CuriousMarc - 2024-08-20
My expensive lathe digital readout just failed, and Newall does not want to repair it! So, we reverse engineer it, and find out that the proprietary principle of operation is absolutely genius, involving ball bearings and magnetics, with a readout precision of better than 10 microns. And the fault is quite unexpected. Hint: not a capacitor. Update: Master Ken decapped the ferro-electric memory chip and made a blog about it, showing pictures of the unusual chip and explaining how it works. See it here: http://www.righto.com/2024/09/ramtron-ferroelectric-fram-die.html Stuff that supports the channel: - Support us on Patreon: https://www.patreon.com/curiousmarc - Amazon links for the tools I use in the lab: https://www.curiousmarc.com/amazon-links - Channel merch on Fourthwall: https://curiousmarc-shop.fourthwall.com - Legacy channel merch on Teespring (I don't have everything transferred to Fourthwall yet): https://teespring.com/stores/curiousmarcs-store "Elevator Music" Credit: Crinoline Dreams by Kevin MacLeod Our lovely sponsors - PCBWay: fast turn PCBs, https://www.pcbway.com - Electro-Rent: https://www.electrorent.com - Keysight: test instruments: https://www.keysight.com - Samtec: connectors: https://www.samtec.com - R&D Microwaves: https://rdmicrowaves.com Get more technical info on the companion site: https://www.curiousmarc.com Contact info: https://www.youtube.com/curiousmarc/about
That first version of the reverse engineered schematic is worth a print on a t-shirt 👍
I'd buy that.
I would buy that.
take my money
You went down the rabbit hole and came out with the rabbit and hat , well done. this should help other owners too.
Beautiful clean Sensor Signal, well deserved patent as it is even mechanical pretty accurate and still simple to process
Hello Marc! I'm the national sales manager for Emco (and I'm an avid follower of your channel) if you will ever need spares for your lathe, just let me know!
@@federicos8504 Woohoo! I love that lathe. Thanks for posting here!
The way that quadrature signal is derived from the ball bearings is amazing! Operating at 1kHz you should be able to diagnose if the signal input is working by putting a stethoscope on the transducer and listening for the 1kHz tone!
Tracking down, reading and understanding a patent, to end up replacing a memory chip ;-)
Fascinating video!! Thank you.
Good on you for using that clue, of losing configuration. That sure was a rabbit hole.
I think I got lucky twice on that repair…
@@CuriousMarc You sure did, the epic HP repair from a few years ago was caused by a similar short and it took months.
Would be interesting to read back the old chip and see if it's whole chip or just a stuck bit failure. Regardless, I would have assumed they store a checksum of sorts to prevent bizarre failures like this. Apparently not. Great repair as usual!
I would also like to see this. I've repaired a number of C80 DROs and the most common problem was failed keypads where the units would no longer register button presses.
@curiousmarc if your keypad ever fails, I can send you a custom PCB replacement. It's a bit of work to get the old flexible one out but the replacement works very well.
Another issue I had with two units, similar to what is shown in this video, where one or more axis would show corrupted data, was caused by issues with one of the socketed ICs making bad contact. Usually you could apply pressure to the affected one or slightly bend the board and it would fix it. Re-socketing each IC and cleaning the pins would fix it long term, even though they showed no signs of corrosion. I'd inspect the solder joints on the digital board as well and reflow any that seemed even a little off but I don't think it was a solder joint problem.
@@ourplesoop
I have a C 80 that is losing its accuracy, I have reversed the heads and originally it was short by .020 in. but after reversing it it’s long by .005 in.
Do you think by re-setting ships this may help this problem?
@@lazman111 He said there is a screw compressing the ball bearings you can check. The FRAM chip won't affect the accuracy.
@@ourplesoop could you supply contact info for your repair shop? My shop has a C80 that has a failing keyboard and would love to talk.
I can't believe how good of an idea it was to use ball bearings - that's basically an off the shelf part you can get in a tolerance of +/-0.00005". So you don't need to do much precision work yourself; no printing tiny optical scales onto glass, etc.
