No.088 - Rigol DG1022Z Arbitary Waveform Function Generator Repair

[@TheGmr140]

Love that signal generator 😊😊

[@HitAndMissLab]

You are real Sherlock Holmes of electronics! I've learnt so much from this one video.

[@alpcns]

Brilliant diagnosis and repair, and a fine instrument for the workshop! Thanks for the video!

[@GadgetUK164]

Fantastic repair and a wonderful donation by TDV Electronics!

[@oriole8789]

A thermal camera has been my primary go-to tool for these types of problems. Your video perfectly demonstrates that utility. It's also the first tool I use when it comes to verifying new designs, just for quickly identifying unexpected asymmetries, unexpected currents through parts or even traces, power supply issues etc. In my case, I'm using a slightly higher-res camera (640x480 Flir Boson) that's running on my own windows software (utilizing Flir's API) with various features to simplify realtime analysis. The focus is adjustable, which lets you get a sharp, hi-res image extremely close to the parts. It's a non-radiometric camera that I bought for a lower price, which I've converted to radiometric by creating a little calibration system in Python that gets it within less than a degree of real temperatures by generating various interpolated temp curves and interpolating them together into a 2D cal matrix which my video software then applies. It sounds a bit more complicated than it is, but it works. :] I personally view thermal cameras as indispensable troubleshooting and engineering tools, particularly because of how complex modern circuit boards tend to be. Great repair as always! Thank you for posting.

[@BTom16]

It's astonishing what can be done without even a schematic when someone knows some theory and has a bit of experience. Brilliant repair. Thank you for sharing it.

[@billpowell5931]

Your steps to get to the solution are so perfect. A great talent to have. Thank you for sharing.

[@IanScottJohnston]

Thanks!

[@TheDefpom]

Nice score, and nice explanation of the circuit, I’m sure that will help someone else with fixing theirs!

[@IanScottJohnston]

Appeared out of the blue this one.......but always welcome!

[@ryanbates1158]

you just saved me $346. have the exact same fault (the output was shorted on a faulty board). grounding the testpad shows the same promising conclusion,. ordered the op amp ($10.99 on digikey). thank you for this video!!!!!!

[@IanScottJohnston]

Happy to help.....and well done!

[@ryanbates1158]

Update: Got the parts. did the repair (that thermal plane was tough) and unit is fixed!!!!! thanks again. these spare op-amps are now taped to the case for prosperity. digikey 296-THS3095DDARCT-ND

[@IanScottJohnston]

@@ryanbates1158 Excellent!

[@jimmy2drinks]

Cheers Ian, that was fun to play along with :)

[@colincampbell4505]

Awesome job. So, how did you figure out what opamp that was? That would have been a trap I would have fallen into.

[@IsrarAli-kc3pe]

Sir, great explaining about Function generator output.

[@fredflintstone1]

nice gift and a simple fix, the skill was in identifying it well done:-)

[@andymouse]

Squeak !!!!!!

[@simontay4851]

eeee

[@TheBreadboardca]

Another sucess, nice one, a good demonstration of your understanding of test equipment and their underlying construction and design. your having quite the sucess rate with those, keep up the excelent work, great viewing, cant wait for the next one.

[@TheEmbeddedHobbyist]

nice bit of kit for the cost of an opamp and a few hrs fault finding.

[@somewaresim]

Brilliant piece of diagnosis. Funny I was just wondering this morning when the next video would be!

[@billpowell5931]

Very nice diagnosis and explanation. Thank you for sharing.

[@YanickT]

I'm fixing mine. The counter is defective. I found the input resistor 26.1 ohm was open. That's said, yes, you are correct. I can see 3095 on my op-amp. It's not erased on my device. v1.04 2018 Thanks for the video!

[@and1424]

this channel is so great. thanks

[@IanScottJohnston]

Thanks!

[@bradclancy6069]

Thanks for sharing. Excellent diagnosing and repair!

[@andymouse]

Nicely deduced !...cheers.

[@hightttech]

Very Nice troubleshooting. And i love solder paste; all that avoid it are missing out on magic.

[@hwj1822]

Learned a LOT from you. Thank you 👍👍👍

[@DavesAstrophotography]

Awesome job Ian, an 11 quid repair for a 300quid instrument!

[@ToltecMerc]

Nicely done sir! A great explanation of the output circuit of the generator.

[@OrbiterElectronics]

Great diagnosis and explanations too Ian 👍👍 Cheers John

[@cthoadmin7458]

What's design best practice here? Should the inputs have some protection from over voltage? Particularly transients? What would you expect to see on the outputs of a piece of Rhode and Schwartz equipment?

[@MrDomyboy]

Nice one Ian. We need to find a faulty device that gives you more of a challenge :)

[@c4t4l4n4]

He's got one... the Keithley, a work in progress 😃

[@IanScottJohnston]

Keithlet 2001 DMM.......If I can fix it then I'll be celebrating BIG time!

[@MrDomyboy]

@@IanScottJohnston I hadn't quite caught up in all your videos. Excellent. This Keithley looks like a tricky one 👍👌

[@stevensexton5801]

How did you determine what the OP amp was?

