Overheating is the most common reason why your radio might start to smell like it's burning. If you've been using your radio for a while and it starts to emit this scent, it's likely that the components inside are starting to overheat. This can happen for a number of reasons, such as if the radio is placed in an enclosed space or if it's been turned up too loud. In either case, you'll want to turn off the radio and allow it to cool down before using it again.
In some cases, the burning smell might be coming from the power cord of your radio instead of the actual unit itself. If this is the case, then there could be an issue with the way that the cord is plugged into an outlet or with the outlet itself. If you're unsure, unplugging the cord and plugging it back in may help reset things so that they're working properly again. If not, you may need to get a new power cord for your radio.
Ultimately, any time your radio starts to smell like it's burning, you'll want to take action to figure out what's causing the problem. Overheating is usually the root cause but addressing other potential issues can help prevent further damage to yourradio (and potentially yourself).