The cortex/joystick will disconnect seemingly at random. After disconnecting, it will take anywhere from 10 to 30 seconds to reconnect, before disconnecting again after 5 to 10 seconds. Most of the time, it does not happen when we are plugged into a competition switch. Has anyone else had this problem or found a fix?
Yes. Switch to v5 
Seriously though, it’s usually a firmware or hardware issue. If it’s firmware, simply hard-updating the firmware will solve the problem. Be sure to use the manual firmware update however. I have no idea why this solves the problem but it sometimes does.
If not, your vex keys might be damaged or your controller batteries might be low. These things are easy enough to test by experimenting with another team’s keys or recharging the controller batteries.
Chances are there’s nothing in the code you can change to fix this, but try running a very simple program. If the simple program runs with no DCs but your normal competition program doesn’t, the code is the issue.
Good luck!
this problem may be because of your battery/s. the problems with the battery may be a few things.
- the white part of the battery wiggles
- the wires are loose
- the cortex plugin is loose
problms - a problem with the white connecting piece
- the part where the wire goes to the battery’s
- or the cortex itself where the battery plugs in
fixes - there are no fixes for this get another battery
- pull the blue cover off the top of the battery with a box cutter then solder the wires back to the battery’s
- there are no fixes for this get another cortex
if these don’t fix it then it is the keys that need to be replaced and/or the cortex vexnet is broken.
James Chase
Do you have a 9V backup battery plugged into the Cortex? If yes, when was the last time you checked its charge level? The backup battery keeps the Cortex from resetting when the motors demand a lot of current from the main battery. If it is missing or dead, the Cortex can momentarily lose power, reset, and have to reseek a VEXnet connection.
This is, of course, just one of many possibilities, but worth checking.
Something I have found is that if The cortex is surrounded by metal it can have issues with connection.
In the third situation where the cortex plug in is loose my team has found that if you take a broken link of chain and shove it in right next to the battery it will keep a secure connection with the cortex.
This is what I’ve seen. And what I would try if I have the problem.
And, @Anomaly , not all of us are lucky enough to have V5. Some of it ships in 8 months.
switch and mich match vex net keys we had the same problem and had to switch about 6 diffrant vexnet keys and one pair that we have works fine know
if you haven’t already, try adding a backup 9v battery.
In a case where you are having constant disconnects, it is either a remote, CORTEX battery, Firmware, or VEXnet problem most likely. Get used to trouble shooting, it’s really helpful. In order to make sure the troubleshoot is fixed, to not just having the robot stop moving because it lost power from the main battery although the CORTEX still being on and powered, I suggest troubleshooting without a 9V backup battery.
Troubleshooting #1
First and foremost, reinstall all of the firmware in the CORTEX, Controller, as well as try updating the VEXNet key with the VEXNet key utility. You will have to re-download the code you built for the robot if you are reinstalling the firmware. If updating and reinstalling the firmware did not solve the disconnect problems, move on.
Troubleshooting #2
First, turn on the controller and, while holding, try lightly hitting it. If the remote restarts, then it’s a circuit problem, you haven’t taken the precautions of screwing the battery compartment in, or one of the springs that hold the batteries in are weak. If the controller still restarts after it gets hit after checking the battery compartment, try replacing the VEXNet key. If replacing the VEXNet key doesn’t solve the problem of the controller restarts, contact VEX. If the controller doesn’t restart after being hit lightly a couple of times, move on.
Troubleshooting #3
Turn on your robot and connect a speaker to the VEX CORTEX. If you don’t have a speaker, keep a keen eye on the lights of the CORTEX. Lightly drop the robot from around 1-2 inches from the foam and see/hear if the CORTEX restarts. If the CORTEX restarts, its most likely a battery connection or VEXNet key problem. Make sure that you are using battery extension cables to make sure you are not damaging the CORTEX battery port over constant plugging and unplugging. Sometimes, there are bad battery extension cables as well. If necessary, try replacing the battery extension cables with a new one and see how it goes. There are so many reasons for a CORTEX to disconnect. I can come up with more solutions if necessary.
It’s usually the battery not connecting well for me. The 9V, for the most part, fixes this. I’ve heard of teams using a piece of chain link to shove into the plug-in to hold the loose battery to one side, where it makes the circuit connection. Otherwise, Connor’s list is pretty good.