried the link at archive.org? I’ve had some success in the past using that approach.?

Erie




On Tuesday, April 16, 2019, 9:26 AM, Alex <hpagilentgroup@mi?

wrote:

Also came across a reference to a CD-ROM with documentation. Anyone know about this and if it might be useful?

Agilent Technologies ESA Spectrum Analyzers Documentation
CD-ROM Part Number: E4401-90427?????????
?Date: August 2002

Info came from this PDF document which contains links but the corresponding files seem to have been removed from the site.
http://doc.xdevs.com/doc/HP_Agilent_Keysight/HP%20ESA%20E4400%20Series%20Documentation/ESA%20%28D%29/MAINMENU.PDF

 

Took a peek... this is old I think.
The manuals have been revamped since then.
The "new" ones are available via Keysight and cover the same material.
(updated to reflect new firmware versions)

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