on today's makers mashup i'm going to try to save your step sticks from certain doom in the skr2
okay so in today's video i'm hopefully going to save you from blowing up an entire set of
step sticks in your new skr2 and i suggest you share this video with as many people as possible
we really need to get the word out here because if you buy this brand new board and you would install
a tmc 2209 the exact way that they say in the current existing documentation you're almost
assured to blow up all of the step sticks that you've installed into the skr2 okay with the psa
out of the way let's talk about what happened here in the last 24 hours so i woke up this morning and
i got an email from big tree tech basically i'm sorry to disturb you our company has seen that
you've posted a video on youtube please listen to me here please stop using the big tree tech skr2
in your hand because now our company has found skr2 tmc2209 can't be used for the components
of this product now it has been updated i will reissue the updated big tree tech skr2 for you
later also please provide your address i will ship it for you as quickly as possible sorry for the
inconvenience all right so i'm like what is going on so i emailed big treetech back i said i just
ordered 20 of these we use them in our 3d printers here and we're selling them on layerfuse.com what
is going on so they replied basically back and said reach out to my contact and sales and they'll
worry about a refund on this so i did reach out to my contact in sales and he was actually
far more helpful than the original email that i got in talking with mike who's my contact there
at big tree tech he said we found a problem with the board it's related only to some boards and
only the tmc2209s or other ones that are using those uh extra pins for the sensorless homing
so i said well can i get some steps to reproduce how do i know that i have bad boards here and he
said i can't really help you with that but he gave me another contact mr sue at big tree tech and i
reached out to him via skype and we had a short conversation about what the issue was because
what i wanted to do was to identify whether or not my boards were affected because mike
said he really wasn't clear on if this was every board or only some boards i'd seen a lot of
different people with comments in the last video and that saying that they had problems with the
2209s and they weren't working in the board matter of fact one person said he he received a whole set
of bad step sticks so i think that was really where this started was that there was uh people
that were having a problem they were reporting it to support so i asked mr sue hey can you give me
some steps to reproduce this issue so that way i can actually see where the problem is breaking
down he said sure give me a few minutes came back and he gave me this document here that i'm going
to share with everybody here and there's going to be a link down in the description so you can
download it in the event that big tree tech hasn't posted it on their website just yet so essentially
there was no steps to reproduce what they did was they gave me what the fix was and based on the fix
and how this plays out it really does sound like what happens is that if you do not attach these
two grounds together on the board itself what's going to happen is at some level the step sticks
are basically going to fry and it affects all the step 6 on the board not just the one tmc 2209 but
everything that's been installed and that would go along with what we were seeing which was a few
people that said hey i had a whole set of bad step sticks so the step sticks weren't bad but the skr2
actually fried the step sticks which made them unusable and then what was happening was
is on the screen of the display you would see that there was a tmc connection error or if you
ran the 122 m command it would basically come back and say that there was no connection
to the tmc drivers so luckily i had not installed the step sticks yet into this board
i'd been using the sd card that i had and i loaded it onto the main board but i didn't install any
of the step sticks and that really was my saving grace in that i didn't blow up any step sticks or
have any problems and i followed the directions in this document that i'm sharing with you
so this is a work around that you can do but i really recommend that once big tree tech does get
these boards uh fixed and out in the marketplace that you go ahead and get a replacement board my
concern with this fix is just that if a wire comes loose then you're gonna fry all your step sticks
in the board itself so with all that said let's get to work so the fix for this is really pretty
simple we're going to connect a wire from the ground on the end stop switch to the ground and
the closed loop stepper then inside the firmware we need to disable the new functionality that is
to prevent you from frying your step sticks if you insert them incorrectly so basically if they're
twisted around so the top is at the bottom and the bottom to the top what happens if you enter
them reversed it would fry your step stick and in this particular case yes the irony is so thick
that if you insert them the right way and have this functionality installed with the tmc2209
you'll fry all the step sticks in your main board okay so here we have my skr2 and i've already got
the step sticks installed now you can see here i've got on these two ports and this is normal for
an x301 uh we've got in our x and y ports we have our tmc2209 and then over here i've got
two tmc 2208s usually i have some 2225s in there but these are some older tmc 2208s so if i had a
problem with this board i would be frying an old step stick that i'm not actively using uh
i was really hoping i didn't fry any and we didn't so let's get into what this fix is so what we're
going to basically do is over here we've got the end stops and the center pin of these x and y end
stops is the ground then what we're going to do is we're just going to add a jumper to the third pin
of the closed loop steppers here and what that does then is it joins these two grounds together
now alternatively and i don't like this solution only because the wiring becomes a bit messy is
that you can take these same grounds that are the center pin grounds here and then you can ground
them here on your power and that documentation does cover that i think the two jumpers here are
really pretty easy your tmc 2209s come with these type of jumper wires anyhow so it makes it really
simple to just take one of those and use that instead of a spy connection you can go ahead
and just use this to link the grounds so i've got a couple wires that i was using earlier today and
what we're going to do is we're just going to take this center pin i'm going to put one jumper there
and we'll do another one for the y and then we just want to link them back so the third pin in
here on the closed loop stepper we'll add that one and then the same thing here on the third pin in
we add the ground here so as you can see what we've got is a ground from these closed loop
stepper ports to the center pin on the end stops here now once you've got this installed you're
bored to act like you would expect you get the sensorless homing the steppers move just fine and
your display and everything works now i've got a little bit of a timing issue on this display that
i didn't adjust in the firmware so it's going to look a little funky but that's pretty normal for
these uh inexpensive displays it's just a fix in the firmware so i'm going to turn the board on now
and you can see we get the marlin bug fix and this is the same firmware that big tree tech
has on their repo and it says skr2 ready you can see there's no tmc connection error there
and we're going to go down to motion
and we'll move the x
and you can see the stepper over here is moving just fine
and then we're going to go up here and we'll try the same with the y
and this stepper is moving just fine
and we're going to try our z now this is using the 2208s
and there we go that one's moving fine as well
so as you can see here once you put these jumper wires in place the tmc 2209s work just fine
and you also have your tmc 2208 or if you have 2225s in your x301 build it'll work just fine
okay as you can see the fix for this is really simple but like i said my concern with all of this
is that if one of these wires do come loose then you're gonna end up frying the entire board but
if you already have this board and you simply just want to use it you can go ahead and use
these jumper wires the same way i did and that will go ahead and fix your problem and prevent
your step 6 from blowing up so the choice is really yours and i do want to thank big tree tech
for at least reaching out and letting me know immediately so i can put this video together
and let all of you know for those of you that have already had a problem with this i'm really sorry
to hear that please reach out to big tree tech i they've been really receptive about this issue
and doing more or less like a recall on these boards and trying to replace them for end users
so i have to say that they're really trying to stand behind this issue and get it fixed
so please reach out to them if you're having a problem but this fix as you see does work and
does allow you to use the tmc2209s or any other driver that is using that sensorless homing and
if you're using another driver like a tmc2208 presumably we're not having an issue with that i
haven't heard any problems with those uh sorts of installations it's only the sensorless homing so
at least it's very limited so hopefully a lot of people don't blow up their
step sticks using the new skr2 so with that it's gonna bring the end of today's video if you liked
it make sure you mash that like button and please share this video as much as possible i really want
to make sure that we get the word out just to save somebody some money and aggravation on the tmc2209
and don't forget to subscribe so you don't miss any update videos on the skr2 like this one here
so with all that said i want to say thanks again for watching and we'll see you all next time
you