What Killed this $99 Servo? A Postmortem

[@dom1310df]

If the new servo has the same PCB inside you might be able to exploit the ST-Link firmware-dump bug to extract the firmware from the new servo and flash it to a fresh microcontroller for the old servo. That's assuming the microcontroller's read protection is actually enabled; if not it's even easier to dump the firmware.

Had the same idea... I definitely would try it.

[@sumduma55]

I was curious if something like this was even possible considering he had a "copy" in the new version. Thanks

[@pitot1988]

How can one typically extract firmware from an existing STM32? What kind of interface or dongle is needed to connect the the chip's pins to the computer?

[@ChristopherGoggans]

​@@pitot1988 I haven't specifically looked into this board but one thing I'd suggest researching is search for UART. It seems to be a serial connection and programming standard interface. The other you could try was searching for JTAG.

[@Teklectic]

​@@pitot1988 you could likely do it right through the programming header on the board, if there's no protection enabled, dumping the ROM is pretty straightforward, I'm sure someone has a video about the process here somewhere.

[@stumcconnel]

Do you have a lot of electronics background? As an EE of many years, I think you did a great job of explaining that whole process and identifying the operation of the various circuitry. Awesome job! And I think you made the right move buying the same motor again, at that price point it would be silly to re-engineer it.

[@howardrobinson2680]

I agree with Stu completely and in both respects.

[@Patrik6920]

...and another point is spare part if somethin else fails in it... unless its the same chip ofc.

[@dieSpinnt]

"buy cheap, buy twice" ... in this case let's wait for part three ... Jokes beside, nobody can tell if the expensive branded option would also have failed. Because of the circumstances that lead to this failure ... like over-voltage, shocks or the usual "produced on a Monday-product" ( hehe ). But all this is speculation and only one kind of person can exactly know what is the right thing to do: KZbin commentators ... :P But what you CAN say is that the brand-manufacturer provides guarantees. F.E. exchange in-between 2 or 5 years, or lifetime; Customer support and possibly help with the design of your contraption if some hurdles occur. You just have to RTFM!:) I don't see any reason to hold court about Clough42's decision to go for the cheaper exchange part. One way may be as good as the other. But one thing he said in the video made me think: that it is practical now, that he can just exchange the motor and has nothing new to adjust. Branded and certified products (this is why we in the industry use them ... and also to not land behind bars ... **g** ) guarantee a time-span when they are produced and can be supplied[1]. This is also guaranteed for spare parts and software for such systems, which are often modular and extensible. My opinion to the question if that was a good choice: It depends ... and you do you!:) [1] Edit and Example: For example and out of the field, the not so cheap motor and motor driver parts including all connection systems and cabinet parts from Siemens come with extensive personal advice and guarantees on availability and service. Some parts will be in stock for 20 years, some are even guaranteed to be in stock and with maintenance support for 50 years. You will certainly look in vain for this at the "Alibaba" dealer.

[@VoteForBukele]

Mtbf is 2 years. I can tell you from experience that the clear path would have lasted significantly longer as long as it was sized and installed correctly. Just my opinion, but decisions like that add up, and you can find yourself “going broke saving money” quickly. I watch people do it every stinking day.

[@Patrik6920]

@@VoteForBukele normally i would agree...but its obvious he does know a bit in electronics and is likely to solve many possible cenarios... guys like this are very valuble for any company...

[@javaduke1]

I think you did the right thing, hopefully this servo will work just fine. I'm saying it because I recently finished building your ELS for my lathe and I used the same servo. Hope you are reading this comment, I cannot thank you enough for your brilliant design and fantastic videos that guided me through the entire build process.

[@HangarQueen]

I watched this with keen interest (and was "rooting for you" through the diagnosis, hoping you'd find a simple fix) because I have the exact same servo driving your ELS on my MX-210V. Mine has been working perfectly well for about a year now; hoping for many more. Still, for $99, it's a terrific bargain -- unless these failures become a pattern. Thanks for the excellent walk through of the circuitry; very informative and entertaining.

[@YouveBeenCabadged]

There are usually some internal regulators inside the microcontroller, outputting internal core voltages onto lowish value ceramic bypass caps near the micro. Those multilayer ceramics are some of the most common things to fail - they can crack when the board flexes or vibrates. If one of those caps is shorted, I'd expect the regulator in the micro to get hot. You might be able to identify the culprit with a multimeter, or by just pulling the bypass caps off one by one.

[@lwilton]

That sounds like a reasonable possibility. A servo is certainly something that can have some vibration, especially mounted on a large vibrating machine. I don't know how much the boards would flex, they looked reasonably well mounted. But it is certainly a possibility. The interesting question is whether the microcontroller would have survived after the internal heating.

