La-7912p Rev 1.0 Boardview !!top!! -

: Keep your schematic PDF open on one monitor and your boardview tool open on another. When you encounter an ambiguous component identifier like PR27 in the schematic, typing it into the boardview filter instantly highlights its real physical footprint.

While a standard schematic shows you the theoretical electrical connections (how components talk to each other conceptually), a shows you the physical layout of the board. la-7912p rev 1.0 boardview

The LA-7912p board suffers from a few notorious engineering vulnerabilities. Here is how to use the boardview to diagnose them. 1. No Power / Dead Board (Short on B+ Rail) : Keep your schematic PDF open on one

| Symptom | Suspected Component(s) | Notes | | :--- | :--- | :--- | | | PU4 (BQ25A) Battery Charger IC, PQ9 & PQ10 MOSFETs | These are frequently reported as damaged. A common fault is "no DC-in" or the battery not being detected. Replacing these is a typical repair step. | | Device Powers Off at ~98% Battery | Faulty resistor divider on ACDET pin of PU4 | A less common but interesting issue where the charger disconnects as the battery nears full capacity. | | No CPU / GPU Power | PU20 (KB9012QF A3) Embedded Controller, ISL95836 VRM | The EC might not be sending the SYSON (system on) signal to turn on the voltage regulators. | | PCH Overheating | PCH (Platform Controller Hub), Corrupted BIOS | Shorts or damage to the HM76 chipset can cause it to overheat. | | Liquid Damage | Corroded Traces near LVDS Connector | Liquid near the LVDS connector can short the backlight circuit and blow the backlight fuse. | | Random Shutdowns | GPU Power Phase (VGA_CORE) | The dedicated Nvidia GPU draws large amounts of current. Faulty VRM components can cause shutdowns under load. | The LA-7912p board suffers from a few notorious

Trace "nets" (connections) to see where a signal goes if a copper trace is blown or corroded.

: Displays the exact X/Y coordinates of every pin, pad, test point, and trace on both the top (Side A) and bottom (Side B) of the board.

| Net Name | Description | |----------|-------------| | +VIN | DC input (19V) | | B+ | Main battery voltage | | +3VALW | Always-on 3.3V | | +5VALW | Always-on 5V | | PM_SLP_S4# | Sleep state S4 (PCH to EC) | | PM_SLP_S3# | Sleep state S3 (PCH to EC) | | VR_ON | CPU VR enable | | EC_RSMRST# | EC reset | | DDR_VTT | DDR termination voltage (0.675V) | | SUSP# | Suspend signal | | AC_IN | AC adapter detect (from BQ24737) |