I’m trying to repair a Lucky Miner LV06 Bitcoin miner that was given to me.
It looks like someone plugged 12 V into the 5 V rail and fried the three small adjustable regulators.
Each regulator is a SOT-23-5 package, all marked “BFCV.” I can’t find any datasheet or reference to that code. The regulators appear to generate 3.3 V (for ESP32), 1.8 V, and ~0.8 V (for the BM1366 ASICs), set by resistor dividers?.
From tracing the PCB:
Pin 1 (red) → 5 V in
Pin 2 > GND
Pin 3 (yellow) > output ...