V5 Brain with dead ports

We currently have 6 of 8 V5 brains, still waiting on 2 more bundles. One of our brains demonstrated issues right out of the box. Last night I did further troubleshooting by writing code to turn on every port and test the V5 motors. Ports 2,6,8,9,11 are dead. The motors leds just blink when plugged into those ports. I have switched around cables and motors, I also loaded the program, motors, and cables on another V5 Brain and that one worked just fine. I am convinced that the eFuse for each of these ports is damaged.
My biggest concern is this team is about 5 weeks from their first competition and the delay that vex is sending out the brains leaves me very nervous to send this brain in for repair or replacement. We still don’t have our other 2 brains for our other teams. We have a parts coordinator who will work with Vex to find out about replacing this. In the meantime, is there anything else, i.e. firmware etc… that can be done?

We have 2 V5 Brains whos 3-wire ports are not functioning properly. Fortunately we did have 1 that worked correctly so we were able to test the same programs running on both against the same hardware on each. In this way we could see the tests work and see when they did not.

I hope that a firmware update is the solution here. I would like to try to re-flash the existing firmware to see if that fixes it but have no idea how to make that happen at the moment. I emailed support yesterday, but their email suggests that it may be multiple days before they can respond to the email.

We are on the latest firmware level that has appeared for us in VCS. Just for kicks, I downloaded pros and wrote a simple program to check the ultrasonic values and got the same result. (1.0.2).

Thanks for any help here.

One additional thought, what would be really helpful is a release schedule with a list of known issues. In this way we could work around issues till they were addressed. Right now we live in the dark, making assumptions and waisting time. Even if schedules slip, that is fine. Communication about what is being worked on will make a difference. Thanks

can you give more details please, what device did you try ? Analog or digital sensor ?

There are no “show stopper” issues we are aware of in vexos. There are some minor bugs in the VCS sdk that will be addressed in the next release.

So release a schedule of when the “minor bugs” will be fixed.

No show stopper bugs

VCS Feature List: “MuLtI fIlE sUpPoRt”

lmao, seems legit

That’s not a bug. That’s a requested feature, you know those are different right?

There are three distinct parts to programming the V5. We have vexos that provides the low level support, it doesn’t matter if you are using VCS, PROS, RobotMesh or any other development offerings, if you are controlling, for example, a motor it all goes through vexos. When I was referring to “show stopper” bugs I was specifically referring to vexos.

VCS uses another layer of software on top of vexos, that’s what we call the sdk. This implements all the C++ classes, there are some known bugs in the sdk that will hopefully be addressed soon.

Then we have the VCS application, that lets you write your program, it then compiles, links and downloads it to the brain. I agree this has some limitations in V1.0, but that’s mostly handled by another team so not much I can do there to speed up delivering new features.

For our testing we used :
vex::brain Brain;
vex::sonar rightSonar = vex::sonar(Brain.ThreeWirePort.C);
vex::pot Pot = vex::pot(Brain.ThreeWirePort.A);

the code that was used for the test was simple.
#include “robot-config.h”

int main() {
while(1) {

Brain.Screen.printAt(1, 40, "distance: %f in", rightSonar.distance(vex::distanceUnits::in));

Brain.Screen.printAt(1, 120, "Pot: %f ",Pot.value(vex::analogUnits::range8bit));



On the brain that worked, both showed values and changed either by moving a hand with in range of the ultrasonic sensor, the pot also showed values and changed with increasing or decreasing the turn on the pot…

On the brain that did not work, showed 0.000000 as a value. The detected states for the 3-wire ports were (A) Analog input 35 (0%), C & D both Digital Input High (1).

Let me know if you need more info.



Ok this is different, Left the Brain disconnected for the night.

I ran the program (above) again on the brain that was producing 0.000000 as a result, this morning after powering the unit up both the ultrasonic sensor and the pot are reporting the same values. Changing the pot by increasing or decreasing shows no change.

0.157480 = rightSonar.distance(vex::distanceUnits::in)
0.157480 = Pot.value(vex::analogUnits::range8bit)

Edit: re-running the program now reports the values at 0.000000 again.
Just reposted the entire program in the previous post, also tested with different wait times from 20ms to 500ms. In one of my earlier test passes, I also tried resetting to factory defaults (using the brain UI) with no impact.

perhaps another clue.



I contacted Vex Support, they were very helpful.
We tried a few additional tests/checks with the same result.

We have started the RMA process for this unit.

Thank you, I have been wondering how this worked but didn’t really know how to ask it.