v5 Brain Issues

My team has possession of a single v5 Brain (borrowed from local team) and it seems like, new out of the box, the Brain is malfunctioning. I get an error stating that there is an issue with memory, the LCD glitches while the program is running, or the Brain freezes and the LCD is glitched and the program ceases to run. It seems like the only fix for this is to hard reset (unplug battery) as not even the power button is responsive. Has anyone encountered an issue like this? This is our first experience with the new system and hope that it is uncommon.

I personally haven’t experienced it, but there are lots of people on the forum who say that they have. I recommend trying to contact vex for more support or a replacement kit.

Also it is relatively common, it is just a glitch with the new system.

Is the error a memory access error (which is a segfault)?
Can you post your code?

Sounds like user program with un-initialized pointers or something. If you see a red warning rectangle, that’s the os trying to protect itself.

The code I’ve ran does not include any pointers. Besides that, I’ve even experienced the same issues when running the tank drive example code provided by Vex.

Ok, could you explain a little more about happened when you saw this ?

was that a red box with an error message ? or something else ?


Here is a picture of the red box error, I have found this can be resolved by redownloading the code

And here is the screen glitch, which can only be resolved by unplugging and plugging in the battery:

ok, my guess is that this is a hardware fault on the V5 brain. The second image showing lines on the screen is something we have never seen before, if that is happening when just running the built in drive or clawbot programs (or at any other time) then I think it’s an issue with a bad memory IC or something like that. The first message comes from user code that is trying to access protected memory, that’s usually caused by bad pointers, but a hardware fault in the memory system could also theoretically cause it to happen.

Best plan is to contact vex support and they can arrange for a replacement. When you return this unit please be sure to label with the problem so engineering can do further analysis as to why it has failed.

@jpearman - we had that second screen also yesterday (although it was blue vertical on a black background). We weren’t running any programs at the time. I also emailed support with a video showing all sorts of random v5 brain glitches (no response yet). When I called they told me to run standalone update for a fix but when we did that it said we were already up to date. Can we do an update override or some other “fix”? Brain works sometimes, not others… hate to send it in and have to wait weeks/months for another (just finally got this last week).

I’ll send a PM.


Thanks for the response! I’ll be sure to contact vex and leave a description of the issues with the Brain in the box I ship with

going to send a PM, we can try one more thing first.

Hi, was this issue resolved eventually?

Our team is also experiencing this problem and we have a competition soon…

Which problem specifically ?

The issue mentioned above regarding the V5 Brain. Our school has ordered 3 brains and 2 have the problem above where after a few minutes of use, they become unresponsive and sometimes display the blue bar pattern (identical to the image linked above). The power button does nothing and we have to power cycle by removing the battery to restart the Brain, upon which the same problem happens again. Anything running on the Brain stops immediately and the Controller reports a lost connection.

We’ve tried to update firmware and VEXos, which fail most of the time because the brain freezes while this is happening; however we did succeed once I believe. The problem is probably not the battery as we have tested 3 different fully charged batteries including the one used to power the working Brain. In addition the problem happens regardless of whether anything is plugged in to the ports, or if a program is running. Problem is so severe that once the brain was unable to boot to the home screen, and instead reported an “Invalid Table Assets” error which required us to completely reinstall the os.

This is really urgent for us as we are an overseas team (meaning shipping takes a hell of a long time) and have a competition very very soon…