You probably want to verify its faulty. In my case it was hot to the touch and the PM5 was drawing a massive 800mA so it had an internal short.
I would look at what sort of current its drawing using a 3Vdc supply as it tells you a lot as to whether the micro is working. Should be about 35mA from memory and in shutdown it drops to like 0.060mA or about the same level as the old PM2. Sometimes the Micro just dies and you will see a low current draw and nothing happening on screen.
The part number is something like AS1337 or AS1525 for the regulator. There is a top mark code on the chip. Both parts are possibly interchangeable.
https://www.digikey.com/en/htmldatashee ... 0/1/as1337