[@jeremylastname873]

An ohmmeter with Kelvin connections might get you into the ballpark.

[@Teklectic]

The hard part with those ceramics is that if they're broken, it's basically impossible to know the value without the schematic.

[@kurtbilinski1723]

@@Teklectic Could remove two, the bad one and a good one, then measure the good one with a capacitance meter.

[@philgarbarini9645]

Thanks for taking the time to share this. Are you considering a Clough42 redesign of the board that failed?

[@AmateurRedneckWorkshop]

A gremlin let the magic smoke out of that servo. I can honestly say that I have done the same, bought the same thing that betrayed me and sometimes it betrayed me again. Thanks for the video keep on keeping on.

[@BobGarrett66]

James I’d say it was a good idea to go with an even exchange. Now with that said, if this one craps out in a year or two, it might be worth stepping up (pun intended! 😂) to a more reliable long term solution. Thanks for the video. They are always a pleasure to watch.

[@glennedward2201]

These servos are typically great but i would’ve thought a 300w model would’ve been more appropriate for his application.

[@STRIKEcorperation]

It's rated voltage is 36 V. You can see at 2:36 that you're operating the device outside of it's rated operating range. This is most probably why the device failed. An avalanche breakdown of the buck regulator would lead to avalanche breakdown on the linear regulator which would expose the STM32 to the full supply voltage, causing internal breakdown and latchup. This would explain why the microcontroller is drawing high currents at roughly two diode drops. You should get a different power supply if you want to avoid this $99 mistake from repeating.

[@gregrice1354]

You just popped up in my KZbin feed. Great work. Great subject mastery. Great video documentation. Great honest, human communication! (Thanks for the Dentistry Lenses tip for "old man glasses!) Masterful - novices or skilled pros can't help but learn from this video, sir! Great common problem of "buy replacement" or go through work of warranty, repair, research new source/parts - across all walks of life and lines of work. Of course your time and expertise are so obviously valuable, that the time saved in re-buying is wisest choice. Wow.! Thanks again!

[@smkole2]

James. Thank you for this walk-through. Your explanations may be the only ones I can watch start to finish and truly understand the information. Have a great week sir.

[@buildmotion1426]

Genius! Thank you for posting this video. I’m configuring these servos with a masso. Got the db9-usb cable from A..zon and finally have a connection. I’ll try 500 steps too as a starting point. I greatly appreciate your channel and hopefully your getting rewarded for your hard work!

[@davekellogg6819]

Hi James - I’m very interested in knowing more about the dental glasses. Source? Cost? Would you recommend them? Pros? Cons? Optical clarity? FWIW, please do a video on the glasses. There are a bunch of us old guys out here, and not much info in YT machinist land for vision aids. OptoVisors work only up to a point.

[@SianaGearz]

I'm not old, i'm only 40, but i need all the vision help i can get as well!

[@mattw7949]

+1. Looked for this comment to see if there was anyone else who is also old and blind. I tried one cheap rando dental loupe from Amazon and it was useless rubbish. I know some must be better than others, but I aborted my search.

[@SRG216]

I'd like to see a link for the dental loop glasses too.

[@voodoochild1954]

I’m also interested in these. Can you provide a link for them?

[@DavidV328]

+1. I d like to know about them , too. Real dental magnifiers are screamingly expesive though. I m hoping this has a more reasonable price tag.

[@daveeymundson6800]

Hi James, I thought it was a good idea to replace the servo with the same type as you will have an opportunity to extract the firmware from STM32 on the new servo. Could be the making of another great video for the future. Never a bad idea to replace a part with a known good one. I know lots of mechanics that do that very thing each and every day. Thanks again for all your efforts in producing great videos.

[@mattmurphy7030]

Great job putting all your tools in the description. That's hard work and dedication to a good video 👌

[@bobuk5722]

Hi James, useful walk through to show how to diagnose the problem. Thank you for spending your hard earned money to let us know if it is a generic fault! I've still got your wonderful ELS on a breadboard ...... one day, one day.

[@72MQuinn]

I decided on mine to go with a 36 volt power supply because the technical book that came with the servo says to leave room for back feed EMF during deceleration. I wonder if your pushing it past what its little buck convertor can handle over time. Just thinking out loud.

