Вставка
- Опубліковано 21 лип 2024
- In this episode Shahriar repairs an Agilent N9020A MAX Spectrum Analyzer. The instrument is well equipped with real-time capability and direct I/Q input ports on the front panel. The instrument does not show the correct signal levels and fails internal calibration.
After a brief teardown, the block diagram of the instrument is carefully examined for potential failure points. It is determined that front-end switch and mechanical attenuator is likely faulty. Teardown of the unit reveals significant damage to the attenuator due to some high-power at the input. Unfortunately, this also implies that the front-end RF selector and pre-amplifier modules are also damaged. In the second repair video, the front-end module is disassembled and damage to the dies can be observed.
Luckily, a relatively inexpensive front-end (SSLAM) unit is sourced from eBay and the repair is completed. The performance of the unit is verified after the repair and the front-end I/Q input functionality is demonstrated.
The Signal Path
www.TheSignalPath.com
/ thesignalpath
www.Patreon.com/TheSignalPath - Наука та технологія
Studies have shown that being supervised by Dr.Pooch during a repair or experiment increases the chances of success by up to 303%. While on average the chance of failure of any kind is significantly decreased, certain specific failure modes become more likely under supervision by Dr.Pooch, most notably cat-astrophic failure. (I'm here all week...)
That is such a dog-ma :-)
Cat in thumbnail, definite watch.
No electronic repair is ever done without a full CAT scan :)
I love the way you document your approaches to troubleshooting and problem solving. Thanks for taking the time to put these videos together!
alright, I just dialed in, because of your famous cat sitting on top of these incredible measurement instruments ! Great cat ! And great videos, of course :-)
Ah, I found her, at 9:05 minutes :-)
Just found your channel and have spent many evenings watching your videos. Very educational and interesting. I really like the in-depth analysis and repairs of the RF instruments! Watching and learning here have made RF stuff seem less intimidating. Thanks, and keep up the good work!
Amazing troubleshooting approach. Thanks for yet another awesome educational video.
Came for the cat. Stayed for the teardown
Great video! Thanks for sharing and lets hope you find the replacement parts!
came for the eduCATional content and I did not get disappointed
Thank you!
another great teardown and troubleshooting.
Thank you for your hard work to include us on your repair journey, I think your explanations and logic in tracing the problem help me and others immensely. I do how ever take offense to your depreciating view of the project supervisor. Can you imagine the trouble your could get into without his valuable experienced supervision??? Again mahalo nui for the video and your time..
A repair failure video?
What is this - EEVBlog?
:)
Common he nailed the problem ... just an issue of sourcing spares
Savage.
What I am often interested in is the nitty gritty details that set apart a SA starting at 2Hz from one starting at 100kHz
FE-5650A OPTION-58 RUBIDIUM FREQUENCY STD for sale on eBay now :-) I know you've been saying how much you'd like one for your lab....
Maybe insert another electrical attenuator in the path to do just the 0/2/4 dB attenuation ? i.e. use the existing one for input switching & AC/DC coupling, but force it to 0dB, get the control signal for the attenuation control and route that to another attenuator. I think pure attenuators without the input switch and ac/dc are easier to find.
I do videos fixing test gear, but this is well beyond what I do, I am always very impressed with your knowledge and content.
and your videos are beyond what I can do.Thank you both
Very cool to see the thought process on sourcing the problem. I wonder if the crack was caused from the solenoids banging on the ceramic too hard or too often. The resistive element that was destroyed looks as if too much power was injected... maybe. :-/.
great job
I got three Agilent 1156A which might be compatible with that spectrum analyzer. Bought them from an auction.
Nice video
Another thought I had, wouldn't it be possible to replace the complete attenuator/switch assembly by a bunch of coaxial relays and some SMA 2dB attenuators?
The only thing that wouldn't be super easy might be the adaption of the control interface but even that should not be too hard.
Greetings again,
Michael
I have a Yellow Pages you can use to fix it with. Works fine with everything else. Little bit of concussive maintenance and she'll be right.
Jim Griffiths, Yup... like Momo Motors story of Alfred Momo fixing a rough running Ferarri with one blow from a small hammer. The car owner questioned the bill as "excessive ($1000) for one hammer blow." Momo replied, "I only charged $1 for the hammer, $999 for knowing where to hit it."
Nice videos, thanks! Do you have any tutorial video or PDF on how to measure FM receiver selectivity ?
I would totally buy an antistatic towel :3
Solder some SMD resistors over the gap and it'll be good as new!
Just put in a 0603 instead so it can handle the power and I´m sure it will still keep the 50 Ohm impedance from 10Hz - 8.4GHz as well so that should be a cheap fix.
I doubt this would work, but it would be an interesting experiment! Although you can see the frequency response curve in most datasheets and it's far from linear. Search for "Vishay Frequency Response of Thin Film Chip Resistors".
@@ligius3 I was of course joking, I thought that was very obvious.
It will of course not keep any 50 Ohm impedance over any 10Hz to 8.4Ghz and at the same time keep its resistance value constant all the way. these chips are custom made specifically for this so nothing else will work as good or even at all and no commercial SMD resistor would even be remotely close.
@@dtiydr You'd be surprised. The return loss spec is 20dB below 3.6GHz and 15dB below 8.4GHz. The garbage-tier terminator I made before I had a real cal kit evidently comes within 3dB of that with 0805s and no attempt to flip-chip or distribute the loss (I just swept it). I'd bet Shahriar could get the machine entirely in-spec with 0201s, flip-chip, and rough geometry matching (several in parallel to match the width of the main trace). That said, these are the very frontmost pads in the entire signal path, so I understand completely if he wants to do it right.
