TSP #25 - Teardown and Repair of an Agilent E4421A Synthesized Signal Generator

[@EEVblog]

I don't have nearly the luck you do with faulty ebay gear! That's a nice score and an easy fix in the end.

[@gamccoy]

I enjoyed the video. Hats off to the original engineers that placed those indicators on the motherboard, too. It's nice they took the time to put those breadcrumbs in there for us. And as always, I appreciate the time you took to describe some of the theory.

[@ToniT800]

BTW Shahriar. I want to thank you! Your troubleshooting/repair videos helped me to do my first repair in my life on HP 33120A function generator. I also purchased it from ebay "as is" and the output was always on -17 V. But i didn't panic=) I just remembered how you fixed your equipment with step by step procedures, and it worked:)

[@TheCrazyInventor]

I love watching your troubleshooting videos. I have some old scopes lying around that need fixing. This video really motivates me to get started!

[@Thesignalpath]

CAT-scans are free! ;) At Bell Labs my research is focused on mm-wave integrated circuits design for wireless and wireline communication.

[@0PAIx]

Good to have you back. I have been regularly searching for new video offerings and insights from you. I don't always fully understand the detail, but follow the principles and learn a little more than I knew previously. I particularly like your episode balance where you have a lab experiment to demonstrate in the second half of your video. Thank you - Ian

[@bkupiec]

Teardown, repair, and tutorial all in one concise video. Your channel is one of the best!

[@DJSolitone]

WOW Shahriar the wait was worth it. This video is simply amazing (as usual), but you are getting even better!! I think my cat could understand your repair process. In bonus thanks for the Darlington mini course. Just perfect. You just Rock!!! Please come back to us with more videos!! You deserved the glass of wine!!

[@spacewalker3519]

I enjoyed this video for sure. I started working in the repair industry a couple years ago. For me, the most interesting work is testing and troubleshooting. So, seeing the steps outlined here that eventually led to fault isolation was very educational. Next time I see a power rail getting clobbered, and i know it's not the CCA's, i'll apply a some various currents to test the integrity of that line.

[@KeenanTims]

We appreciate it Shahriar, thank you for your in depth analyses, they are certainly a substantial and useful contribution to many wannabe EEs like myself. Can't wait for more videos!

[@964tractorboy]

Very good news to see another offering to the usual high standard. Thank you for giving up so much of your time.

[@nikoladivic2786]

Thank you verry much.I am not on your level, but your explanation is so simple and logic that I learn every time something .Best teacher , regards from Croatia !!!!!!!

[@capriracer351]

Another excellent video. I did not realize that Bell labs was still active. I am glad that they are, many great things have come out of that building. They definitely have one employee that is quite impressive, for certain. Keep up the great work.

[@Thesignalpath]

I hope so too. The block diagram and functionality is very similar to the other synthesizer I have repaired. You can find that episode on my channel.

[@WhitentonMike]

Good video. I'll have to admit, I was waiting for smoke when you supplied 9V to the circuit. I'd have wimped out and just replaced the TIP122 without trying to supply the 9V. Nicely done.

[@Thesignalpath]

You have to be patient. It is always risky to buy broken equipment. Also, you often need working equipment to fix the broken ones! Start with the basics, save up $1500 and you can easily start a nice lab with that. Choosing your words carefully when explaining something scientific is extremely important. This is something that I always emphasized to my students as well.

[@ggattsr]

So glad you are back with more great videos. Thanks so much for sharing your incredible knowledge in a way that makes it easy to understand. Anxiously awaiting the next one.

[@nemanjatodorovic2803]

Finally! Every day I check your channel. You have a very good channel, very informative, very useful! Thank you!

[@sdscotto]

Welcome back. Always glad to see a new video from you, Alan, Mike and Dave.

[@shaqywacky]

Look at all those screwdrivers on the top right at 34:35. That's the most beautiful thing I've ever seen.

[@youpattube1]

Following along as you solve the problem is a blast.

[@gregoberfield]

Big thumbs up - especially for the glass of wine at hand towards the end. :)

[@Thesignalpath]

ASICS also fail of course as well as processors. Unfortunately, in those cases, there is not much that can be done unless a replacement component is available. A while back I bought a broken Agilent scope and found out that the main ADCs were bad. I essentially had to throw it away.

[@vex9060]

Really nice repair teardown tutorial, I learned some good things from it and your explanations. Keep posting we need channels like this!

[@PY4SR]

Thanks for this excellent video, Shahriar. I have the E4400b and I believe the schematics. I'll check and send to you. I have to join my buddies: please stay on, your videos are always very expected.