[@kermitfrog1897]

You might be onto something...wonder what voltage the buck converter is supplying to VCC at the micro when you add reverse EMF to the 42 volts on his input? There is a 3 terminal regulator before the micro, but the manual does specifically mention leaving headroom for back EMF

[@cheyannei5983]

I was thinking that! I didn't see a whole lot of input protection on the buck converter, they step down the voltage but they don't isolate anything

[@PNWPrototyping]

I had that same thought. The motor may be rated for 48V but that drive circuitry is rated for much less. It looks like they depended on the body diode on the FETs to prevent back EMF instead of a robust design that uses an external diode.

[@Robo12555]

​@@PNWPrototyping Buck converter (LM5007MM) is rated up to 75v. Back-efm from the deceleration will simply charge the cap on the 42V rail to higher voltage, no matter what diode will be used. Body diode is enough in bldc motor drivers, you can reuse mosfets shown on the pcb as a ideal diodes.

[@Robo12555]

​@@kermitfrog1897 Voltage after buck converter don't change. Should be approx 8v

[@MrSneakyGunz]

Damn Son! You really do have all the toys. I think you're an underrated channel here on the KZbins, James. Keep up the fine work Mr.

[@larry527az3]

Spend hours reconfiguing a new servo or $99.00 for the same one that fits. I'd do the same thing too, your time is money too. Now if it fails again then all bets are off as to if I'd take the time to reconfigure... I'd say you chose wisely. Oh, you forgot one tool in your list of tools used, like you my eyesight isn't what it used to be and I'd like to try the magnifier you used. Thanks for another great video James!

[@orangetruckman]

I enjoyed your explanations of everything. The component identification was great. I’ve tried watching other videos on electronic components, but they don’t have the entertainment flare you’ve got. And I wouldn’t say it’s dumb to buy the exact component that failed the first time around. If it craps out in a similar fashion as the first- “Huston, we’ve got a problem.”

[@svrs]

thumbs up for knowing what you want, why you want it, and chasing after what you want., even in a failure, you're making it a win teaching us doubt it. thanks

[@grahameida7163]

You were correct to replace with the same, stm32 blowing seems a random failure, unless there is back emf appearing, very unlikely with what looks like optical isolators before the power electronics… would have been interesting just to break the power supply to the microcontroller and see if the psu and regulator recovered to 3.3v more out of interest then anything else.

[@jaro6985]

The opto is between the STM32 and the outside world. But the stm32 is not isolated from the drive circuitry or the motor.

[@DavidLuthy-ej9fe]

I built the ELS about 1 year ago and love it , no more gear changing , I was wondering if you had any plans to add any features to the firmware, such as automatic stop and start and return to the tap cycle Just a thought Thanks for the great projects looking forward to the future

[@Ghlargh]

I have used about a dozen of this exact servo, we did have one break but in our case it popped one pair of mosfets on the 3 phase motor output. I simply replaced those FETs (and the fuses which blew as the rail was shorted) and the servo has worked fine since.

[@greener121]

James, I love the diagnostics that I will never understand but understand enough to say that replacement of the component was perfect. no parts cannon here.

[@gravydog51]

I consider myself pretty good at a lot of things but I bow to you without any hesitation.

[@CTRLyurself]

If you go to the settings in the FLIR software, you can adjust and remove the paralax issue.

[@mtbmike]

great content man, love how diverse your machining videos are. I think you took the correct path, I personally do something similar with my projects. Keep up the good work.

[@bushmasterflash]

FYI, some Leadshine resellers or volume users can obtain new spare parts for the motors including the PCBs. I have replaced some of their encoder/hall sensors before now on their regular servos.

[@KallePihlajasaari]

This was the comment I was looking for. Contact Leadshine and send a link to your video. Tell them you will do a video of the repair when they sell you the spare PCB or Microcontroller.

[@teropiispala2576]

I also had a problem with one of my Chinese stepper motors. For me it was a mechanical and I was able to fix it. Not before I purchased new one, but it's always good idea to have a spare if they are used in important place. It's funny how they appeared to be relatively good quality but there is still some details which fail. Mine stopped spinning but coils were powered and there was some sound when I drove it, though controller went immediately into error state. I suspected short circuit, but all coil resistances were OK. When I opened it up, I didn't find anything wrong but when I put it back together I realized what the problem was. Face and backplate were machined in a way they didn't lock into place. Alignment was maintained only by friction and it was big nema34 motor. It had been slipped and prevented motor from spinning. I redesigned my mount so the motor body is supported by rubber, and it has worked well since that.

[@barryomahony4983]

So glad I stumbled upon this channel. Great stuff!

[@GeoffTV2]

I've no idea if you've made a good decision. What I do know is you did what I would have done. Hope it works out. Thanks for all the great content.

