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In this episode Shahriar investigates a faulty Agilent 53152A 46GHz frequency counter. The instrument does not power on and shows no sign of internal voltage presence. Teardown of the instrument reveals a large PCB where all analog and digital circuity is contained. The power supply module is a module components and upon measurements shows no activity.
The power supply is a simple switching architecture with functioning input rectifier and capacitor filter. By using an oscilloscope it is clear that the power supply PWM controller attempts to start. However, the main power supply pin shows unstable voltages indicating inadequate charge retention on the rectifying capacitor. Replacing the capacitor revives the startup condition and the power supply function returns. The PWM controller and main switching transistors are also replaced with new ones. After this repair the unit powers on and passes all self-tests. The unit can successfully measure signal frequencies and power.
The Signal Path
www.TheSignalPath.com
/ thesignalpath
www.Patreon.com/TheSignalPath

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Опубликовано:

3 июл 2017

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Комментарии : 90

@winstonsmith478 7 лет назад

A $12,000 frequency counter for $650 and a few hours time to fix it. That's a real win.

@mikeselectricstuff 7 лет назад

Bad caps on the primary side are such a common fault on PSUs I usually replace them by default without even testing.

@Thesignalpath 7 лет назад

Yes, you are right of course. I was just all too eager to get to the frequency counter itself! :)

@EyalSoha 7 лет назад

Hey, spoilers! :-)

@TehMG 7 лет назад

Yep, most of the SMPS I've repaired either had bad caps feeding the driver IC or bad caps on the secondary side. Extremely common fault, and by my observations often the result of poor component placement. Many times when I find a bad cap in the supply circuit of the driver/PWM IC, the cap is located very close to a hot part such as a heatsink, power resistor, NTC, etc, which leads to the eventual failure of the capacitor. I've found this design defect in many power supplies even from reputable manufacturers. No matter how good quality electrolytic capacitors are, they all eventually succumb to high heat. Good design practice is to keep all electrolytics well spaced from heat dissipating components.

@TheRadioShop 7 лет назад

I think it is great that you take the time to show the troubleshooting on this type of repair. Most of the time when a instrument like this comes across the bench the first thing techs do is change out all the caps. In this case it would have solved the problem, but no one would learn anything. I do hope you can reach 100k subs. Like you said we have a small audience on these type of videos. Just over two years I and I am about to hit 5k. Thanks for all your work.

@rasz 7 лет назад

no, people that change all the caps already learned that its the caps that fail first.

@yasirnoori4848 6 лет назад

Shahriar, don't let the number of subscribers put you down, the quality focused contents you're providing make a greater difference to the community, so please keep going forward with this type of videos.

@DetrimentalScience 7 лет назад

The logo on the bottom side, bottom left of the silk screen almost looks like a flux capacitor. Never doubt that your videos aren't helpful for people that like it! It is hard to find this level of quality ANYWHERE else. Even though I don't have even 1% of your knowledge, I still learn a lot about problem solving workflow for more simple devices.

@AmRadPodcast 7 лет назад

Congrats on the fix. Nice addition to the bench!

@jonka1 6 лет назад

I think the number of subscribers is a reflection of the world we live in rather than your excellent content. Thank you for wanting to do this.

@DoRC 7 лет назад

30:00 The fact that in the beginning you said you couldn't be bothered to recap the board made me laugh... :)

@Thesignalpath 7 лет назад

Yeah... Oh the irony!

@alexreeve 7 лет назад

Haha, yeah i was like "oh-oh" when you said you wont recap... i sometimes say the same to myself... and end up finding a bad cap after alot of troubleshooting.. darn! ;)

@patriotik 7 лет назад

Thank you for making another wonderful video. Always great to see your new releases popping up.

@k1mgy 7 лет назад

Congratulations on this video. It exemplifies what happens when knowledge, experience, and a careful approach is combined. These are the kind of videos I find extremely helpful.

@JohnGotts 7 лет назад

It's neat to be able to look at test equipment that mere mortals like us never get to see. 46 gigs goes way beyond anything the hobbiest in 2017 would ever want, but as the march up in frequency continues perhaps some day applications in that frequency range will become more common. And great work on the repair. Just a five cent cap and a fan in the end.

