Celestine S20 troubleshooting

First off, I'm pretty handy & have some electronics experience (mostly 3d printers), just new to working on a speaker. The only place local to me that says the can work on it says they're backlogged at least 3 months, & a rep at a local A/V store recommended I try asking here.

I have a Celestion S20 powered subwoofer on my home theater. I've had it at least 15 years w/ no trouble. This week, it started making a buzzing noise & then very quickly stopped making any sound at all. The light on the rear went from green to red. A Google search told me this means it's in safe mode but not much else. I'm having trouble finding the guide for this speaker, I've found guides for ones that are close, or say S20 but don't look like my model

Is this something I can troubleshoot myself or should I scrap it & get another sub? Can anyone help me fix this?