Acer Aspire 4930 Compal LA-4201P Schematic & Boardview Download + Chip-Level Diagnostic Guide

The Acer Aspire 4930, built on the robust Compal LA-4201P (JAL90) motherboard architecture, represents the pinnacle of the Intel Centrino 2 (Montevina) era. Featuring the Intel PM45/GM45 chipset paired with the ICH9M Southbridge, this board is a classic example of Compal's multi-rail power sequencing. For the chip-level technician, this board is often seen in the shop for thermal-related GPU failures or the notorious NEC/TOKIN capacitor degradation that plagues this generation of Acer laptops.

Board Architecture & Technical Specifications

Component Type	Specification / Part Number
Motherboard Model / ODM Part Number	Compal LA-4201P (JAL90)
Target Laptop Series	Acer Aspire 4930 / 4930G
Chipset / CPU Architecture	Intel Penryn (Socket P) + PM45/GM45 + ICH9M
Super I/O (EC/KBC) Controller	ENE KB926QF D3
Key Voltage Rails & Switching Coils	+3VALW (PL4), +5VALW (PL5), +1.8V_DDR (PL6), +VCC_CORE (PL10/PL11)

Real-World Motherboard Diagnostic Procedures

1) Input Power Stage & DC-IN Protection Circuit

On the LA-4201P, the 19V input rail (+19VB) is managed by the ISL6251 (PU1) charging IC. If the board is completely dead, first measure the voltage at the current sense resistor PR3. If you see 0V, inspect the two P-Channel MOSFETs PQ1 and PQ2.

• Check PU1 Pin 24 (DCIN) for 19V and Pin 23 (ACIN) which should be around 3.2V.
• If ACIN is present but the gates of PQ1/PQ2 are high (19V), the charging IC is not pulling the gates low to enable the rail. This is often caused by a short circuit on the main B+ line or a faulty PU1.

2) Standby Rail Generation & S5 State Troubleshooting

The +3VALW and +5VALW rails are generated by PU4 (TPS51125). This IC must produce VREG3 (Pin 8) and VREG5 (Pin 17) immediately upon connecting the adapter.

• Measure resistance to ground on PL4 (+3VALW) and PL5 (+5VALW). A low resistance on PL4 often points to a shorted ENE KB926QF EC or a shorted PCH.
• The EC_ON signal from the KBC must reach PU4 to enable the switching output for the coils. If the power button is pressed and +3VALW/+5VALW are present but the laptop doesn't trigger, check RSMRST# at the EC (Pin 100) to ensure the SIO is signaling the Southbridge to wake up.

3) VCC_CORE Stability & The NEC/TOKIN Issue

A frequent failure on the Acer 4930 is the laptop shutting down under load or failing to boot despite all rails being present. This is almost exclusively due to the NEC/TOKIN OE128 decoupling capacitor located directly under the CPU socket.

• Use an oscilloscope to check for excessive ripple on +VCC_CORE at PL10/PL11. If the ripple exceeds 50-100mV, the NEC/TOKIN has failed.
• Repair Tip: Replace the single NEC/TOKIN with four 330uF Tantalum capacitors (25V or higher) to restore stability. Additionally, if the board has no VCORE, check PU10 (ISL6262) for the VR_ON signal coming from the EC.

Download Schematic & Boardview Files

📥 Download ACER ASPIRE 4930 - COMPAL LA-4201P - SC Schematic / Boardview

Direct download link. Verified schematic / boardview archive for professional repair.

Professional Repair Assistance

Explore our technician resources:

• 🛠️ Diagnose No-Power & Short-Circuit faults step-by-step: Interactive Laptop Diagnostic Lab
• 🛒 Original Replacement Motherboards & IC Components: Official Spare Parts Mega Store