I once did a telecourse and the middleware required you to install Adobe Reader. It couldn't be any other PDF software. For that reason I set up a dedicated computer.
Great! Watched this with pleasure
What was the name of the channel?:
The Analyses Path?
👍👍
Interesting failure mode, it’s hard to imagine what caused the fracture, unless it was dropped... Hope you are able to source a replacement, very nice instrument.
At that size I would imagine that thermal shock could damage the ceramic substrate, as seen in the microscope.
I would hazard somebody transmitted RF into the unit, and was using the 60dB attenuator settings to see the signal, forgetting it is very much energy limited input wise, or they forgot to put in the inline 60dB attenuator/dummy load before use.
@@SeanBZA I intensely dislike somebody :-)
Any video with a cat in it is a good video. Now I watch.
Btw, what kind of breed Pooch is? Is he a russian blue?
Why your audio volume is so low? It is intentional?
9:07 . . . I came here for the Chartreux Cat . . . named Schrödinger ?
May I suggest Sumatra PDF reader
I use Sumatra almost every day, very good and lightweight reader, not that bloated Adobe cr*p. But can you do annotations with Sumatra?
Where is the kitty? I want to see the kitty. Ooh nice analyzer... but where is the kitty?
searching for agilent 33360-60003 on usual sources like ebay, there are a few listings for prices around 300-500 bucks used or 700 bucks for new ones.
Probably best to find 3 or for for $59 that are "for spares or repair, or another unit that uses these attenuators, but which is massively damaged elsewhere, like having had a power supply burn out.
Liked just for cat content.
I would have liked for technical content anyway :)
@The Signal Path do you teach courses in your professional life, just wondering?
I think he did, not sure if he still does it. I think it goes like this: professor assistant -> research scientist -> Black Mesa engineer (we are here) -> Gordon Freeman
@@ligius3 And that on episode #143. Thats 1+4+3=7. 10-7=3 => Half Life 3 confirmed
Yes, I am an adjunct professor at Columbia University in NYC. But my main job is at Bell Labs.
@@Thesignalpath I studying electronic-ICT myself and doing a master thesis involving microwave design (Rotman lens and/or Butler Matrix). If it wasn't for you video's I probably would be doing this thesis. Thanks for your excellent quality show and keep it coming. PS any video's on Rotman/Butler in the pipeline? ;)
@@nxt-1 Thank you. Rotman, Butler networks sounds like an interesting topic. Should make a good episode.
maybe you can buy two attenuators of 2 dbm packaged to-8 and place them to see if it works well
These chips are highly customized probably made by Agilent them self and these chips keep their 50 Ohm impedance from 10Hz - 8.4GHz and their exact resistance all the way as well as they are built to do and have an exact size and such as well, any commercial available SMD resistor or similar will not be even remotely close to do that.
@@dtiydr sure but the person you are responding to said attenuators, not SMD resistors.. Look at something like the ATN3590-02 or HMC652LP2E, seems to be very similar design to what is on the ceramic. But no idea if the spec is close enough.
@@jaro6985 Once again; whatever attenuators or SMD chip found those in the scope are meant and built for this scope and this scope only and any other chip must have exactly the same characteristics, as size, as the original chip has which no one will except the very chip it self purposely built for this.
@@jaro6985 ATN3590-02 seems to be to small for a direct replacement, but a hack with HMC652LP2E (~5 euros each) ... glued on the current ceramic scratch the old resistor from ceramic and bond the chip it. I will go for a try ... @TheSignalPath ?
No signal path vid is complete without Pooch :)
Pooch is yawning about this repair!
Your cat's name is Pooch? What's the dog's name?
What kind of hater gives this awesome video a thumbs down?...
Terrible.. ...its those kind of people that need sent off to their own island. Far...far away from the rest of us humans
christopher L Probably some robot or someone misclicked. Apart from that I don't think it even matters to youtube whether you click up or down, both add to the same counter of viewer engagement so to speak
The video is probably showing up when people search for cat videos... ROFL
I'm guessing dropping an 0603 or 0805 resistor on the ceramics won't work? It shouldn't change the characteristic impedance that much would it?
These chips are highly customized probably made by Agilent them self and these chips keep their 50 Ohm impedance from 10Hz - 8.4GHz and their exact resistance all the way as well as they are built to do and have an exact size and such as well, any commercial available SMD resistor will not be even remotely close to do that.
@@dtiydr Would be interesting to see how well it would work, Shahriar would have the instruments to characterize the 2db attenuators after such a "repair" but probably not the time for something like that.
Maybe with two 0402 resistors in parallel one could get decent results up to 3 or 4GHz at least.
@@s3sebastian Decent yes where high precision is not needed since it will not be linear all the way for sure, so with other words not even near whats needed for this instrument to work as intended even at that small range. And oh yes he would easily be able to test this, who know one day perhaps.
Everytime I see a Keysight/Agilent instrument featuring a seemingly-out-of-the-box Windows version my perception of the reputation of that brand goes down a bit more.
there's nothing like playing pinball on your VNA
The magic is not on the os is on the hardware.
@@pufero1 yeah, I know, but I still think that embedding a consumer grade OS into a lab grade instrument looks lazy and unprofessional. Being a top grade device for a top price, you expect a clean rock solid embedded OS, not a system cobbled to run games and office. Still my opinion though.
@@taldmd, I hear you. Sounds doable, but then you'll have version x of OS (?) problems.
at 19:12, 10 - 30 = 40... I believe it only if it comes out of your mouth! :)
Haha! What I meant was -10 - 30 is -40! :)
Wow can I have give away?
Just leave a comment on the previous episode. I will make the draw next week.