No risk, no fun 
SOD323 is hard to find - does 0603 or 0402 fit better? Thereās more of those.
Hereās a filtered Digikey search. The URL is a hot mess, but thereās some options.
Itās been a long time since Iāve had to specify TVS diodes, and never for a stepper motor application. Iām wondering if this would be a good fit? https://www.digikey.com/en/products/detail/on-semiconductor/SZESD7241N2T5G/7221019
24V min breakdown, 48V max clamp, which is under the driverās absolute maximum rating of 50V. Itās an 0402 package.
1 Like
0402 is to small and 24V to low, 0603 fit. The min breakdown should 36V.
or
We should wait for information from staff.
1 Like
I have not a facebook account.
I get that. I only use it for stuff like SM and entering contests.
Hereās a pdf: (unfortunately have to post as zip)
linear moduleC.zip (348.4 KB)
-S
Thanks for the document.There are lots of useful descriptions in there.
Good. Hope itās helpful.
Itās beyond my skill level.
Give me a soldering iron and a parts list and Iām fine.
I have no fear of doing a cap kit or socketing some icās.
If you guys can figure it out, then great.
-S
@Toxic @brent113 39V is insufficient!
Even though the power supply is of 24V, the IC driver PCB also has a boost converter onboard, which boost up to 42V. So I would recommend at least 50V if you are going to use the diode.
Nevertheless, isnāt nowadays TL-smoother an obsolete thing for stepper motors drivers?..
1 Like
Thank you for the hint with the step-up converter.
This is a completely different construction site.
For me, itās actually about surge protection.
2 Likes
Two houses further. Somebody left something unattended. 
Oh dang. Well at least they were having fun.
I think it would be good to retrofit the protection just in case.
Hello,
I had exactly the same issue with one of my z-axis linear modules. In my opinion, the damage was caused by the excessive heat generated by the chip that was not conducted away properly and not by the lack of the protection diodes. The chip uses the chassis as a heat chunk, so the thermal connection with the chassis must be very good.
I replaced the damaged chip and the thermal gap filler that was originally installed plus I also added some thermal grease. So far I havenāt had any issue with the repaired linear module.
1 Like
For those of us less experienced with replacing ICs - these are pinless packages, did you wick the solder off and the chip popped up? Or how did you get the chip off?
And putting the new chip in - coat with flux and run a bead of solder down the edge? Or did you do it pad by pad?
1 Like
He probably has a hot air stationā¦ just heated it till he could pull the old chip offā¦ alot of times there is just enough solder left on the pads that you can throw a new chip on, heat it up and be goodā¦ if not you would apply the tiniest dot of solder paste (you can buy it in a syringe from amazon) on each pad and then put the chip on and heat itā¦ after its on use a magnifying glass to make sure you have good alignment and no shorts between pins. Then apply your heat sink (or thermal pad filler) and your good to goā¦ at least thats how I do it 
1 Like
Oh right, I almost got one some years ago but I donāt do enough IC work to justify it. Forgot those exist. I think if I had to do it in a pinch I would try a foil shield and my heat gun.
1 Like
Might work, just be careful not to roast the board (heat guns tend to move alot more air then a rework station would) and try to get the nozel of the heat gun to be about the same size as the chip. But really you can get a hot air station for like $30 on Amazon and it will save you hours of frustration and quite a bit of hair.
1 Like
This was in a discussion related to counter-emf from collapsing magnetic fields. Thereās a wiki on it: https://en.wikipedia.org/wiki/Counter-electromotive_force. Voltage is an accurate description in this example. In electrochemical circuits there appears to be different terminology Iām not familiar with, thanks for bringing that to my attention.