I can help mentioned, or I can draft a social media teaser to go along with this post.
Check the DC input or AC rectification stage. The BM5291 often utilizes a protection diode or a resettable fuse (PTC). If the board is completely dead, start here. The schematic will show you exactly where the test points (TP) for the input voltage are located. 2. The PWM Controller / Logic Core
Utilizes a bridge rectifier configuration alongside high-voltage smoothing capacitors to establish a stable high-voltage DC bus. bm5291 ver 13 schematic verified
A large SMD inductor and high-speed diode boost the voltage.
Large collections of verified boardviews and schematics are often hosted on platforms like DisplayMonk or specialist forums. I can help mentioned, or I can draft
Ensure the SPI Flash ROM (BIOS) chip has clean +3VS power and data communication via a logic analyzer or oscilloscope. 3. Resolving Intermittent Shorts on Secondary Rails
Any you have gathered from pins 12, 18, or 20. If the board is completely dead, start here
Before applying power, place the PCB under a microscope or magnifying glass. Look closely for: Discoloration or bubbling on the surface of the main PMIC.
BM5291 Version 13 schematic is widely recognized in the laptop repair community as a "verified" or "100% working" resource for troubleshooting specific motherboard issues, typically associated with board series like