That’s the idea, affordable stable precision that’s oblivious to dirt and oil. To cap it off they have a pressure adjusting screw at the end of the rod so the total length of the ball stack is exact. It’s factory adjusted of course.
Those scales are very similar in operation to the Sony Magna-Syn scales that we still use on the larger CNC machines. Sony always provided a "converter box" to convert the "magnetic" signals to conventional TTL square wave output or the newer 1 volt peak-to-peak sine wave to allow us to connect them to any industry standard controller. Merci pour le video Jean-Marc !!!
There is a replacement type of the FRAM FM24C64B, if the WP Pin (write protection) is not used, the replacement is 1:1 compatible. If WP is used, then there are some Changes! B Type memory is fully write protected, the old type is partialy write protected only 1800h to 1FFFh is protected. If this feature is used, then FW changes must be done, in this case not possible.
Thanks for the tip!
Nothing i enjoy more than watching along and pretending i understand what's going on 😆... One of the few content creators i don't skip through the adverts because you deserve every penny of ad revenue.
22:50 Thank you so much for measuring the size of the balls, I was trying to eyeball it earlier in the video and you saved me from having to go back and check
A great comeback from an easy-to-make mistake. Public service achieved! Thanks for including the probe slip story. It happens so easily and can be so devastating. It's one of the most frustrating things to break something during an attempt at fixing it. I'm glad you had a replacement chip and that the FPGA was OK.
So, they made a linear resolver. Given that the resolver was the 'go to' rotary position encoder of the 70s (when first Newell patent was filed) it sort of makes sense they were thinking along those lines. The execution is brilliant. Makes me wonder about the transducers reading the bearings. Perhaps they are just mono compact cassette heads or something similar purpose made.
What’s really clever is the adaptive re-use of the ball bearings, which by necessity all have to be manufactured to super-low tolerances, and any variance with one is going to be averaged out.
I was also contemplating the nature of the odd failure. Since it displayed 'Start' on the top DRO (probably from ROM) and gibberish on the lower (instead of versions #), I wonder if it was trying to read a delimited string from the FRAM and getting back garbage which just happened to never be the delimiter.
Marc! I feel your pain... I was repairing an audio mixer, and I plugged in a molex power supply plug off by one terminal, and shorted the +48 phantom power input to the +15 volt rail.
This of course blew up every single Op-Amp on the board for every channel, every bus, and every output!! That really hurt!
Even reading about this hurts...
A lot of "penalty" hours with that desk 😅
Ain’t that annoying when that happens. But it is our lot. We repairers are made to suffer from blowing up our own parts.
That is so cool! Thank you for explaining how this worked. You know, funny thing, but I did that same stupid thing on a board I was working on last week... I bridged +12V to the logic +5V and blew up the Arduino microcontroller up. I experienced the horror the moment you realized what happened... I'm glad you got lucky and didn't have more damage, or needed that PLA chip.
It’s part of the occupation hazards…
Two geniuses at play here, the person who designed this and you for being able to figure out how it worked.
I always wondered how those linear measurement tracks work. Thanks for that
You should go out a buy a book of Powerball tickets! You are one lucky fellow! Two bad chips, after sending 15 volts into the 5 volt rail!!!! Excellent repair as always, nicely done Marc!
This was a particularly satisfying repair. I enjoyed seeing it on a modern piece of equipment because it's easier to follow the test process on a circuit board than on something with a tangle of wires (although watching those get untangled is its own form of entertainment!)
