I've tried all of that already. Fan speeds look ok because I can see the fan ramping up when it's overheating and then ramping down when the miner auto reboots.
I reset it to default and reinstalled the latest firmware too. It was running fine for last 3 months. In fact, I opened to clean it because past few days it was running into 80s. Now I frikking regret opening it. Just my luck! Wondering if Bitmain will help me troubleshoot it because it's no longer under warranty and I don't want to spend money to fix it. lol!