Solar Fans

Hello,

I know this isn't directly related to the purpose of this group but hoping to leverage your expertise. We have two solar fans in our attic that are not working correctly. They do not start spinning on their own. If I go up in the attic and spin the fan blades myself it seems to continue running for a while. Ill check again a few hours later and theyre off again. Wondering what issues to try checking?

Google seems to point at a few things but nothing seems to fit exactly what i see happening. Dirty panels, dying motor, bad wiring, etc. Any suggestions on what to look at 9lor how to fix. Thanks!