[@dirtybarry7002]

We recently had an X-axis servo motor fail on a Juki Pick and Place machine in our factory. I very quickly came to the conclusion that they were not intended to ever be taken apart so instead of digging further I put it back in the machine with the power disconnected and ordered a replacement motor. After the replacement arrived I forcefully disassembled the motor and found the cause of death was a split magnet on the rotor from years of rusting and expanding until there was nowhere left for it to expand. The moisture must have gotten into there during manufacturing as the motors are entirely sealed from the outside world.

[@einsotto9976]

I have 3 of "those" servos but made by jmc (IHSV57) The PCb looks nearly identical. only thing is that the LDO is on the bottom and the Buck is on Top. The Failure stayed the same. There seems to be some sort of problem with this kind of Servos.

[@kermitfrog1897]

Can you elaborate more on what you know about these failures? Sounds like you've had the same experience

[@lennywintfeld924]

If the new servo's microcontroller doesn't have an internal security fuse (or if it does and the fuse hasn't been burned) you could extract the firmware and possibly repair your dud. You just have to decide whether it's worth going down that rabbit hole for a $100 item. At those prices a one for one swap seems like a wise move. If you find yourself faced with having decide whether to buy a third one at some point, then go for a higher quality one. My $0.02.

[@paularbon1093]

I think you did the right thing. It could have been a one-off failure with the device. Time will tell. Thanks for your explanation during the fault finding.

[@cnng3506]

This is just awesome Sir. I've learn so much just by viewing this video. Thank you for sharing

[@LIKEABOSSTOKE]

You could read the flash to extract the binary file from the new motor's STM32and then replace the uC on the old motor, to then program the new uC.Will cost you a second servo anyway, but you'll have a replacement, at least.

[@azinfidel6461]

Yes, I was looking at that debug connector on the main board.

[@antontaylor4530]

Never hurts to have a backup.

[@Bashere]

Possibly... most likely scenario is that the flash read back lock bit is set. There are ways around this but takes time and energy.

[@ferrumignis]

Highly unlikely that the micro is unlocked for reads, but worth a try as the STlink is such an inexpensive programmer/debugger.

[@station240]

STM32C031C6T6 actually possible to buy one of these, ST Micro's parts have been out of stock for ages due to supply chain and stupid management issues.

[@ZomB1986]

I noticed the servo claims the input voltage range is 24-36V. Putting more into it can stress the buck converter. You'd think that's the only thing a too high input voltage can do, but buck converters can be weird. When it glitches or crashes, it can cause the input voltage to be put directly on the output. If this happens quickly enough, the high frequency voltage rise may be more than the LM1117 can handle, and *it* can briefly output the glitched voltage before it has time to adjust itself back.

[@Clough42]

Yeah, their specifications are a little inconsistent. Some manufacturers of this servo say 36V. StepperOnline, where I got this one, says "Input voltage 20-50VDC, output peak current 0-6A" in one place, and "Input Voltage: +20~50VDC (Typical 36VDC)" in another. The table in the manual says 20V minimum, 36V typical, 50V maximum.

[@kermitfrog1897]

@@Clough42 The manual has a clause about allowing for reverse EMF , spikes etc above the 36 volts. So I interpret that to mean that 36 volt is max for power supply and 50v is max for total sum of power supply + reverse EMF + spikes etc. This is on page 2 of the printed manual that comes in the box.

[@mosfet500]

Thanks James. One thing, you always discharge capacitors before connecting an LCR meter.

[@UncleKennysPlace]

I tested mine by powering it up and then going on a trip for a few days. Not intentionally. Still works. Quickly approaching 100K, James ...

[@Clough42]

Yeah, we're getting close. Couldn't do it without all of you!

[@merendell]

Interesting seeing you attempt to diagnose and fix that servo. I work in a motor repair shop and my specialty is servos but I would never get one of this type across my desk. Considering tech labor runs in the ballpark of 100-150 an hour it would never be cost effective to repair one that inexpensive and available. Generally if its under a grand and the shop manager lets it through the doors at all its give it a quick inspection to see if its something quick to fix and if not quote a replacement

[@thisnicklldo]

The part of this that really surprises me is that you were able to obtain the exact equivalent, 2 years down the road. I doubt you will be able to do that in another 2 years time. It's possible that the 'upgraded' model available then will be close enough in format and specs that you could fit it, if you are lucky. I think in your shoes I might buy another one now, whilst they are still available. I understand you would probably want a different model if this one fails again, but that's a lengthy project and will leave you without a lathe for a couple of weeks at least. With a spare, you could be up and running in 5 minutes, giving you time to implement a different servo/stepper installation. Not much more than the cost of a set of Starrett screwdrivers.

