Use this forum to chat about hardware specific topics for the ESP8266 (peripherals, memory, clocks, JTAG, programming)

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By Ray Marshall
#94854 I have used some WEMOS D1 mini pro clones where the 3.3V voltage regulator is very flakey.
Anything above 4.5V supply and the regulator shuts down.
There is a diode between the USB 5V and the WEMOS 5V so normally if USB is sourcing 5V then the voltage regulator only see maybe 4.4V and it all works.
But if your USB port on your PC is outputting 5.1V or more, the regulator can collapse.

Easy check is to look at the 3.3V pin on the board.

If this is the problem, you could try a different USB port. Maybe a different PC or test it with a separate power supply.