Brilliant work, Marc, as usual. That method of precision linear measurement is so elegant in its simplicity. I would suspect that the ball bearings are dimensionally very high precision parts, being about as close to a consistent 10mm diameter. I bet linear position sensor assembly is pretty expensive by itself, even though it's a relatively simple assembly. I would have never guessed that they would have used a FRAM device, but perhaps they were thinking about long-life versus SRAM devices with a built-in battery, like those used for configuration memory on old Sun workstations and servers. When the battery goes flat, they won't boot. Replacing the device doesn't fix the problem, either. You have to go through manual processing of reloading the base configuration parameters using the built-in Forth interpreter. Fortunately, it was much less cumbersome to reset the config once the FRAM device was replaced. FRAM was a pretty neat technology, but as this case shows, it simply couldn't live up to the longevity of good old-fashioned magnetic core memory. The core memory in some of my old calculators from the mid-1960's are still working just as well today as when they were new. I always love watching your videos, and this one was especially fun to watch as you reasoned your way through figuring out how it worked. Kudos! Thank you for doing your videos. They are a great example of the true goodness that the Internet can offer.
As usual, I’m in awe of the combination of comprehension and execution…wow! 👍👍
A former employer was manufacturing an evaluation boards for their processor cores. The CPU was on a card. Sometimes it was a hardcore (rarely), sometimes a softcore in a big ass FPGA (most common) or two for the most complex designs. We're talking about the biggest FPGAs money could buy which were expensive so dual FPGA variants were rare. The evaluation board was mostly a glorified I/O board, flash, voltage converters, what not. So there was little motivation to upgrade or in fact do any modification to board. The core of the I/O was an Intel PIIX. Eventually Intel cancelled that product line. No problem, we had ample stock. Then eventually RoHS came to truly finish of the board. The PIIX was not available in a RoHS variant, our stock was running low. The board could probably have lived another five or ten years as a meaningful evaluation platform with good software support.
My friend's company had to redesign one of their remote sensor boards when RoHS came in because the solar/battery controller chip wasn't available as lead free. The irony is that the battery was a YUASA sealed lead-acid battery which had considerably more lead than that tiny chip ever would, but "them's the rulez".
@@TheOwlman RoHS still makes sense. People have learned to recycle or dispose of lead-acid batteries properly. Here in Germany there's a significant refund on car batteries, 20€ I think it is. But electronics may still end up getting tossed out with household or other waste. And only too many amateurs or small shops only doing occasional solder work don't have proper ventilation to protect workers from lead fumes.
@@ralfbaechle I cannot disagree, millions of chips with a tiny bit of lead is still a lot of lead, it is just the irony of several kilos of it no longer being able to be charged by a chip with milligrams that struck me. It more shines a light on the past poor performance of electronics recycling that makes me hope they have improved in the last 30 years. The rise of lithium technology concerns me - I seriously doubt that will be as efficiently recycled as lead-acid until such time as either shortages or legislation make it happen. In the UK at least, the number of problems with fires from disposable vapes in domestic rubbish in on the rise; in Lincolnshire we have had a fire at a refuse facility in the last few days and a bin lorry caught fire out in the road last year, both the result of vapes.
And still there is a very toxic organic lead compound added to the fuel for airplane piston engines. Exhaust gets spilled as aerosol over our heads. How delicious.
I am a bit unsure about ROHS. Devices using Lead-free solder seem to have a shorter lifespan.
Alkaline batteries without added mercury will unavoidably leak and kill the device around them beyond repair, leading to even more e-waste. Batteries can even leak before they are electrically exhausted. So it's hard to notice.
If I remember correctly, there was a short time in the 1980s when alkaline batteries had become affordable and not leaking before the ban of mercury. Mercury stops a chemical process that generates gas inside the battery. Gas pressure builds up and causes the leak of potassium hydroxide solution.
Again, thanks for showing your mistakes as well. We learn as much from these as from your (often incredible) successes.
Ouch! Did the exact same thing, ie, shorted across a multi volt reg and killed my STM32 Disc board. It only killed the USB com chip, but did make programming a pita.
Excellent repair. 👌 Machine shop equipment seems to be in a world of their own. Very clever design ideas. Thank you for a great step-by-step video.
I'm impress, the vernier thing with the phases reading is a very clever idea. And that type of memory i never know about it.
Great episode.
And I am even more astonished when I see that the people who comment know more about the topics presented than I do. I am truly in the right place.
