Update: Rail module repair = SUCCESS!

My new stepper motor driver ICs showed up. A bit of micro soldering and… SUCCESS!!!
My tests were correct, the primary culprit was the stepper motor driver IC. My snapmaker A350 is back in service.

Removing the chip: First, some Flux.

Now a proper amount of hot air to release the chip from the board.

Need to remove the old solder. Here I’m using soldering wick.

Fresh solder on the pads is applied. Sometimes this isn’t necessary as some chips come presoldered with solder balls. The new chips I got does not have solder balls attached.

New chip. (You wouldn’t believe the packaging they sent this with…)

New chip micro soldered in place.

Cleaned up, reassembled on to the motor and added a new thermal pad.

Tested. I’d post a video, but it won’t let me.
Now to print something. :slight_smile:


Dude. Nice work. That is some clean soldering work, I’m impressed. Do you do lessons? Hahaha.


I have considered doing a YouTube channel, but I’d get lost in the sea of tutorials that already exist out there.
I am considering offering a repair service on these.


that is some nice work, i always have trouble applying the paste on those tiny pads.

Successful 6+ hour Halloween decoration print. Little stringing in some areas due to my own fault for not adding supports. Little more fine-tuning and I think it’ll be great. Other than that I’m happy with the results.


That print looks very nice, particularly the detail around the teeth.

Was it yourself, or another member what was toying with the idea of using a silent driver IC? Or is it not that simple?

Not that easy, if you wanted to switch to silent steppers you would need to rebalance the power/torque/microstepping of the machine.

1 Like

It’s possible. However, it’s not as simple as just replacing the chip. It’ll require another redesigned PCB. I’m working on one. Once completed I’ll cut the prototype out on my cnc. This kind of development will take time, especially considering I work full time and will be building this in my spare time (if I get any).


I am the other guy that posted on my success fixing linear rails with blown stepper driver and other ICs. Also trying out the TMC silent drivers. As mentioned, it is non-trivial to tune them to be quiet and not skip steps.


Is there any possibility to use copper heat sink on a chip? Something like that.

I don’t see why not. I can’t remember where on the machine it was, but something was bonded to the aluminum extrusion, shame there wasn’t a way to get that driver in contact with the aluminum.

Ideally, the heatsink should make contact with the PCB pad that the IC is soldered on, not on the IC itself. The plastic package on the IC is a much worse conductor of heat than the copper on which the IC is soldered on. The Trinamics stepsticks have it correct.

I think that all my linear module are without heatpad and one just broke up, what can I look for for an IC replacement?

The housing inside would need to be removed and cut to make room for it.

It does. The blue thermal heat pad sits on the IC chip and makes contact here on the inside of the rail housing.

Like I said above, it would need to be cut to make room for a heat sink and some testing done to make sure it doesn’t interfere with the rail’s function.


Has some one replaced the original TB67S109AFTG 50V/4A stepper motor driver with a trinamic one? I would use a KINGPRINT TMC5160 steppermotor StepStick wit 40V max 4,4A becase of the same ampere rating and the 24V only power suply of the SM2.

Hello Geared I wouldn’t do it, becase the heat sink use air for the heat removal, there is no fan in the Rail module and the air volume is very smal. I think Snapmakers idea was to use the hole aluminium of the rail to tansfer the heat from the stepper motor driver IC to the outside. I think it is better to replace this plate with a stronger one adapted to the new stepper motor driver surface. It can be also copper used instead of aluminium.

The use of a tmc5160 isn’t as easy as swapping the chip, it would require a whole new PCB design. Which is something I am working on.
As far as the heat sink goes, the original is just a flat plate. Any heat would need to radiate back across the chip to dissipate into the rail mount. Not ideal. With a copper finned heat sink which would conduct heat even better than the aluminum plate even without air flow would be preferable.

The exchange of the motor driver to a TMC one is never easy, but Trinamic has a modul called SilentStepStick (https://www.trinamic.com/support/eval-kits/details/silentstepstick/) how was build for ohter 3D printer. I want to adapted this board of the TMC 5160, Version 1.2, freely available on the market to fit in the free space of the removed second board on the linear module and put all with some wire and glue together and test it. (if its work its ok, its inside the module nobody would ever see this again).

I have looked into the 5160 and it’s not suitable for this application. The 5160 stepper resolution is set by the controler, the original chip the step is set by making a combination of pins high or low on the rail board itself.