We were just prepping our robot for an outreach event at our school, when we realized that the radio seems to be dead. We have the power wired correctly, and used it all of last season with no issues, but now none of the lights are turning on. What should we do to diagnose the radio for problems, and how can they be fixed?
First thing I would do would be to take a multimeter and some spare wire and check to make sure you’re actually getting 12V/2A out of your VRM. If you’re not getting anything, you found your problem. Otherwise, put your black multimeter lead on the pin inside the barrel connector, and your red one on the outside. (You might get a negative number. I forget which is ground :)). If you get nothing here, but you got something from the VRM, your problem is the cable. After that, if all of this works and your radio still doesn’t get power, your radio is probably dead.
Center positive is common, meaning the center of the barrel plug is positive and the shell/outside is negative/ground. Make sure not to short it with the multimeter.
Check that your VRM is getting power.
An often overlooked fault is the fuses for the RoboRio and VRM power rails, Ive had instances where one was knocked loose, so it looked fine, but once I touched it it was obvious, this is only an issue if you have no power going into the VRM of course
The VRM had power, it’s status lights were green. I will check the cable tomorrow at our meeting.