[@phildegruy9295]

Good job on the explanation of the circuitry. I have run into this in the past with servos/steppers and various other electronic equipment in industrial automation situations. The stepper is printed with a very clear 24-36Vdc min-max power input range. You mention the instructions say something about 48v input an are feeding it with 43 volts from a 48 volt supply. That would be incorrect. You should always stay within the range printed on the servo for power input. The new servo will work awhile and quit again as the 43 volts you are feeding it with is more than +10% of the 36 volt max.A lot of stuff, especially cheap stuff can't really tolerate any voltage more than a volt above the max printed. Put it on a 24 volt supply and turn the supply up to 26 if you want and the stepper should be much happier.

[@kermitfrog1897]

@Phil Degruy You are correct. I have one of these motors and the manual states: "24-36 volt recommended. Please leave reasonable reservation for voltage fluctuation and back-EMF deceleration." I'm guessing the 48v is the max when you add power fluctuation and back-EMF to the supply voltage. The question is, Would the compromise in performance using a 24v vs 36v supply be enough to prevent the motor in the ELS application from keeping up? My lathe is similar to James, and my design uses pulleys and the lathe gearbox to gear the leadscrew down while maximizing motor speed for more torque. I wonder if this setup would keep up at 24 (or 26)volts ?

[@phildegruy9295]

@@kermitfrog1897 I'm not well versed in the engineering design for steppers, I usually just fix the broken systems and turn the voltage back down to within ratings or recommend installing a larger stepper/servo if it is proven to be under powered in production. Can't really tell you for sure in yur case, but I'm thinking if your torque requirements are somewhere in the middle of the steppers torque range it would be fine. Torque is generated proportionally to the winding current. Stepper motor driver supply voltage does have an impact on how much torque the motor can output. As a stepper motors rpm increases, the available torque output decreases. The stepper motor datasheet will sometimes have a rpm vs torque curve graph. Usually it will have a torque curve for a motor supply voltage between 24 and 48 volts. The higher voltage will have a better torque curve. However the nameplate rating of the stepper motor with the all in one integrated drive electronics should not be exceeded by more than 10 percent and ideally kept within the range on the nameplate. You can turn up most 24 volt supplies to about 28 volts and still be under. I just know from experience that 26 is usually the sweet spot on a lot of things I worked on. In James's case I think the buck converter needs some time to saturate the coil and begin working properly which in turn feeds an excess voltage to the 3.3v regulator that has a max of 12 volt input if just for a fraction of a second.

[@stephenjohnson6841]

Great content as always! Thanks again James!

[@stephencase5160]

That was an interesting postmortem, and well explained. I liked the idea of using the thermal camera.

[@kurtbilinski1723]

I LOL'd at you shaking your finger at the lathe door :). Based upon your Clearpath review and my own research, I bit the bullet and bought them for my future CNC router. What decided it for me wasn't so much the hardware, but the apps. The thought of buying something needing sw configuration from China just seemed ripe for disappointment.

[@MrEmbedded]

Put a 3.6 zener on 3.3v rail and it might save this servo. Often over voltage on VCC kills processor. For example turning motor by hand making generator might do it.

[@protonx80]

i think it is designed for that purpose ... ergo it will have its own protection

[@feedback-loop]

That Rigol supply has two 30V channels, and they must be floating. So you can connect them in series to get up to 60V. Say, connect negative of the first channel to positive of the second channel, connect your load across both (positive from the first and negative from the second), enable tracking, and set the voltage to half of what you want (20V to get 40V).

[@zaidhussain5206]

Thank you for sharing this video, you did the right choice to save time & effort, wish you good luck.

[@TomDetka]

The only issue I see here is you didn't say you bought 2. Put one in and keep one as a backup. For low cost mission critical parts like this I always try to keep at least 1 extra on hand so I can get back up and running ASAP then order the next spare with a little bit less pressure to have it right now.

[@daneliberatore4583]

Two is one and one is none.

[@neonone9164]

Love ur diagnosis method, very methodical, logical and we'll thought out

[@electro9480]

Always pros and cons, you made the correct choice. Great video.

[@mcc5651]

Nice troubleshooting, satisfying to see a pro at work

[@jasonestes8954]

I too have this same servo and all the components to build an ELS, I simply have not had the time to put it all together yet. I hope this new motor lasts longer than a couple years as well. Have you considered adding stops to the ELS to make threading to a shoulder easier?

[@joewhitney4097]

I think you made the right decision. Now, if it fails again in a short amount a time outside the warranty, time to change.

