No power, no display, power-on-no-display (POND), charging failure. 2. Key Power Rails in the Schematic
Try searching for:
Measure the voltage at the DC jack ( PJDC1 ) to ensure 19.5V enters the board. Check pins 1-3 (Source) and pin 4 (Gate) of PQ24 and PQ25 .
For detailed repair work, you need the and Boardview file . bdl51 lad711p rev 30 schematic work
Once you have the schematic in hand, you can begin the systematic work of diagnosing your non-functional laptop. Based on community reports, here are the most common points of failure on the BDL51 LA-D711P board.
The Lad711p Rev 30 board functions as the central processing unit for the BDL51 unit. Based on standard industrial control architectures of this class, the schematic can be segmented into four primary subsystems:
This is the primary 19V rail. If this is missing or shorted to ground, the laptop will appear completely dead. Check pins 1-3 (Source) and pin 4 (Gate) of PQ24 and PQ25
, as they share highly similar architecture and component positioning. Component Identification
Because an exact Rev 3.0 schematic is rarely available, repair experts recommend the following strategies: Cross-Reference Similar Boards : Use the schematic for the
Check for the internal Linear Regulator outputs ( +3VLP or VREG3 and VREG5 ). These LDO outputs must be present to boot the EC chip before the main switching coils turn on. Step 4: Investigating a "No Display" Condition Based on community reports, here are the most
The BDL51 LA-D711P Rev 30 is a widely utilized Compal motherboard found in several generations of Hewlett-Packard (HP) laptops, most notably the HP 15-AY and 15-BA series. When these laptops fail to power on, experience short circuits, or suffer from charging anomalies, having access to the schematic diagram is essential for component-level repair.
To help narrow down your diagnostics on this specific board, let me know:
Voltage spikes from faulty aftermarket chargers often destroy the first or second isolation MOSFETs. If PQ24 or PQ25 gate voltages fail to rise (which should be roughly 25V to drive N-channel gates open), the 19.5V rail stops at the source of the first MOSFET. Corrupted BIOS / EC Firmware
Powers the RAM slots.