Video Teardown, Analysis and Repair of an Agilent E4407B ESA-E Spectrum Analyzer

[Shock]

Thanks for the video, I was cheering you on there in the middle when you faltered, but you came through in the end and nailed it, well done.

Often when we sleep on it things become clearer. I think you have got the gear and the knowledge to never back down from a challenge now.

Don't worry about the length of the videos you can always throw some quick ones in. There is no harm in making them episodic, as long as we don't have to wait. 

[Hugoneus]

Very high performance spectrum analyzers are actually DC coupled and can measure down to 3Hz.

But they usually have a big downside: you have to be very careful when measuring with such an instrument as the input stage will be destroyed if you input a dc signal.

Yes, these instrument have a big label at the input connector warning the user that only 0-VDC is allowed.

[G0HZU]

If the 10dB (or more)  attenuator is selected I think the DC tolerance goes up to several volts but it isn't wise to chance this!

For my old 22GHz HP8566B I bought a high quality DC block (N type) that works from about 100kHz to 18GHz. It wasn't cheap but it does prevent damage from external DC.

At my place of work, the most common way that uW spectrum analysers get damaged is from external DC rather than from high RF power.

[all_repair]

When the content is there, length is not a problem.  Each and every video of yours, no skip or fast forward when I was watching with full attention.

[Hugoneus]

If the 10dB (or more)  attenuator is selected I think the DC tolerance goes up to several volts but it isn't wise to chance this!

For my old 22GHz HP8566B I bought a high quality DC block (N type) that works from about 100kHz to 18GHz. It wasn't cheap but it does prevent damage from external DC.

At my place of work, the most common way that uW spectrum analysers get damaged is from external DC rather than from high RF power.

Yes, this is indeed a problem in many places. While I was doing my Ph.D., another graduate student accidentally screwed an SMA into a V connector on a VNA. It was a thread-on-thread mess and the whole connector needed to be replaced. Another time, a student put 8V on the input of a 70GHz sub-sampling scope module, killing it instantly.

[dentaku]

I would be interested in seeing a video explaining PLLs.
If you haven't watched Alan W2AEW's video on PLL already I would suggest you don't so you're not influenced by his really excellent demonstrations then see how your method of explaining it differs. then you can watch the W2AEW video after you've done editing yours

[ivaylo]

Yes, don't change anything. Your videos are excellent!

[HighVoltage]

Another time, a student put 8V on the input of a 70GHz sub-sampling scope module, killing it instantly.

Thanks for answering my previous questions.
One has to wonder, why HP would not install a DC block at the manufacturing level.
Why is there even a DC input path open, if it is so dangerous for the instrument?

[Hugoneus]

Another time, a student put 8V on the input of a 70GHz sub-sampling scope module, killing it instantly.

Thanks for answering my previous questions.
One has to wonder, why HP would not install a DC block at the manufacturing level.
Why is there even a DC input path open, if it is so dangerous for the instrument?

Well, for the PXA/PSA with a 3Hz low-frequency limit, they have no choice. There is no way to meet 3Hz low cut-off and 50GHz high cut-off simultaneously.

As for the scope module, it has to be DC coupled, because it is suppose to measure DC offsets. It was just rated to only 5V and not 8V.

[vaualbus]

Do you know how on the new agilent/keysight spectrum analyzer can achive  a range from 3Hz to 50Ghz?
What could are the differences between the SA you bought and the new agilent models?
Best regards, Alberto.

[mhuffman77]

Bump on this topic. Any chance you could scan and upload the Schematic you are using. Schematic #E4403-60057? Great video, thank you very much for recording and sharing this. I watched it from end to end yesterday trying to repair an E4403B with an LO unlock failure. Unfortunately I received erroneous readings at the pretune circuit so we I had to part ways there in terms of failure. Pretty much dead in the water without that schematic.

[smgvbest]

Bump on this topic. Any chance you could scan and upload the Schematic you are using. Schematic #E4403-60057? Great video, thank you very much for recording and sharing this. I watched it from end to end yesterday trying to repair an E4403B with an LO unlock failure. Unfortunately I received erroneous readings at the pretune circuit so we I had to part ways there in terms of failure. Pretty much dead in the water without that schematic.

Don't know if you're still needing the E4403 schematic but ebay has scanned copy
eBay auction: #https://www.ebay.com/itm/HP-E4401B-Component-Level-Info-Package-Schematics/390129973036?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

or order direct
http://artekmanuals.com/manuals/hp-manuals/

[mbielman]

Our E4407B at work developed an "LO Unlocked" error and decided to take a look. I have repaired two ESA's with this problem, same IC as in Signal Path repair videos. But when I started looking at the RF Deck PCB, it's different! Labeled as p/n E4403-20100. The divider chain has different parts. Uses an Agilent 1GC1-4210 divider (similar to HMC862) divide by 2/4/8/16 I believe, selectable via 3 inputs. It's driven by a differential receiver/driver MC10EL16.

CANNOT find a CLIP for this one!

But the MC10EL16 has 0 dBm coming in, and -15 dBm coming out.
Looks suspicious!

Mark

[mbielman]

Correction: I think E4403-20100 might be the blank PCB.
The label on the PCA is E4403-60107. But NOT in the CLIP.

Mark

[DavidAlfa]

Does anyone where to find the schematics shown in the video?
Can't understand why he didn't mention the transistor reference anywhere in the video? (”Thanks Twitter" isn't).
Thankfully I found the thread pointing to a EXCELICS EPA025A-70 part.

https://twitter.com/m0wut/status/1561824996204371970?cxt=HHwWhICzweTj26wrAAAA

https://twitter.com/m0wut/status/1554191138965393409

[anotherlin]

Does anyone where to find the schematics shown in the video?

Try artekmanuals.com, but it's not free. They have the component level manual for E440xB.
I've not tried for that model in particular. But I've bought quite a few manuals for Tektronix plug-ins, the scans are really excellent, worth the money.

[vaualbus]

Indeed it would cool to have his copy too as his version apparently were digital all the time, the artekmanual version is the scanned manual.
Note the artekmanuals now is a little bit slow as the owner just recently passed away.
Them business is now handled by his wife but for now only the bay store is handled due to IT problems apparently.