MSI laptops are notorious for BIOS corruption. The schematic tells you:
Locate the charger IC on the schematic. Note the pinout and measure the voltages on all its pins. The charger IC controls the gate voltages for the input MOSFETs, so any abnormality here will prevent the board from powering up.
If the 3.3V and 5V rails are active but the board refuses to POST (Power-On Self-Test), the SPI Flash memory holding the BIOS code or the EC firmware may be corrupted. ms-16j91 schematic
A schematic tells you how components connect logically, but it does not tell you where they sit physically on the physical MS-16J91 motherboard. Open a matching .CAD , .BRD , or .BDV boardview file alongside your PDF schematic. Clicking a pin in the boardview software will instantly highlight every connected pad, trace, and test point across the entire PCB layout. Step 4: Isolate Shorts with a Bench Power Supply If you find a primary rail shorted to ground (0 Ohms): Set your bench power supply to 1 Volt. Limit the current to 1 Ampere. Inject this safe voltage directly onto the shorted rail.
ENE KB9028G or similar programmable IC, responsible for power sequencing, keyboard matrices, fan control, and battery charging logic. 2. Deciphering the MS-16J9 Power Sequence MSI laptops are notorious for BIOS corruption
If the MSI logo is faintly visible on the LCD screen but the backlight is missing, trace the +19V_BL line on the LCD connector schematic page. A small surface-mount fuse near the connector is likely open.
This is a chart showing the order in which power rails must turn on. If the 3.3V rail is missing, the CPU will never receive power. The charger IC controls the gate voltages for
What have you taken so far on the main coils?
Two SO-DIMM slots. Includes data lines, address lines, and SPD (Serial Presence Detect) connections.
: Typically populated with a 7th Generation Intel Kaby Lake processor (e.g., Intel Core i7-7700HQ or i5-7300HQ ) tied directly to the PCH. The PCH handles lower-speed communications, PCIe lanes, storage interfaces, and the boot sequence.
On the MS-16J91, resistor is a common point of failure. Measure its resistance. It should be approximately 1.8K ohms . If the reading is significantly higher, desolder it from the board and test it again. Replace it if it is out of spec.