AVH-4100NEX shutting off randomly while driving

[kjdbonez]

I installed an AVH-4100NEX in my Subaru Outback in 2015. Everything was working perfect until the last week or so until it started shutting off randomly while driving. It seems to happen after about 15 minutes and then it will stay off completely until I turn my car off and back on again. I use Android Auto frequently and usually have my phone plugged in for that. I can't recall if all of the shut-downs have happened while phone is plugged in or not. I haven't installed any new electronics on the car for almost 5 years, and I haven't been in any accidents or on rough terrain, so can't imagine anything got jostled out of place. Although its warmed up quite a bit here recently it doesn't seem to occur if/when the A/C is on necessarily. I found a couple similar posts regarding Pioneer radios randomly shutting off or rebooting. There were suggestions that it may be related to firmware, and I did update the firmware to the latest version sometime last year. Mine doesn't reboot - the screen just goes black and the buttons do too and if my phone is plugged into the USB port it also stops charging. I know its kind of "old" now, but I was hoping not to have to replace the stereo since my car is also getting kind of "old." Any thoughts or ideas on how to troubleshoot this?