# Circuit diagram linear module? or why my linear module is broken **URL:** \ **Category:** Snapmaker 2.0 (3-in-1)\ **Created:** [October 17, 2020, 4:08pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584 "2020-10-17T16:08:21Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Toxic](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/toxic/32/6974_2.png) [@Toxic](https://forum.snapmaker.com/u/Toxic)\ **Post date:** [October 17, 2020, 4:08pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/1 "2020-10-17T16:08:21Z")
Is there a circuit diagram of the linear module. According to the print on the circuit board, two diodes are missing from the motor to protect the driver from overvoltage. Is that wanted or is it a production error in the assembly. As I understand it, the lack of diodes can cause the motor driver to experience an overvoltage under a slightly higher load (through short movements) and thus destroy it. So that a damage pattern occurs as with me, that the axis is a total failure. ---
**Author:** ![buzzplop](https://avatars.discourse-cdn.com/v4/letter/b/919ad9/32.png) [@buzzplop](https://forum.snapmaker.com/u/buzzplop)\ **Post date:** [October 17, 2020, 4:18pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/2 "2020-10-17T16:18:53Z")
Can you provide a picture? ---
**Author:** ![Toxic](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/toxic/32/6974_2.png) [@Toxic](https://forum.snapmaker.com/u/Toxic)\ **Post date:** [October 17, 2020, 4:49pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/3 "2020-10-17T16:49:11Z")
the desired picture, please šŸ˜ ![20201017_183606](https://us1.discourse-cdn.com/flex022/uploads/snapmaker/original/2X/1/12c2e5148e8adb493d682c196646759564f70db5.jpeg) note the blown hole in the circuit. There the magical blue smoke came out. ---
**Author:** ![Toxic](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/toxic/32/6974_2.png) [@Toxic](https://forum.snapmaker.com/u/Toxic)\ **Post date:** [October 17, 2020, 4:59pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/4 "2020-10-17T16:59:36Z")
I am of the opinion that the protective diodes at the output to the motor windings are missing. They can be seen on the right in the attached circuit diagram ![L298standard](https://us1.discourse-cdn.com/flex022/uploads/snapmaker/original/2X/2/261b90ebbfb6091e29e68127a6232991831e358e.gif) ---
**Author:** ![Atom](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/atom/32/5608_2.png) [@Atom](https://forum.snapmaker.com/u/Atom)\ **Post date:** [October 18, 2020, 3:24am UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/5 "2020-10-18T03:24:11Z")
Interesting, SM didnā€™t put flyback diodes on the cooling fans eitherā€¦ though this seems like a much larger design flaw. ---
**Author:** ![Toxic](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/toxic/32/6974_2.png) [@Toxic](https://forum.snapmaker.com/u/Toxic)\ **Post date:** [October 18, 2020, 6:51am UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/6 "2020-10-18T06:51:42Z")
I took another picture of the circuit exploding. So that you can see correctly that it is a defect and not a production hole. You can see the broken edges nicely. Since most stepper drivers have an integrated overload protection at too high a temperature or too high currents, only overvoltage is an option for me. I also see the danger with the fan motors. There, however, the stress may not be so great because there is no reversal of the direction of rotation and the load changes are not so rapid. ![2020-10-18-084157](https://us1.discourse-cdn.com/flex022/uploads/snapmaker/original/2X/7/7e3d9f63704bdb91d77ad69fba3e70515c7d2c0b.jpeg) ---
**Author:** ![sdj544](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/sdj544/32/11365_2.png) [@sdj544](https://forum.snapmaker.com/u/sdj544)\ **Post date:** [October 18, 2020, 7:04am UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/7 "2020-10-18T07:04:10Z")
Iā€™m wondering whether the decision to put the circuits inside the module was a mistake. Stepper motors create a lot of heat. Why not place the driver inside the controller or as part of the splitters or as itā€™s own separate unit? Perhaps thereā€™s a way to retrofit this? -S ---
**Author:** ![brent113](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/brent113/32/11114_2.png) [@brent113](https://forum.snapmaker.com/u/brent113)\ **Post date:** [October 18, 2020, 7:17am UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/8 "2020-10-18T07:17:31Z")
Hey dumb question here, but since Iā€™m having trouble reading the IC markingsā€¦ Is that the canbus mcu and not the stepper driver? I was under the impression the stepper driver was an a3988 which I donā€™t see those markings on that chip. That chip looks like it has way too many pins to be the stepper driver. ---