[@millardalexander8270]

When dealing with electronically populated PCBs by using a pencil around the circuit (CCt) you can place carbon particles on the PCB which can cause short CCts in the most extreme case

[@peterbontinck1947]

On deceleration back emf of the motor can cause an overvoltage, that's why they advise 36v so the power supply output capacitors have some headroom to stop it. When using tighter margins, a good practice is to add some extra capacitance or use a crowbar circuit to shut on overvoltage.

[@peterbontinck1947]

A crowbar can be as simple as a power Darlington NPN with a 1k resistor between base and ground and a 47v zener between base and +43v.

[@jedfrank9597]

Love watching your videos, you do a great job of putting them together and are very informative. This might be an expensive request but is there any chance you could do a video comparing servo motors (not steppers). Personally I've used Clearpath motors in 2 CNC builds but I've since heard Delta servos are cheaper and better and then maybe Fuji servos?

[@stephensaines7100]

It was sound logic to replace with same. If this one fails, then logic indicates change of model. At $99, it's a no-brainer really. You get an astounding amount of engineering for that price, and you also have some spare parts to service the replacement, unless the same problem happens again, in which case pretty much proves a week point in the design, or your operating parameters are too demanding. Your operating voltage is a tad high as per specs, it could have been a spike that punched through. Slap your scope on the power feed to see if there's any undue amount of noise on the line. If so, try a line filter. Good vlog! I'm subscribed.

[@MikeMcAuliffe-g2f]

Given time and money, you did the right thing. For efficiency, you should have spares, anyway, right? I missed the stat about how much time you got off the failed motor.

[@MrKeithCraig]

Stops video at 6:57 and goes to Amazon to find dental magnifiers.

[@JulianMakes]

Me too! I need details!

[@arthurdent8091]

Hi, great vid. Would you please be so kind as to publish the urll for those magnifying specs. Thanks

[@jan_mohorko]

Have a look at AC Servos. Bought 1kw for 175€ some years ago. There are some smaller ones with 400W too. Step/Dir control possible, but can be used in torque and velocity mode too. No external power supply needed. Trust me, AC is the next step on your killer ladder...

[@clive4500]

I have bought one of these electronically screws from you and it is absolutely fantastic. I built it into my mini lathe. I printed a plastic 3-D enclosure for the main circuit board and put that in the enclosure where the changed gears used to be and the belts are still located. I have also bought one of these built-in stepper motor and driver seems to be okay at the moment. Initially I had some problem with interference. But the development board was not earthed to the main chassis of the lathe. Switched mode power supply and I suspect coupling capacitors caused the potential of this board to fluctuate. As there are Opto couplers everywhere. As soon as I earthed the board to the lathe all problems went away..

[@_Everyone__]

Well done, very sound knowledge of electronics as well, kudos!

[@darrellsharrock3859]

The design of the power circuit for the processer was fine and the caps were good so I think you just had a unfortunate processor failure. If it happens twice of course, time to upgrade, as logic dictates. You don't need captain obvious then 😊. I'm new to your Chanel and I must say, what a elegant solution you created. Having rotation speed feedback, nicely done. I am an admirer.

[@rotaone8513]

Hi James, i would have done the same as you and bought the cheaper servo. You were just unlucky as STM micro processors are used in cheap as well as expensive equipment and could have failed in either. The other point i have is the cost versus benefit of only $1.00 per week based on $100 for 2 years use, i think that is a win in my book. Cheers

[@oliverer3]

I mean there are definitely poor design choices that can be made to increase the likelihood of killing a microcontroller, but otherwise, I agree that as long as it isn't a recurring fault it's worth getting the same motor.

[@shawn4983]

Have you got a link for those dental glasses if they work well?

[@DrFiero]

Getting the same servo isn't lazy... it's strategy! :D

[@jimix321]

Now you should backup the stm32 memory so you can repair the old one for cheap and use it as a remplacement or for any other tool.

[@Clough42]

That might be worth playing around with. I suspect the firmware is locked, though.

[@retromodernart4426]

@@Clough42 You never know, it's worth checking to see if you can get the firmware and flash it onto a new MCU.

[@ricande]

@@retromodernart4426 The stm32 has tamper-detection erase, if enabled.

[@jimix321]

@@Clough42 That would be a shame. Maybe It isn't as seems to be sold under different brands. I hate throwing away perfectly good hardware for small defects like that.

