Answers.Body: <p>Most people with port problems have port C failure. I had similar issue. In my case it was factory defect: SMD chip (U26 on board, see image and HW dev kit pdfs) was soldered with a twist and had two legs broken, but they touched the chip and sometimes signal was getting through. They are used for tacho input. So in some modes when it runs fullspeed it works OK (remote control or built-in motor control), but when it is required to turn for degrees or rotate with a given speed it just spins fullspeed without a stop since it does not getting tacho from the connected motor.</p>
  <p><a href="https://i.sstatic.net/CvBNa.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/CvBNa.png" alt="buggy board" /></a></p>
  <p>I replaced the chip (74HC2G14GW-G) and now everything works fine. I don't think they solder chips by hands, so it could be some defective batch.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-11-18T12:23:51.793Z
Answers.Text: When I saw the same thing with another brick I figured out that the plastic shell is crushing the chip. It holds PCB right in the place of U26, which it right in the middle of the side.  Bad engineering :( Had to remove the fixer.
Answers.UserDisplayName: Konstantin Dombrugov
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-01-17T21:09:44.413Z
Answers.LastActivityDate: 2021-01-17T21:09:44.413Z
Answers.UserDisplayName: Konstantin Dombrugov
Answers.Body: <p>In the mean time Lego has confirmed that the brick was broken and replaced it.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-05-26T11:58:11.913Z
Answers.Text: Did this resolve an issue with driving motors as well?
Answers.UserDisplayName: Alex
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-05-27T15:05:45.440Z
Answers.Text: Cheers for the update jboss, glad you were able to get to the bottom of it, and LEGO replaced the faulty item.
Answers.UserDisplayName: Zhaph - Ben Duguid
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-05-25T07:09:59.720Z
Answers.LastActivityDate: 2020-05-25T07:09:59.720Z
Answers.UserDisplayName: jboss
Body: <p>Yesterday I had the basic driving robot with two large motors, but I could not get both motors running at the same time. I had the tank control programming block, with both motors set to 50% and when running the program both motors would start and one would continue spinning, but the other would stop after only 1 or 2 degrees of rotation.</p>
  
  <p>First I thought it was a problem with the motor, so I replaced it with another motor from another set, but the problem remained. When I switched the ports it was the other motor that would not keep running. I tried different ports, changing the cables and restarting the brick but nothing helped. Checked the rechargeable battery to see if it was a power issue, but that was full. I did this in a class with several other EV3 sets using both large motors and none of the others had this problem.</p>
  
  <p>I then used the programming block for a single large motor and tried both separately and that worked fine. But when I put two of those blocks after each other to start the motors sequentially again the second would not run after an initial click.</p>
  
  <p>When I wanted to troubleshoot it further after I got home everything worked fine, which makes it even stranger. That also suggests it was not the battery box as mentioned in <a href="https://bricks.stackexchange.com/questions/8775/problem-with-running-two-xl-motors-motors">this post</a>.</p>
  
  <p>So I hope maybe someone has seen this before and can tell me why this happened and what to do should it happen again.</p>
  
  <p>Thanks!</p>
  
  <p>EDIT:
  I found the faulty EV3 (it was number 9, not number 6....). So I was able to do more troubleshooting. Attached a screenshot of the various programs I tried with comments.</p>
  
  <p>It looks like port C is consuming more power than the other ports (motor runs at a significantly higher rpm). And this shuts down any motor running at the same time through one of the other ports. combining two of the other ports (e.g. A and D) works fine.</p>
  
  <p>Any thoughts on how this can happen?</p>
  
  <p><a href="https://i.sstatic.net/VKt7P.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/VKt7P.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.sstatic.net/sE2k7.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/sE2k7.png" alt="Program"></a></p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-12-19T09:10:57.403Z
Comments.Text: Hi jboss and welcome to Bricks.SE! Can you post a screenshot of your program, so that we can see what exactly is happening?
Comments.UserDisplayName: zovits
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-12-19T11:34:18.680Z
Comments.Text: I'm not 100% sure it was like this (it was yesterday and everything is removed and taken apart again) but it was the basic driving robot.
Comments.UserDisplayName: jboss
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-12-19T18:42:37.073Z
Comments.Text: Maybe try another battery pack?
Comments.UserDisplayName: Alexander O'Mara
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-12-20T08:35:52.763Z
Comments.Text: I tried another battery pack, no effect. I also tried resetting the brick, no effect.
  But when I used motor control from the menu on the brick itself I could run both B and C simultaneously.
Comments.UserDisplayName: jboss
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-12-20T08:46:43.410Z
Comments.Text: And another possible cause, I updated the firmware of the brick, but that also made no difference.
Comments.UserDisplayName: jboss
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-12-20T14:06:10.537Z
Comments.Text: I'd say if you can reliably reproduce the issue (use the same program, same PC and same motors with another EV3), then the EV3 must be faulty and you should contact LEGO for assistance in the form of a fix or a replacement.
Comments.UserDisplayName: zovits
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-12-21T08:24:19.107Z
Comments.Text: Good point, thanks. With the same motors, cables, PC and USB cable but a different EV3 it worked fine. SO I'll contact Lego support. The only thing that still puzzles me is that when I run the motors from the motor control in the brick menu it works fine as well. But hopefully Lego support cna explain that as well.
Comments.UserDisplayName: jboss
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2020-05-23T23:12:00.830Z
Comments.Text: Maybe use the Move Steering block instead.
Comments.UserDisplayName: Random Person
Tags: <ev3><motor>
Title: Mindstorms EV3 unable to drive two motors simultaneously
UserDisplayName: jboss
ThreadText: # Mindstorms EV3 unable to drive two motors simultaneously
  