**Author:** ![Toxic](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/toxic/32/6974_2.png) [@Toxic](https://forum.snapmaker.com/u/Toxic)\ **Post date:** [October 18, 2020, 7:34am UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/9 "2020-10-18T07:34:41Z")
@brent113 I once marked the conductors from the circuit to the motor connection in color. Several pins are brought together on the circuit to reduce the current load on the individual bond wires. ![2020-10-18-092649](https://us1.discourse-cdn.com/flex022/uploads/snapmaker/original/2X/6/63317036848221ca33f6cfbe07e0bd2b8a48fa9d.jpeg) The designation on the circuit is: 5109AFTG 1921H EQ9644 JAPAN ---
**Author:** ![Toxic](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/toxic/32/6974_2.png) [@Toxic](https://forum.snapmaker.com/u/Toxic)\ **Post date:** [October 18, 2020, 8:25am UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/10 "2020-10-18T08:25:56Z")
@sdj544 Integrating all the control electronics into the module is okay. The housing is made of aluminum, which sufficiently dissipates the heat from the engine. Attempts were also made to dissipate the waste heat from the stepper driver, but in my opinion this was not optimal. The silicone thermal pad has a tendency to slip. A longer ribbon cable between the two boards would allow the stepper board to be securely mounted on the housing. Or make the mechanical connection of the two boards elastic, so that a spring pressure is always applied which presses the stepper board against the housing. Conductive paste would be sufficient in both scenarios. ---
**Author:** ![brent113](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/brent113/32/11114_2.png) [@brent113](https://forum.snapmaker.com/u/brent113)\ **Post date:** [October 18, 2020, 4:45pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/11 "2020-10-18T16:45:19Z")
> [@Toxic](#): > > 5109AFTG _Alert: rambling ahead as I try and understand what youā€™ve already figured out. No conclusions drawn:_ Ah, itā€™s a TB67S109AFTG stepper driver. Thanks for that. [Datasheet and Application Note here](https://toshiba.semicon-storage.com/us/semiconductor/product/motor-driver-ics/stepping-motor-driver-ics/detail.TB67S109AFTG.html), if you havenā€™t found it yet. ![image](https://us1.discourse-cdn.com/flex022/uploads/snapmaker/original/2X/a/a9a4db2889b60be2a348887541139e4f9fd2f29a.png) Those two empty solder pads you traced are for the OUTA+/- and OUTB+/- pins to the motor. The typical application does not have clamping diodes, so this design closely matches the reference design: ![image](https://us1.discourse-cdn.com/flex022/uploads/snapmaker/original/2X/4/43bd204a89c03978034d5f04158949d4a298cbec.png) Flyback handling is done by the driver internally: ![image](https://us1.discourse-cdn.com/flex022/uploads/snapmaker/original/2X/b/b3b018082dadd845e5452fb57dde79867d635e81.png) Anyways, about the only thing I canā€™t tell yet is if the power supply is fused like the datasheet recommends. Other than that the design seems fine. ---
**Author:** ![Toxic](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/toxic/32/6974_2.png) [@Toxic](https://forum.snapmaker.com/u/Toxic)\ **Post date:** [October 18, 2020, 4:51pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/12 "2020-10-18T16:51:49Z")
Thanks for the Datasheet. I must read it. edit: From Datasheet. ā€œWhile a motor is rotating, there is a timing at which power is fed back to the power supply. At that timing, the motor current recirculates back to the power supply due to the effect of the motor back-EMF. If the power supply does not have enough sink capability, the power supply and output pins of the device might rise above the rated voltages. The magnitude of the motor back-EMF varies with usage conditions and motor characteristics. It must be fully verified that there is no risk that the TB67S109A or other components will be damaged or fail due to the motor back-EMF. When a motor reverses direction, stops, or abruptly slows down, current flows back to power the motor due to the effect of back emf. When the power sink capacity of the power supply is small, the motor output of the device is increased Supply and output pins can experience conditions in excess of their absolute maximums. To avoid this problem, Consider the effect of back EMF in system design.ā€ That would explain why the module failed precisely on the part with many short internal structures. If the cable and the connectors are not laid out correctly, loose contact. And 47ĀµF as a block cap? ---