[@tenlittleindians]

@@ricande Where did you read that? The stm 32 and the boards they live on are currently growing hotter than the Arduino boards. The blue pill and black pill boards all use similar chips and can be bought for a couple of bucks. There's many copy chips too but most people are not reporting any major difference with the copies. I like the pill boards because I can program them with the Arduino programmer. I even tried ChatGPT to write code for the stm 32 chip and it spit out code faster than I could type!

[@campbellmorrison8540]

So how do you find those glasses, I have been looking at the same thing that is popping up on my FB all the time. Im in New Zealand so by the time I get it here its not as cheap as I suspect it would be in the US so Im a little hesitant having been bitten by some previous adjustable glass's I purchased that were useless. I do like the look of these and I assume I can fit them onto my prescription glass's and they dont fall off etc. Any suggestions/recomendations

[@donaldelrod9172]

good job and great explanation of what's going on.

[@william5694]

With a little legwork you could probably source a replacement board; giving you a spare servo for the shelf.

[@injoelsgarage3934]

James you did the right thing nicely done!

[@billh308]

Since when do ST's go bad? I'd say it was a safe bet to buy the same. I'm glad you took out the thermal camera, you watch Northridge Fix too?

[@AllenCavedo]

Nice video and problem solve. I’d like to know why you put that lead screw servo on the lathe? The lathe already had a lead screw gear system. What does the servo provide? More ratios?

[@mytuberforyou]

Your teardown was great- however the unprotected pins and lack of water/oil/swarf resistance wouild make me go for the Clearpath, hands down. I can't believe that wasn't full of chips and muck, there are no spots behind my lathe that don't get covered with oil droplets and metal dust.

[@TheUncleRuckus]

I don't blame you for getting the same servo one bit. Screwing around and having to reconfigure your setup to swap in a different motor is a huge pain in the arse, you might as well keep it simple. Hopefully this one will last longer for you! 🤞 If not then I would consider switching servos so you're not having to spend money every year or so for a new one. 👍👍

[@wizrom3046]

I'm not sure if you are aware, but these Nema style motors heatsink into the aluminium mounting bracket. Using a plastic mounting bracket has almost certainly caused the motor to run hot. Excess heat is also a common cause of microcontroller failure. I'm not saying that is definitely the cause this time, but a proper aluminium mounting bracket will greatly reduce vibration, heat, and is just a great deal more professional way to do this. I would probably have run the same type of cheap motor again, but would never have used a plastic mounting bracket on a Nema style motor...

[@StevenCookFX]

I have the clearpath servos. They are working excellent. you do not need a converter cable and the diagnostic software has built in ability to not only monitor but tweak performance. It is so good that one of their techs who remotely was helping me discovered that I had the wrong coupler. The coupler I had on my Z axis was a spring type you typically use for a 3d printer. I changed it out for the correct one per their recommendation and it cured the issue I was having. $99 servo is ok for some things however I would gladly pay 300 for something that has great support and is local so if it breaks down I can get it replaced easily and quickly.

[@DarronBlack]

Clearpath is great for single motor applications... or mechanically isolated axes. I was disappointed twice over when we tried to use Clearpaths for my son's 3D printer build. First, no support for gantry configurations with two motors on one axis. You have to disconnect one mechanically and tune with one side only, save that tune to the other motor as well, and hope the mechanical system isn't too different when both are connected together (and it definitely is quite different). Crappy. Second, our original design was a H-belt configuration where two motors sat on the edge of the machine and drove X&Y without any heavy motors on anything moving. That was a disaster as even a 3 hour support call with Clearpath trying to tune it we could never get that to work. The motors, being mechanically coupled in that configuration, just fought constantly. So, my "let's use servos" was a huge mistake. Eventually, we got the gantry config more or less working... but it still has wavy effects in the print with occasional mild oscillations due to not being able to do a proper tune.

[@michaellinahan7740]

James not wishing to question your choice of motor ... but other ELS builders have quoted using the 3Nm version of the Nema23. Have you ever experienced issues with insufficient power when turning/thread cuttting tougher materials?

[@vincehogg8935]

Hope he new one lasts. I have just installed the same. Cant remember why you changed steps to 500? I just threw mine in after setting the switches. By the way, just found a new use for the ELS. Will use it to wind solenoid coils neatly. Will print a spool holder/wire tensioner to go in the toolpost, stop and reverse at the ends.

[@donepearce]

Good choice, but maybe you should have bought two so you have a ready spare. And in refitting, I would definitely have turned that printed bracket over so it can pull back straight again. As for fault finding with a thermal imager, that was a game-changer when it became available. If you have time, save the thermal image of a good working unit for comparison when there is a failure.