Nicely done! I too was thinking a bad crapacitor, but I would have never guessed the fault would be in the FRAM.
Merci for the video! I am now a little more appreciative of my Fanuc controllers at work.
Yup, learned something (several things) fun about electronics again from Prof Marc.
Thanks for taking up this noble cause and succeeding ! ... and ... I appreciate the learning.
That circuit is a very eloquent and brilliant design. Great reverse engineering Marc!
Some embedded devices fall into a "crazy mode" if some internal test has failed, in this case, the non-volatile memory. The device was deliberately generating random numbers. I've seen this before with a thermostat that briefly got a bad voltage. The LCD segments started flashing randomly. In my case, simply resetting the device solved the problem. You took the long way around but we learned more about how it really works, so I guess that made it worthwhile.
I always wondered how they worked, such a simple but genius way of doing it! Fabulous and thank you.
As someone with little clue about electronics it is fascinating how you could reverse engineer it. Also how the Lathe uses ball bearings instead of a decoder is amazing. Thank you for the great video.
Great video! Very cool how the sensor works. Thanks!
Amazing technology. Very ingenious! Thanks
You are a genius! I very much like your attitude, your explanations and your superb videos. Pulled in by your AGC series once. Now a big fan. Well done. Again.
A VERY good find. Congratulations!
Thank you for clearing that mystery up for me!
Have been very curious about how those sensor works for a long time! Did my education on CNC-machines in the mid 90's storing the programs on paper tape!
those switched capacitor linear low pass filters are super cool! I've used an 8th order Butterworth lowpass filter in some A/D and D/A research projects! They are basically a brick wall filter at the cutoff frequency!
Thank you Marc, great trouble shooting video. This is an interesting tale. The decision one makes depends on the value of time. If the solution of replacing the chip were unknown, it would cost thousands of Dollars of an engineer’s time to find the fix, which luckily existed. Meanwhile if this were a production shop many thousands of Dollars of production would be lost while the equipment is down waiting for a fix. Replacing of the readout unit would be a bargain at only 1200 Dollars in the production shop case.
Now that it is known that the fix is an inexpensive though possibly difficult to source memory chip, the answer for people who follow Marc’s footsteps is to fix rather than to replace.
Much hinges on the availability of the obsolete memory chip. Those memory chips were $5 on eBay before this video went live; I’ll bet they suddenly got more expensive.
That was particularly interesting, thanks dude!
Yep that was cool. Funny how small innovations are built on over and over again. The good old Schmitt trigger comes up over and over again.;)
Absolutely fascinating! thankyou Marc
Fantastic video. My favourite so far!
So the overall accuracy is tied to the accuracy of a bearing diameter, and subsequent error that accumulates as they are stacked. Fascinating. I suppose a sphere may be easier to manufacture to a precise tolerance, possibly by tumbling (honing) in a media.
Thanks Marc for the amazingly interesting educating entertaining video !!!
So Ken is not the only wizard of reverse engineering! I assume most failures of this unit will be this chip... the weak point shows itself... way to go Marc.... I salute you.
I’m a baby reverse engineer compared to what Master Ken and TubeTime can do!
@@CuriousMarcNone of us were born knowing this stuff, gotta start somewhere!
@@CuriousMarc Do Patreons get the diagram? That would be nice. Or better yet, release it into the wild!
@@scowell Sure! I can make it available on Patreon. Eventually, when I get to it, it'll be released on my web site.
It's easy when you understand and know what you're doing!
@CuriousMarc - 2024-09-26
Ken Shirriff has posted an article looking inside the ferro-magnetic chip and explaining how it works, here: https://www.righto.com/2024/09/ramtron-ferroelectric-fram-die.html . Not the one that failed unfortunately, as that one was lost during the first decapping attempt. It's unlikely we'd have seen anything wrong visually anyhow.
@cambridgemart2075 - 2024-12-03
Youtube has corrupted the URL of the link! Thankfully I was able to Navigate the the blog entry which was in September 2024 for anyone trying to find it.