@WillArtie 7 лет назад

Thanks again SS! Great video as always.

@nplanel 7 лет назад

Good work, so the hall effect sensor that you found come from the fan

@Darieee 7 лет назад

This was amazing ! Not to mention highly informational; thanks a lot !

@thekaduu 7 лет назад

Perfect! Thank you as always.

@JetNmyFuture 7 лет назад

What a unique piece of gear - so few people will ever need such a counter. Totally disabled by a single part. I had a failure on a high-end LeCroy DA1855A differential amplifier but the failure caused the PSU to pulse high voltage into the circuit, destroying the unit beyond repair. Look forward to seeing this used in some future video.

@stefanosmakris5641 7 лет назад

Amazing. Yesterday I finished repairing a SMPS with the exact same IC that had failed for the exact same reason! I wish that you would have posted this video a week ago and save me some time of troubleshooting! :-)

@Andrewausfa 7 лет назад

Excellent video. Thanks!

@DoRC 7 лет назад

Too easy. I keep waiting for a doozy of a repair but you are super lucky!

@kieranj67 7 лет назад

Thanks, nice repair job

@wattmeter 7 лет назад

most excellent. thank you!

@Narwaro 3 года назад

“Please be very careful ... I’ll set it to something non-lethal” Me, a Physicist who has already touched 240VAC multiple times and whose collegues measure exposed 2kV wires with the justification “I was being careful”: That’s cute :D

@freetoc1 6 лет назад

Excellent. thank you!

@heathwellsNZ 7 лет назад

Immensely interesting! Thanks!

@joes5669 2 года назад

Oh man. Keysight should be paying you big bucks. Every time I watch one of your videos I end up on their website!

@TSAlpha2933 7 лет назад

Aaaand subbed. Love stuff like this.

@octavmandru9219 6 лет назад

great explanation on the PS. Thanks! Maybe I can fix now mine

@adithyayuri 7 лет назад

great video ........ thanks ........

@ronniewilliams3420 6 лет назад

As communication tech I suspect the caps, resistors, check supply next, etc., just common sense stuff, I first learned in the US Navy. Yeah Go Navy. I always enjoy your videos ... :)

@dickpacincko 7 лет назад

damn capacitors get you every time.

@gbclab 5 лет назад

And what an excellent scope you have too! I've got today one HP 53150A with a primary fuse broken, now it is perfectly working, olny I have to check the fan operation...

@pa3deeghztv302 7 лет назад

nice video also nice counter keep it going....

@vaniz2012 4 года назад

Perfect

@jackm_ 7 лет назад

between you and the other easy fixes videos and topics, i just HAD TO byte the bullet ;) now i have a working four(three*) channel 500 MHz lecroy that i got for peanuts thumbs up :) *haven't had the time to troubleshoot and eventually repair the fourth channel

@TecKonstantin 7 лет назад

you probably already know but the Weinschel Planar Crown is supposed to have the ground inside, without you would get tremendous reflections. Normally they are pressed i and should not fall out. And yes they are rare but they are quite good because the impedance and parasitic of the spring contacts are really low. It also has some advantages because it will lock in rotations an so prohibits rubbing of the surfaces unlike SMA, APC7 and such. And you do not need torque wrench. They have a whole ecosystem around that form changing damaged connectors quick and easy, an also to have a common connection to adapt to any other standard. Maybe someone at Agilent design team had a representative from Weinschel convince them ;)

@funkyironman69 4 года назад

14:40 Although, if it did have power factor correction it'd boost the rectified voltage to ~400V DC. So it could be unsafe even though only 30V AC is supplied.

@AngDavies 2 года назад

Always a nice feeling when you happen to by luck guess one of the faults immediately :). (The pwm controller) just a visual inspection made me notice that little tiny resistor next to the chip was discoloured to the point that the bands where disappearing and I kinda drew air through my teeth and thought that ic is not going to have liked that is it :/ Really rather close proximity, but I guess it probably wasn't a problem when the fan was working. The second fault did seem very "capacitory" (failure under load).

