You can use a Kill-A-Watt meter to see what your voltage is during play, while heater kicks on, etc. A multimeter with logging might be helpful.
I'd be surprised if 3-4 volt drop at the wall caused it but that system is really picky about the 5v.
If 5v mpu dropping is the cause you can use a Kahr board: https://www.kahr.us/daughterboard.html
Creates a new source for the 5v that doesn't have the same design deficiency of the original.