[@IanScottJohnston]

The Rigol DG1021 and also the Siglent SDG2122X use the same op-amp......so I guessed per the pinout and functions this one used it as well.

[@mal6232]

Experience!

[@pnjunction5689]

@@IanScottJohnston Good thinking! I was wondering as well how you came to the conclusion. I think otherwise there are quite a few opamps in that kind of package to go through.

[@irgski]

Curious - what FLIR thermal imaging camera do you use? Any recommendations for that one or another for general troubleshooting?

[@amirb715]

Hi-Z mode in ALL function gens from ALL brands is just a recalculation of the amplitude on the screen.. THe output impedance is ALWAYS 50 and never changes. I thought you should know that! Relays are there to (1) turn output on/off (2) bring in an attenuator pad or an amplifier in/out of signal path depending on amplitude range.

[@Chris_Grossman]

In the 1970s I worked with some pulse generators that allowed you turn off the "back termination" 50 Ohm source resistor by shorting it. However a 50 Ohm back termination resistor is always there for every other generator I have used.

[@thomasstran]

Correct. The output impedance is always 50Ω. Why would anyone think it could be changed to 100kΩ, 1MΩ or any high impedance is beyond me. How would that be useful?

[@nixxonnor]

Nice fix. Did the Keysight scope ever display the selected time base or voltage setting (x and y settings)?

[@bigmedge]

Hi Scott , a quick question about a part of your diagnostic process : from what I've researched , an op-amp's max acceptable differential input voltage range is +/- 700 mV . But when you tested the inputs @ 11:40 , your results were 0.7V & 1.3V - a difference that's of course still within that spec . Did you make the determination that the differential is too large based on past experience , or some other way ?

[@IanScottJohnston]

You are quoting the limit before damage to the op-amp occurs, however, in normal operation of a simple op-amp amplifier the two inputs should be virtually the same voltage. Since they were not the same it was obvious that the op-amp was damaged and the output was not able to work via it's feedback mechanism to balance the two inputs.

[@bigmedge]

@@IanScottJohnston Got it . Thanks for the prompt reply !!

[@TonyLing]

Excellent job. I've never heard of Kynar wire before. Is it just enamelled copper wire?

[@IanScottJohnston]

It's silver-plated copper solid conductor with kynar insulation. It was originally used for wire wrapping back in the day, but also known as hook-up wire and used for prototyping boards on vero board etc. I use the 30AWG size. RS, Farnell etc sell it, just search for Kynar.

[@allthegearnoidea6752]

Oh I was already excited for the Kiethley repair video. Great to see the Rigol. I have mixed feelings about Rigol. I like the scopes and the spectrum analyser but their DC load is a heap of junk in my opinion.

[@IanScottJohnston]

The Arb. Funct. Gen. is ok, but heck there's a lot of options all over the place not to mention display modes. Some options are buried in UTILITY not exactly sure why!

[@jaapweel1]

how did you figure out what kind of opamp it was?

[@IanScottJohnston]

If I remember it is because there is two channels.

[@henrythompson7595]

So, that opamp chip was used on both channels? If so, how come chan 2 still worked?

[@kevy1yt]

Very nice. How did you know which op amp was used?

[@IanScottJohnston]

The Rigol DG1021 and also the Siglent SDG2122X use the same op-amp......so I guessed per the pinout and functions this one used it as well.

[@shadimurwi7170]

Nice skill

[@qzorn4440]

hold on this is so interesting, i am going for coffee... i will be right back ☕🥧 thanks... 🙂

[@absurdengineering]

Maybe it’d be overkill, but I have some dislike for instruments that could be made a bit more robust and yet are not. You can’t make a spectrum analyzer front-end survive 20-some volts of either polarity connected to the output. But this thing? It could survive +/-100V on the output indefinitely without much trouble. Other than troubling the design engineer once, that is :) Maybe an ARB can get a pass. But power supplies that can be killed by a couple dozen volts AC dumped into the output - that really gets me.

[@byronwatkins2565]

I would have checked for spikes that could have killed the opamp, but it could have come from the output BNC.

[@IsrarAli-kc3pe]

Hi dear sir, I am Israr Ali from Hyderabad Sindh Pakistan. I am technician of audio amplifier, I was bought Rigol DG2041A few years ago and I was testing speaker during the test suddenly DG2041A giving DC voltage on output terminal on square wave function,then i was fully try to find this fault but still not successful. During repair this device i was open from PCB T5W 4pin (SOT 142) part and now misplaced it. So if possible kindly help me about this smd code and datasheet. as I can buy equalent number. Thanks and regards Israr Ali

[@jonka1]

You couldn't ask for better. A simple fault in the output and a working channel to compare it to. A nice bit of luck.

[@y_x2]

Lot of investigation for an obvious faultly component.

[@fredflintstone1]

Cheese strings!!!!!!!!!!!

[@JohnDoe-es5xh]

They accidently put 20V to the outputs. LOL! What experts working in that TDV electronic module repair shop??? Idiots wanted, huh?

[@arbiter1er]

Sometimes bruh moments happen

[@JohnDoe-es5xh]

@@arbiter1er must have been low IQed stuff. Not the best choice of employees.