[@DJSolitone]

HALLELUJAH Shahriar is back!!!!!!! That's some good news!!!

[@hpux735]

Great to have you back! Your videos are my favorite! I wish I had the confidence to invest in broken test gear.

[@1903A3shooter]

That was fun watching, love the cat scan. Dave

[@snipersquad100]

Great fix, Nice to see you back.

[@NerdNordic]

Aweeeyah! I have missed your videos Shahriar!

[@LevonAvagyan]

Apres Shahriar! Please keep doing great videos!

[@Dimlowuk]

Glad your back. The internet was getting boring.

[@SirBunghole]

The "Cat" scan did it for me! Well done!

[@dahappiehippie]

This was really great!!! I wish there was more quality content like from you, Dave and Mike!!!

[@Hatimoooo]

I just discovered this channel from EEVblog. I really like it. Good job!

[@Thesignalpath]

Thanks Dave! I have had my share of bad luck also. I think it is unavoidable. But this was definitely a fun fix!

[@CoolMusicToMyEars]

A good find, I always enjoyed repairing test equipment as deputy head of a NAMAS - UKAS test laboratory, I noticed Agilent changed from giving out diagrams & supplying block diagrams on most of their new test equipment some time ago, when it was HP it was very detailed diagrams, most Agilent is made in Malaysia these days on test equipment, it's still a good company, but I have a preference for the old HP equipment being of that era, Thanks for putting it on, I enjoyed the video and a heads into a unit I not seen before.

[@distancelab2010]

So interesting, and thanks for the explanation of how a darlington device works and how to use them. Thank You :)

[@corntragic]

your videos are awesome. I am studying for my BS in EE, I really appreciate your work!

[@srscricket]

I'm glad to see another video from you!

[@SeanBZA]

The darlington will benefit from a heatsink on it in addition to the PC board it is on. You can get ones that will screw to the top of the TO220 case and will have a thermal resistance of about 22C per watt, which will make it run cooler. It probably overheated in use with marginal airflow.

[@nashme11]

Man I was having withdrawals welcome back.

[@FennecTECH]

47:34 now THAT meter is a blast from the past

[@urbandiscipline88]

Thanks professor Shahriar, I enjoyed your video, and learned something. I always enjoy your videos.

[@josebarrientos5191]

awsome vids!! Thanks watching you troubleshoot helps me learn alot.

[@ourplesoop]

Ah you must love it when a repair goes that smooth. Shame about the shipping damage. One thing though, I wonder if the TIP device will fail in the future. It seems like a fair bit of power to be dissipating...

[@friedmule5403]

29:20 Thank you so much, I have never understood the basic logic in a Darlington pair, Yes I did know what it did and it got used, but the real understanding have I only got now, thanks to you!! :-) 30:31 and phase shift, I do now know what is happening, it's a delay in the signal! 40:38 I am assuming the reason for you not using "remote sense" is due to lack of space for one more probe? :-)

[@makutingting]

Thanks for the great video. I learned a different approach of injecting power from an external source to a known bad point in a circuit (without removing any of the components suspected to be causing the problem). Is this always applicable when isolating power supply problems? Isn't it dangerous at some point ? - But then, I guessed you've already assessed that given your level of expertise on electronics & electrical principles, you just know your stuff very well. Keep up the great work!

[@Thesignalpath]

Bell Labs is very active! :)

[@GaRbAllZ]

Great work and a very impressive lab!

[@Thesignalpath]

Thanks! Much appreciated.

[@MrPBrane]

Thanks for another great video! Though I would of course like to see more of your videos, I actually prefer few videos of high quality over publishing more just for the sake of it. Keep up the good work!

[@MeiklesAndDimes]

Love these kind of videos!

[@iknowsstuff]

that's some darn impressive guts in that sucker, lm317 fail in the same way, perfect voltage when open but it drops to near nothing when under load. Im amazed that a piece of pro kit like that was not fixed by those using it since they should have the skill to fix it!

[@flanlemonjello]

Thanks so much - your channel is a significant and wonderful part of my online electronics experience :-) +1 for a victory glass of wine

[@RoSi4You]

Great job. I can't wait for the other videos :)

[@tariqmehmood4955]

Mr.. You are a Gem of our world. Keep it up Sir 😊

[@Razor2048]

Awesome video, please keep it up and hope to see more videos :)

[@DogsBAwesome]

that was really interesting, glad you got a result

[@BrookeHedrick]

Wow! This was an excellent video. Thank you.

[@opablo_gm]

I'm extremely happy to see you come back to making these great videos... THANKS... (I'm not an academic nor a professional... I'm a hobbist and I learned a lot from your videos)

[@hitechespresso]

Awesome! a valuable machine saved for 61 cents!!

