Lac781p Schematic Top __full__
The Compal LA-C781P is a motherboard primarily found in laptops (e.g., HP 15-af109ur, HP 15-af002ur) and HP Compaq models. Understanding the board revision is critical. The board is often marked with the text "ABL51 LA-C781P Rev: 1.0" silkscreened directly onto the PCB.
By following this structured approach, you can successfully diagnose and repair power-related issues on the LA-C781P. Good luck with your repair journey.
The "schematic top" (or main component side) generally includes the following critical areas:
Check VCC (Pin 20) and ACN/ACP on the BQ-series IC; measure the voltage on the ACDRV line. lac781p schematic top
The board starts with a 19V input from the DC jack.
The VCore PWM controller initializes, delivering dedicated power envelopes to the computing modules of the SoC.
[DC Jack Input] ──> [First/Second MOSFETs] ──> [Main Current Sense Resistor] ──> [3V/5V Standby IC] Step 1: Isolating the DC-In Stage The Compal LA-C781P is a motherboard primarily found
The 3V RTC cell power is active even before the charger is connected.
LA-C781P Motherboard Schematic Overview Compal LA-C781P (often labeled as ) is a common motherboard found in series laptops. It features an AMD Stoney Ridge or similar APU architecture and utilizes the embedded controller. Technical Quick Specs : Compal ABL51 Common Laptop Models : HP 15-af011ur, HP 15-af series Embedded Controller (EC) : ENE KB9022Q Main PWM Controller : Often utilizes the for power rails (e.g., positive 3 cap V cap A cap L cap W cap P positive 5 cap V cap A cap L cap W cap P Troubleshooting Common Issues If you are dealing with a "No Power" (Dead) state, technicians frequently focus on the VIN circuit and the power sequence for the EC. Check the +3VALW rail : Ensure it is reaching pin 15 of the EC (KB9022Q). VIN Circuit
The term "Schematic Top" typically refers to the or Top Overlay of a PCB design file. This layer displays the physical layout of components, tracks, and silkscreen on the primary side of the circuit board. The identifier "LAC781P" likely designates the specific Printed Circuit Board (PCB) model or the primary Integrated Circuit (IC) mounted on the board. Without a specific manufacturer name (e.g., Sony, Samsung, GE, or an industrial automation brand), the exact proprietary schematic cannot be generated in this report. However, the following analysis outlines the probable nature of the component and methodologies for locating the diagram. By following this structured approach, you can successfully
Gate drive for entry MOSFETs; must be higher than VIN (around 24V-25V ) to allow power into the board. Initial Power Sequence (Standby)
Based on similar naming conventions, the LAC781P is most likely one of the following:
A: Usually, yes for major component placements, but minor revisions (e.g., 1A, 2.0) often change resistors or capacitors around the power supply. It is always best to search for the exact Rev number printed on your board.
Detection pin, typically between 2.4V and 3.1V .
The (also known as ABL51) is a motherboard used in HP 15-af series laptops . A "schematic top" generally refers to a technical diagram or board view used by technicians to identify the physical location and electrical connections of components on the upper side of the motherboard. Repair Narrative: The "No Power" Mystery