Bm5291 Ver 1.3 Schematic ((top)) -

Schematics for the BM5291 Ver 1.3 are often hosted on specialized repair communities. While direct PDF downloads from the manufacturer are rare, you can find them on:

The schematic will point you to a dual PWM regulator chip. You must measure the output inductors (coils) for these rails to ensure the chip is receiving its main feed and outputting clean standby voltages. 3. Embedded Controller (EC) & BIOS Architecture bm5291 ver 1.3 schematic

Based on repair history for the Lenovo S215 platform, several common electrical bottlenecks regularly appear: Probable Cause Component Diagnostic Step Failed Input MOSFET or Shorted Ceramic Capacitor on B+ Rail Schematics for the BM5291 Ver 1