**Author:** ![Streupfeffer](https://avatars.discourse-cdn.com/v4/letter/s/f9ae1b/32.png) [@Streupfeffer](https://forum.snapmaker.com/u/Streupfeffer)\ **Post date:** [October 18, 2020, 6:06pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/13 "2020-10-18T18:06:58Z")
Based on the EMF thing, what diodes would you reccomend? I dont like verry mutch to start soldering in a Product this expensive but if it stopts it from becoming scrap ill do it if need be. Hopefully we get a statement from SN at some pointif this becomes a bigger/major problem. ---
**Author:** ![Toxic](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/toxic/32/6974_2.png) [@Toxic](https://forum.snapmaker.com/u/Toxic)\ **Post date:** [October 18, 2020, 6:17pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/14 "2020-10-18T18:17:20Z")
According to the design, anti-parallel Zener diodes were provided there. I canā€™t say which it should be now. For this we would have to see the original circuit diagram of this layout. ---
**Author:** ![brent113](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/brent113/32/11114_2.png) [@brent113](https://forum.snapmaker.com/u/brent113)\ **Post date:** [October 18, 2020, 6:23pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/15 "2020-10-18T18:23:06Z")
> [@Streupfeffer](#): > > the EMF thing Just to be clear here, EMF is the old term for what we now generally call ā€œvoltsā€. Sounds fancy though. Short for electromotive force, back from before the unit getting renamed to honor Alessandro Voltaā€™s work. Literally - the ā€œforce that moves electronsā€. ---
**Author:** ![Toxic](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/toxic/32/6974_2.png) [@Toxic](https://forum.snapmaker.com/u/Toxic)\ **Post date:** [October 18, 2020, 6:23pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/16 "2020-10-18T18:23:24Z")
from datasheet: If your design includes an inductive load such as a motor coil, incorporate a protection circuit into the design to prevent device malfunction or breakdown caused by the current resulting from the inrush current at power ON or the negative current resulting from the back electromotive force at power OFF. IC breakdown may cause injury, smoke or ignition. Use a stable power supply with ICs with built-in protection functions. If the power supply is unstable, the protection function may not operate, causing IC breakdown. IC breakdown may cause **injury, smoke or ignition**. I canā€™t afford a private firefighter. šŸ˜ šŸ‘Øā€šŸš’ ---
**Author:** ![sdj544](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/sdj544/32/11365_2.png) [@sdj544](https://forum.snapmaker.com/u/sdj544)\ **Post date:** [October 18, 2020, 6:26pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/17 "2020-10-18T18:26:40Z")
Hopefully this link works right. The preview is showing up strangely. Someone on FB has done some testing on his module: > **[Facebook Groups](https://m.facebook.com/groups/2627767230570021?view=permalink&id=4130968416916554&anchor_composer=false)** > > \[Official\] Snapmaker - New Kickstarter Project has 15,691 members. Welcome! -S ---
**Author:** ![brent113](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/brent113/32/11114_2.png) [@brent113](https://forum.snapmaker.com/u/brent113)\ **Post date:** [October 18, 2020, 6:27pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/18 "2020-10-18T18:27:59Z")
> [@Toxic](#): > > injury, smoke or ignition Itā€™s no fun if thereā€™s no possibility of injury, smoke, or ignition šŸ¤£ That circuit symbol on the PCB silkscreen is for a TVS diode, yes, literally back to back zeners. Something like this would be typical. Given the 24V application limit that may be able to be reduced, but you generally want some headroom. Also I havenā€™t confirmed the pad size. > **[BZB100A,115 | Digi-Key Electronics](https://www.digikey.com/en/products/detail/nexperia-usa-inc/BZB100A-115/2697356)** > > Order today, ships today. BZB100A,115 ā€“ Clamp Ipp Tvs Diode Surface Mount SOD-323 from Nexperia USA Inc.. Pricing and Availability on millions of electronic components from Digi-Key Electronics. ---
**Author:** ![Toxic](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/toxic/32/6974_2.png) [@Toxic](https://forum.snapmaker.com/u/Toxic)\ **Post date:** [October 18, 2020, 6:34pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/19 "2020-10-18T18:34:07Z")
Housing size SOD323 fits. Only i would look for 40V types ---
**Author:** ![Toxic](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.snapmaker.com/toxic/32/6974_2.png) [@Toxic](https://forum.snapmaker.com/u/Toxic)\ **Post date:** [October 18, 2020, 6:49pm UTC](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584/20 "2020-10-18T18:49:52Z")
I have not a facebook account. [Next page](https://forum.snapmaker.com/t/circuit-diagram-linear-module-or-why-my-linear-module-is-broken/10584.md?page=2)