@grahambernard3932 7 лет назад

Quality commentary. I got a wee bit lost around the logic flow. That's not you it's me and not having an advanced understanding of logic electronics. However, with your intuitive tuition on these aspects I'm sure I shall keep learning from you. Also, I enjoy your exclamations of success and the "beauty" statements and your "wonderment". Oh yes, I subscribed.

@CNe7532294 7 лет назад

Reminds me of a repair I did 2 months back for an old HP lead acid charger/inverter. Powered on but only with fresh battery. Charger wasnt working. Traced it to the unit's SMPS. Eventually traced it to the PWM chip Siemens TDA 4605 made by West Germany (unit is old). I also thought the BUZ90A Mosfet to be broken but it works. Turns out its almost the exact same issue here.

@AlexeiPolkhanov 7 лет назад

Wow this is a great repair video because failure was not so obvious. Just replacing all electrolytic capacitors without the analysis would have killed the entire plot. I have heard your short comment about the videos at the end. Please keep the videos long and detailed. I don't know about others but I often watch every minute of entire video with interesting DETAILED analysis like this and sometimes I do it twice. Short 10-20 min videos are just too boring and missing all the juicy details.

@PlasmaHH 7 лет назад

This is really the ideal thing to setup a lab: produce content, use the money generated by that content to buy stuff to repair, produce even more and better content, repeat until the lab is the best in the world ;) I wish I had time to do such a channel ;)

@ironman7261 7 лет назад

love the repair videos I think its foolish that high end counters like that would not come with oven controlled crystals as standard

@ufohunter3688 7 лет назад

Excellent video as usual. Thanks for sharing it. A side note @21:00: I would use a ~1K Ohm resistor between pin 12 and pin11 and apply + power to pin 11 only. This case, you are protecting the internal Zener diode (12mA Max @12V which is enough to run the chip, a 1/4 watt resistor should do) from over current (in case you apply say, 40V to the input "40v/1K= 40mA" will pass through the internal Zener diode). A low ohm resistor, will also act as a noise suppressor for the power supply. An additional ferrite bead in the path of Vcc ot Vc with do some good too. One thing is not clear to me. Do I need an actual R/C network on pin 7? Or can I apply my own buffered DAC analog voltage, or even an external clock instead? looking forward to your next video.

@KF7JO 4 года назад

$20 for a 46 GHz connector!?! What a steal!

@douro20 3 года назад

They tend to go cheaply because this interface is rarely used. It's a shame that it is due to the robust nature of the interface, which allows cables to be switched often without needing a torque wrench and minimises damage to expensive connectors.

@zvpunry1971 7 лет назад

Where did the hall-effect sensor come from? Maybe from the fan? Does that sensor still work? So many open questions. ;) I wouldn't install expensive frequency references in all these devices. I would prefer a good gps disciplined OCXO and a distribution system to get the 10MHz (and 1PPS) where needed. But even this would be expensive, but there are people who have built such setups with stuff like video distribution amplifiers and rubidium references from ebay.

@rhirsch81 2 года назад

Ten bucks says the mystery hall effect sensor fell out of the broken fan.....

@colinweiss5175 7 лет назад

Very nice video, thank you! I have noticed that the Counter has an input for an external 10 MHz Reference, as probably a lot other pieces of your testgear have. Even if all your pieces of test-gear have highly-accurate internal 10MHz references, would there still not be some amount of drift between them? Would it not make sense to set up a Lab-Standard 10 MHz Reference and fan that out to all the different pieces of test-gear? I'd be interested in hearing your thoughts. Cheers!

@ivanblogs 7 лет назад

I know it's drudgery, but consistent info in descriptions on your videos would be very handy. When you mentioned Patreon, I went to find and click your Patreon link in the description (I don't see any). You can guess what: (No description + No link) * No patience = ?

@HeyBirt 7 лет назад

I get a big kick out of your cat getting involved with your work. My cat likes to run off with bits of wire and get right in the middle of things. They sure make the workbench an interesting place.

@JustSomeGuy1967 7 лет назад

Have you been involved in Exalt or SIAE? Just wondering...I am a small WISP and over the last few years have built 40 mile hops with these two manufactures and am always intrigued how awesome these microwaves work. Watching your videos has made a lot of these thing more understandable to me...thanks.