  (Asked by: username_0 on 2019-12-19)
  
  Yesterday I had the basic driving robot with two large motors, but I could not get both motors running at the same time. I had the tank control programming block, with both motors set to 50% and when running the program both motors would start and one would continue spinning, but the other would stop after only 1 or 2 degrees of rotation.
  
  First I thought it was a problem with the motor, so I replaced it with another motor from another set, but the problem remained. When I switched the ports it was the other motor that would not keep running. I tried different ports, changing the cables and restarting the brick but nothing helped. Checked the rechargeable battery to see if it was a power issue, but that was full. I did this in a class with several other EV3 sets using both large motors and none of the others had this problem.
  
  I then used the programming block for a single large motor and tried both separately and that worked fine. But when I put two of those blocks after each other to start the motors sequentially again the second would not run after an initial click.
  
  When I wanted to troubleshoot it further after I got home everything worked fine, which makes it even stranger. That also suggests it was not the battery box as mentioned in [this post](https://bricks.stackexchange.com/questions/8775/problem-with-running-two-xl-motors-motors).
  
  So I hope maybe someone has seen this before and can tell me why this happened and what to do should it happen again.
  
  Thanks!
  
  EDIT:
  I found the faulty EV3 (it was number 9, not number 6....). So I was able to do more troubleshooting. Attached a screenshot of the various programs I tried with comments.
  
  It looks like port C is consuming more power than the other ports (motor runs at a significantly higher rpm). And this shuts down any motor running at the same time through one of the other ports. combining two of the other ports (e.g. A and D) works fine.
  
  Any thoughts on how this can happen?
  
  [![enter image description here](https://i.sstatic.net/VKt7P.png)](https://i.sstatic.net/VKt7P.png)
  
  [![Program](https://i.sstatic.net/sE2k7.png)](https://i.sstatic.net/sE2k7.png)
  
  **Tags:** ev3, motor
  > **Comments:**
  > **username_1**: Hi jboss and welcome to Bricks.SE! Can you post a screenshot of your program, so that we can see what exactly is happening?  
  > **username_0**: I'm not 100% sure it was like this (it was yesterday and everything is removed and taken apart again) but it was the basic driving robot.  
  > **username_2**: Maybe try another battery pack?  
  > **username_0**: I tried another battery pack, no effect. I also tried resetting the brick, no effect. But when I used motor control from the menu on the brick itself I could run both B and C simultaneously.  
  > **username_0**: And another possible cause, I updated the firmware of the brick, but that also made no difference.  
  > **username_1**: I'd say if you can reliably reproduce the issue (use the same program, same PC and same motors with another EV3), then the EV3 must be faulty and you should contact LEGO for assistance in the form of a fix or a replacement.  
  > **username_0**: Good point, thanks. With the same motors, cables, PC and USB cable but a different EV3 it worked fine. SO I'll contact Lego support. The only thing that still puzzles me is that when I run the motors from the motor control in the brick menu it works fine as well. But hopefully Lego support cna explain that as well.  
  > **username_3**: Maybe use the Move Steering block instead.  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_4 on 2021-01-17. Score: 4
  
  Most people with port problems have port C failure. I had similar issue. In my case it was factory defect: SMD chip (U26 on board, see image and HW dev kit pdfs) was soldered with a twist and had two legs broken, but they touched the chip and sometimes signal was getting through. They are used for tacho input. So in some modes when it runs fullspeed it works OK (remote control or built-in motor control), but when it is required to turn for degrees or rotate with a given speed it just spins fullspeed without a stop since it does not getting tacho from the connected motor.
  
  [![buggy board](https://i.sstatic.net/CvBNa.png)](https://i.sstatic.net/CvBNa.png)
  
  I replaced the chip (74HC2G14GW-G) and now everything works fine. I don't think they solder chips by hands, so it could be some defective batch.
  
  > **Comments:**
  > **username_4**: When I saw the same thing with another brick I figured out that the plastic shell is crushing the chip. It holds PCB right in the place of U26, which it right in the middle of the side.  Bad engineering :( Had to remove the fixer.  
  
  ---
  
  ### Answer by username_0 on 2020-05-25. Score: 2
  
  In the mean time Lego has confirmed that the brick was broken and replaced it.
  
  > **Comments:**
  > **username_5**: Did this resolve an issue with driving motors as well?  
  > **username_6**: Cheers for the update jboss, glad you were able to get to the bottom of it, and LEGO replaced the faulty item.  
  
  ---
  
  