[@gregfeneis609]

James, please continue to review the construction of the motor control board. Perhaps the power or control circuits for the MCU are not isolated or protected enough and a transient voltage took out the MCU? Looking forward to seeing how long this 2nd motor lasts. How many of the cheap motors do you have to buy in order to break even on a spendy motor?

[@gregfeneis609]

Utility power transient through to the MCU, or a motor power circuit transient.

[@jeffjefferson2676]

I would check the input signal voltage under every circumstace just to be sure there are no voltage surges happening. Something must have destroyed the chip. Sometimes its bad board design, but its best to be sure its not your input that destroys the chip over time. Very interesting those thermal cameras, ive seen some good analysis done with these. Greetings, Jeff

[@OnHoldAt50]

A man after my own heart. Skip the schematic - this stuff is all the same, just dive in and a bit of logic, problem solved. You and me are the people everyone needs the day the SHTF. Great presentation sir. I was thoroughly entertained.

[@CraigVanSickleAK]

Appreciate this update!

[@DEtchells]

I enjoyed the diagnostic walkthrough, encourages me to do more digging on complex devices needing fixing :-)

[@Neudezign]

If it ain't broke don't try to fi... oh wait. I can't blame ya for replacing it with the same motor, I mean for only $100, I would have done the same thing. I really appreciate how you did a walk through of the electronics on the boards and showed how you troubleshoot the issue. The thermo-camera was a nice touch. Although, I'm a little disappointed you went through all the trouble and didn't take the time to sharpen your pencil. Come'on James! j/k 😂😋👍 I always appreciate your videos, definitely looking forward to the next one.

[@dripfreefpv9695]

Im still using my itty bitty dual flexi extruder on my makerfarm I3v. Im a big fan of your work.

[@ingmarm8858]

That's a strange fault James. I would have popped the 3v3 regulator off or isolated the output. Perhaps the under voltage is causing the stm32 heating - unlikely as they do work from 1.8 upwards but it would have been worth double checking. I've had stm32 fail in particular under voltage conditions. Could be caps around the 32 as well I suppose. Cheers.

[@snappers_antique_firearms]

Is it possible to cut rifling using the electronic lead screw? I collect and shoot antique firearms. Every now and then i have to put a barrel liner in a gun. Colts originally had Progressive rifling. so it would start off straight and then progressively add more and more twist. I would love to be able to replicate this rifling. How difficult do you think this would be using electronic lead screw?

[@Otakutaru]

It should be fine for a while for sure. The power delivery looks solid to me. A buck into a linear should be reliable, so the problem was internal to the uP as shown in the video. uPs sometimes come up bad depending on the source

[@kvechannel]

Maybe the uc faulty is caused by the bad psu circuitry? On the stm32 disco boards the contoller emits no heat at all

[@Otakutaru]

@@kvechannel Well, the fact that theres current through the uC, and thus heat, means that power supply is at least not dead. It could be outputting more voltage and that could kill the stm, so yeah, maybe psu

[@jeanpierrelabonte2868]

Glad you are the kind of guy I would like to be from electronics to mechanics! Thanks

[@Sapper21b10]

If it's not broken, don't fix it. If this one drops you can upgrade. With the way tech goes it'll probably be smaller and have more power by the time that one farts and let's the smoke out.

[@Shocker99]

Leadshine is Chinesium. But named brands are about $1000 per axis, for both the servo and servo drive. I've been lucky enough to have used them all. I've enquired with Leadshine during the shortage, but they lack features of name brands versions. Most important to me is STO, which i think is important to have for something like a powerful servo. In the hobbyist space, unless the project was critical then i would also purchase Leadshine. But i would put all of the safety features on the project to mitigate the not as safe as it should be (as i require) servo.

[@gabrielenitti3243]

great in depth look! It really hurts having to bin an entire servo just because of a 3$ IC. Even reselling for parts wouldnt be economically viable. We should require for stuff to be easily repairable. Manufacturers should provide firmware blobs at least, so one can just replace and flash a new IC without the whole thing go to waste.

[@leslierhorer1412]

Mine also failed after only 5 months. The difference is, mine did have the green LED lit, but the shaft was not locked and would not rotate. Fortunately, when I disassembled the motor mount, IO found a loose connection. It allowed enough current to pass to light the LED, but not enough to drive the spindle. Tightening the red power lead fixed the issue. Phew!

[@hanksmith3628]

Hi, would please list the 'old-man-glasses' source? They sound like what I need! Thanks.

[@MD_Builds]

Id dump the firmware from the working servo, and replace the micro on the dead one. Then reflash it with a stlink. I should also mentions stepperonline are really good. It might even be possible to get the firmware bin from them if you ask really nicely.