Cortex Reset?

Hello everyone, once again I have a problem-- though it’s seeming more like a curse.

While I will attempt to describe the issue in as much detail as I can, its nature is so unpredictable I will have a hard time giving exact results.

Our robot, after varying lengths of time, and various amount of stress (sometimes after lifting 5 stars, sometimes after moving an inch) seemingly resets. The Robot and Game lights on the Cortex both display a fast blinking yellow-- VERY occasionally the familiar slow blinking red of a disconnect. Thus far, we have tried essentially everything we can deduce could be part of the issue-- our cortex battery is securely strapped on to the bot, plugged into a cable extender which is zip-tied to the cortex, our key has been moved up and away from wires (though it is still touching metal, now that I think about it), and we have removed our IME’s, for fear of static discharge messiness. I am unconvinced this is a VEXNET issue, seeing as our lights do not normally display the “lost connection” flashes. I believe it is along the lines of some short or charge resetting the Cortex. As far as I know, this can be caused by some exposed wire on somewhere on the robot body, (which I have been unable to find, after thorough searching) or a static shock entering the Cortex through some other exposed conductor (normally the IME’s). I have redownloaded the master code, to no seeming avail.

If anyone has any ideas for me to try, I would be very grateful.

In order to rule a VEXNet issue, try driving around with the orange USB A to A cable and see if the problem persists.

Robot (7.2V) batteries sometimes have loose connections internally that can disconnect with the motion of the robot. Try a different battery or 2 and see if the problem persists.

If you have a 9V battery (backup battery) then loose robot batteries shouldn’t be causing a reset…
Do you have a 9V connected? If you do it may be worth double checking that it is full/working.

I do have a 9 volt, measured with my multimeter at 9.2 volts. If I pull out the battery with the 9 volt connected, it does seem to maintain the connection.

On further inspection, the cortex lights briefly flash red before the orange “reconnection” lights appear.

@gzook ,
We were also having similar issues at the Cav Cup tournament yesterday. The day before, everything was fine, but then on the day of the tournament, we were losing connection, having battery problems… you name it. The weird thing is, is that we just got a brand new cortex and vexnets several days before which are all up to date. I did notice several teams having problems as well. It could have possibly been a problem with the field (later in the tournament I saw the cords being replaced on the Boeing field).

This is completely irrelevant to the problem but I just realised you and I are in the exact same area. We were the reason they replaced those cables, I was the guy wearing the hat and the ugly green jersey.

Gotcha. I guess I just assumed you were having the problem at the tournament. If you haven’t already, try the troubleshooting guide and the cortex and joystick users guide.

I guess I never noticed you guys at the match when they replaced the cables :slight_smile:

Oh whoops, I meant my comment was irrelevant. While I’m sure the competition control caused issues for some, we have this problem everywhere.


Here are VEX LED diagnostic codes from the appendix-2:

According to them fast yellow blinking would indicate a disabled mode. Something is going on that triggers robot entering into disabled mode (or some other undocumented mode).

So you need to rule out bad VEXNet keys and joystick connectors and/or firmware.

I would start by updating VEXNet keys and Joystick firmware, and if problem reapperas borrowing joystick and keys from another team for testing.