Robot losing connection

VEX V5 Technical Support UNOFFICIAL Tech Support
1

Ok can anyone tell me a reason other than the basics a robot continually lose connection I think we are a fair experienced team and I’ve tried ever build and programming thing ik to fix this problem but

I really want to fix it before mt competition next week

EDIT: we changed to a new brain and are still experiencing the disconnect

2

I’ve found that some cortices disconnect with the slightest touch of the connection with the battery.
If you use a battery extension cable and zap strap it tightly to the cortex, that always solves the problem.

I haven’t experienced this myself, but I’ve been told that some vex net keys start to lose their ability to stay connected after a few years.

3

I can confirm this works really well!
Another alternative issue could be the pins in the battery wire coming loose. Our team has this issue so what we have done is permanently ziptied a battery extension wire to the battery wire itself.

4

3 common issues:

Mounting your brain/having your VEXnet keys over a stash/pile of aluminum or steel

  1. The cortex ports are broken (including the 2 battery ports; 7.2V and 9V)

  2. Your 7.2V battery’s wire might be cut

5

Thank you for all these suggestions but we already tried those

6

On the connection between the battery and cortex… I have experience in fixing this. First the battery extensions work great! But the connector in the cortex is a female connector and gets expanded over time. There is a tiny cut or slit in the metal connector tubes. You must go in with something like a needle or tiny tool and compress the tubes so that the battery pin has a better connection. I hope this makes sense.
It has happened a lot over the years.

7

Black VEXnet keys or white ones?

8

We’re having the same problem with our robot. It’s only 1 year old and hasn’t been taken apart a bunch, so this is perplexing. I have another team with a robot that’s over 5 years old and has none of these issues. I’ve tested the connector on the battery to determine if anything is amiss there and it seems to be just fine - even with excessive movement of the cables. I’ll attempt to do as n5vei suggested above and report back, but this is a bit annoying as it’s cutting down on true robot build and drive time. Rick Tyler -this is happening with the white keys on our robot.

9

@Rick TYler these are happening with white keys

10

Oh my gosh this has been happening to so many users! I have many different theories but you may or may not agree with me. I have a few questions before answering anything:

  1. Once during that time, have you tried plugging a battery or the battery extension into the CORTEX, you see that it’s not wanting to plug in, so you broot force the battery or battery extension into the plug?

  2. Does your robot seem to have the same issue if you were to be using black VEXnet keys?

  3. Did you try plugging the 2.0 key into the CORTEX, then putting tape firmly and snug onto it to remove movement of the 2.0 key?

  4. Do you have your backup battery on your robot, and fully charged?

  5. Have you tried switching keys with another robot, and yet it does the same thing?

  6. Have you tried replacing your robot batteries?

11

1815 Delta II:

  1. Haven’t brute-forced the connector at all. Always cognizant of the fact that these connectors are crappy as I have another team with an older robot.
  2. We don’t have any black vex net keys as this robot is only 1 year old.
  3. We don’t have any movement of the keys in either the robot or the controller. However, I’ll give this a shot.
  4. No backup battery. I’ll try this also.
  5. Haven’t tried swapping with another robot, but I will.
  6. Again, I’ll try this when I get a spare from the other team.

All that said above, this appears to be a connection problem that needs to be solved by Vex. We had this issue a few times last year (brand new robot) and it seems like poor design has led to this issue and needs to be addressed.

Thanks again for the tips on things to try

12

You’re welcome :slight_smile:
If changing the CORTEX and you’re having the same issues, then try replacing the remote batteries, the same thing happened today with our robot losing connection while lifting, and by replacing our batteries, it fixed almost every issue we were facing…

13

It was an 4 wire extender for our integrated motor encoder that caused the problem -.-