I’ve been experiencing issues with some T-Beams not booting up anymore. Symptoms were either not even powering up or being stuck in a boot loop before the firmware splash screen.
Having read several posts complaining about fried AXP192 and being myself too lazy to attempt desoldering the chip to replace it, I’ve instead tried a poor man’s reflow by heating up the whereabouts of the AX192 with a fairly small heat gun (300 W) for a minute or two. Success!
I’d encourage those who suspect a dead AXP192 to try this method, but please heat-shield or even better remove the display beforehand! Don’t ask me how I know…
Heatgun works but you always run the risk of blowing away the little surface mount resistors and capacitors.
Another method is the oven at 220C for a couple minutes, but that method reflows everything on the board and you’ll also have to remove the battery holder.
Personally I would use a fine tip soldering iron, lots of water soluble flux and a good set of eyes.