La-e791p Rev 2.0 Schematic Diagram

The charging IC (often an Intersil/Renesas or Texas Instruments chip) must output an ACDRV (AC Drive) voltage to turn on these isolation MOSFETs. If VIN stalls at the first MOSFET, the charging IC or the input current sensing resistor is likely faulty. Step 2: Always-On Power Rails ( +3.3V_ALW & +5V_ALW )

The EC’s +3.3V_RTC backup circuit now includes a larger supercapacitor (0.22F vs 0.1F in Rev 1.0), allowing RTC retention for up to 72 hours instead of 24.

Fault 2: Laptop Turns On but No Display (Caps Lock Doesn't Respond)

The VCC_CORE for the Intel Kaby Lake-R is complex. Look for a multi-phase controller like the . La-e791p Rev 2.0 Schematic Diagram

The standby IC creates the +3VALW and +5VALW voltages. Without these, the power button will do nothing. The schematic will show you which "Enable" pins are required from the EC to trigger these rails. BIOS and EC Firmware

PM_RSMRST# (SIO pin 128) → PWRBTN# (SIO pin 64) → PM_PWRBTN# to CPU.

: Features rails such as +1.8V_PRIM and +1.2V_VDDQ (RAM power). The charging IC (often an Intersil/Renesas or Texas

: A commercial source for the full boardview and circuit diagrams.

Compal schematics feature a block diagram on page 2 or 3. Identify the page numbers for the specific sub-circuits you need (e.g., Page 38 for Charging Circuit, Page 45 for Audio).

[Visual Inspection] ➔ [Check Resistance on Main Rails] ➔ [Measure DC-In Voltage] ➔ [Verify 3V/5V Always-On] ➔ [Check EC Signals] Fault 2: Laptop Turns On but No Display

Before you press the power button, the motherboard must generate the standby voltages to power the Embedded Controller (EC) and the power button circuit.

: Includes +3VALW and +5VALW , which must be present for the laptop to trigger power.