@joopterwijn 7 лет назад

Thank, "Nice content" to use your own words :-)

@PlasmaHH 7 лет назад

Regarding the rubidium, would it not make more sense to get a really good one and distribute it throughout the lab into every unit that accepts external references instead of putting it into single units?

@jfrede1976 7 лет назад

I think a GPS disciplined oscillator for the lab would be appropriate.

@bsalai 7 лет назад

This is a little off topic, but where did you find the cylindrical supports for your shelves. My cinder blocks are sturdy but they take up a lot of space. Thank you for all the work, I have learned a lot. Brad

@garci66 5 лет назад

waaay too late, but those are from IKEA. I was using the same for a monitor stand at my office. They are nice since they are adjustable. That particular model might be discontinued, but the "CAPITA" ones are probably very similar: www.ikea.com/us/en/catalog/products/30263575/#/60263574

@gbclab 5 лет назад

As far as you know, are these stable measuring sine signals of low frequency like 1 kHz, 10 kHz, 100 kHz? Mine is very stable with 10 MHz but very instable with a 1 kHz sine wave signal, only stable with square wave signals.....

@senohpi 7 лет назад

I dont recognize the white RF testcables, what brand/model are they?

@EvanZalys 5 лет назад

Should that SMPS not be run with a load? I know some will burn up without a load... plenty just won't regulate.

@JimMorrison44 Год назад

Hi from Poland! Very interesting video, impressive, well-done. Can somebody tell me how much such Agilent, like here, working condition goes as for March 2023? Thank you.

@JGunlimited 7 лет назад

Is it possible to test whether a capacitor is good or bad without desoldering?

@PeterWalkerHP16c 4 года назад

The Bell Labs and Patreon is just a front, the real moneys is repairing gear to a couple of thousand percent markup !! :-)

@firedeveloper 7 лет назад

Any info from the IC that fell at the beginning?

@Thesignalpath 7 лет назад

Likely a Hall effect sensor from the broken fan.

@lordhelmchen100 7 лет назад

650$?? damn that was a great deal :D

@DaveMcAnulty 7 лет назад

Isn't the LoZ only for AC measurements? It don't load the DC line when testing with it, does it? Jealous 87V user here :)

@mcintoda9 7 лет назад

Why is the firmware split into even and odd bits on two chips?

@cmdstraker 7 лет назад

That little fan seems like an odd design choice. Even if it was working at peak efficency, how much could it actually do without an air duct?

@cncdavenz 7 лет назад

Maybe some cat videos would help with your subscribers :-) Again another interesting video. Cheers Dave

@m93sek 7 лет назад

Can I cook my noodles with this? How many watts does it have

@antoineroquentin2297 7 лет назад

Where could i get faulty lab equipment (to repair)?

@Thesignalpath 7 лет назад

I get pretty much everything from eBay.

@antoineroquentin2297 7 лет назад

Any particular keyword?

@materialsguy2002 7 лет назад

Two thumbs up! If I could spontaneously generate 1E5 subscribers, I would. That said, you are doing good work.

@gglovato 7 лет назад

Actually this was more a "HP PSU repair" and "partial teardown"(we didn't see inside the cans!). Also, ¿¿¡¡how come these devices do not use RPM-monitored fans?!?!, it's beyond my comprehension that these very expensive, very high end and very high-margin equipment have straight to VCC dumb fans(and it's not the only one, of all the teardowns i've seen in YT not one has RPM control/monitor)

@Thesignalpath 7 лет назад

I promise to show more of the unit when I upgrade it. :)

@SianaGearz 7 лет назад

Don't be so modest. If EEVBlog can have half a million subscribers, then you can have 100 000. But then, i think w2aew will hit it first, sorry :P

@OC35 7 лет назад

That white powder looks like it came from the battery.

@jonnysolaris 7 лет назад

avval

@Arek_R. 6 лет назад

Duh, 40 min vid about repairing SMPS...

@plemli 7 лет назад

Well-meaned thanks anyway, but the repair of a basic swps isn't that interesting. Spending more time on the instrument itself would have been far more rewarding for your viewers.