[@Thesignalpath]

Thanks! By the way, what is the circuit of the IC in your profile photo?

[@RandyLott]

I'm always excited to see when you've uploaded a new video. I always learn a lot and enjoy your extremely accurate terminology. I can tell you make a great effort to ensure the correctness of your wording. Do you have any advice on how to search for test equipment while under a tight budget? I'm new in the field and I wish to get some good quality, used equipment.

[@emd6456]

Excellent video, thank-you.

[@WisdomVendor]

Awesome vid dude. Very informative and enjoyable. Cute cat too. I also have a Russian Blue and he is constantly dead in the middle of what ever electronics I'm fooling with.

[@tiredfingers99]

When you attached the exterior 9 volt supply did you consider using a fuse or limiting the current supply because possibly one of the modules may have drawn a lot of current at one time? Thanks for a great video.

[@98505177229850590818]

It would be great if you make series on how to use these instruments like synthesizer spectrum analyzer RF generator power meter splitter attenuators etc

[@RandyLott]

Thank you Shahriar. I have an entry-level oscilloscope and logic analyzer. Do you think it's important to invest in a brand name power supply? I've always liked Agilent/HP units, but they're very expensive! Even the lowest cost Rigol unit is quite a bit, but it looks very appealing!

[@Sixta16]

Lovely cat and easy repair!

[@VahidShirvani]

I enjoyed watching this.

[@98505177229850590818]

The way you decide darlington pair is used for regulator makes you different .. it’s coming from experience .. Great repair I would never have guess darlington pair is used for regulation .. I would have got confused for so many parts and you don’t have even schematics

[@amtpdb1]

Great video. I want to learn electronic and want to buy an oscilloscope. How about doing a video on what to look for in them on EBAY and what type of fixes would not be too hard to either repair or have repaired. Thanks for the video.

[@tectalabyss]

Thank you very much for this interesting and informative video. Much respect to you Sir. I'll be looking for more from you. Liked, Tweeted,Favored.And added to Playlist. You Take care. Tec

[@ObviousSchism]

Cats of Engineering!

[@wadehicks9270]

That was a cool repair 👌👌👌👌👌

[@redshift78]

Wecome Back!!!

[@vex9060]

welcome back!

[@mickm7608]

Very good video. You should scrape off/remove the heatsink compound or pad. It was probably dried out and caused the failure. You seem very lucky with broken eBay stuff, broken off cap, bad $2 transistor etc. Mick M

[@jdennee]

WOW, this is so inspiring!

[@DavidLeeMenefee]

Thumbs up. Nice video that's well explained.

[@mikeselectricstuff]

You should send a still to Adafruit's "Cats of Engineering" page

[@xDevscom_EE]

Good repair, wish it could go always as easy as this :). And thumbs up for Darlington theory, it gives video more value then just tear down and replace parts stuff. Also how you handle cat around all that lab gear? Don't u afraid some hair get into all that precision expensive gear and cause problems? Maybe that's why all your lab is so clean and organized :D

[@DaveCurran]

Very interesting video, thanks.

[@hdmalpas]

Very nice video keep up the great work and it is very much appreciated. all the best.

[@OneCoolDude08]

The image originated from the USC - Viterbi School of Engineering website. They have it in high res 1373 × 1248 pixels

[@Nikkuuu69]

Hahah I lost it when I saw the cat sitting on a ~6K spectrum analyzer :') be aware of ESD!

[@douro20]

A DSP? The 68332 has lots of functionality for measurement and control, but I see no mention of a DSP in the spec sheet.

[@skycarl]

Really good,,,thank you.

[@Afrotechmods]

kitty!!

[@anmingren8747]

purely gold

[@vaualbus]

at the end you haven't describe how the sytetizer work and you haven't show us the block digram. I wish that the next repair video wouldn't be a psu problem. It happen twice that on interesting equipment the problem is the psu! Goo video.

[@radoinc]

...and you can see the 100MHz peak right there under the cat's butt :) Great stuff, thanks!

[@DanielRowe]

Thanks heaps!

[@TheJennetteFan]

HE IS ALIVE.

[@AureliusR]

Whoa, whoa whoa, if FedEx dropped my package and damaged the contents THEY would be paying for repairs, not me!!!!

[@BruceNitroxpro]

Aurelius R, I hope you were right about that.

[@ToniT800]

You alive??! Great=)

[@atw4321]

Well now i know who to contact when i have a problem mine 😅i have the ESG-2000A

[@vaualbus]

also how much you paid this item on ebay?

[@90chevytruck]

Its been a while!!!