Acer Extensa 4620 4220 (Compal LA-3551P) Schematic & Boardview Download + Chip-Level Diagnostic Guide

The Acer Extensa 4620 and 4220 series, built on the robust Compal LA-3551P (Columbia) motherboard architecture, represents the pinnacle of the Intel Santa Rosa platform era. Featuring the Intel GM965/GL960 chipset paired with the ICH8-M Southbridge, these machines are common visitors to repair benches due to aging electrolytic capacitors and power sequencing failures. As a senior engineer, I've seen these boards survive over a decade, but they require precise voltage injection and signal tracing to recover from 'No Power' or 'Random Shutdown' states.

Board Architecture & Technical Specifications

Feature	Specification / Component
Motherboard Model / ODM Part Number	Compal LA-3551P (ICL50/Columbia)
Target Laptop Series	Acer Extensa 4620, 4620Z, 4220
Chipset / CPU Architecture	Intel Socket P (Core 2 Duo / Pentium Dual-Core) + ICH8-M
Super I/O (EC/KBC) Controller	ENE KB926QF-B1
Key Voltage Rails & Coils	+3VALW (PL6), +5VALW (PL7), +1.8VP (PL9), +VCC_CORE (PL10/PL13)

Real-World Motherboard Diagnostic Procedures

1) Input Power Stage & DC-IN Protection Circuit

On the LA-3551P, the VIN rail (+19VB) is governed by the ISL6251 (PU1) charging IC. If the laptop is dead with 0.00A draw, first measure the voltage at PR4 (the main current sense resistor). If 19V is missing here, check the gates of the protection MOSFETs PQ1 and PQ2. The ISL6251 must output a high ACPRN signal and the PACIN signal must reach the EC to allow the system to switch from battery to adapter power. A common failure is a leaky ceramic capacitor on the B+ rail causing the input FETs to stay closed.

2) Standby Rail Generation & RTC Reset

The +3VALW and +5VALW rails are generated by PU4 (TPS51120). Before pressing the power button, verify 3.3V on PL6 and 5V on PL7. If these are absent, check the LDO outputs: VREG3 (Pin 21) and VREG5 (Pin 19). For legacy Acer boards like this, the RTC battery (CR2032) is critical; if it drops below 2.5V, the RTCRST# signal to the Southbridge may fail, preventing the EC from initiating the power-on sequence. Always check the 32.768kHz crystal (Y2) for oscillation if standby rails are present but the board won't trigger.

3) Power-On Sequence & The NEC/TOKIN Factor

When the power button is pressed, the ENE KB926 pulls KBC_PWRBTN# low and releases PM_SLP_S3# and PM_SLP_S4#. A notorious issue with this era of Acer laptops is the NEC/TOKIN OE128 (or OE907) proadlizer capacitor located directly under the CPU socket. This capacitor filters the +VCC_CORE rail. Over time, its ESR increases, leading to thermal shutdowns or the laptop failing to boot when the AC adapter is plugged in (but working on battery). Replacing this single component with four 330uF tantalum capacitors (Tantalum Polymer) is a standard "Gold Level" repair for this model.

Download Schematic & Boardview Files

📥 Download ACER EXTENSA 4620-4220 Schematic / Boardview

Direct download link. Verified Compal LA-3551P schematic archive.

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

Acer Aspire 5920 ZD1 (Compal LA-3551P) Schematic & Boardview Download + Chip-Level Diagnostic Guide

The Acer Aspire 5920, famously known for its "Gemstone" design, is a classic performance machine based on the Intel Santa Rosa platform. At its heart lies the Compal LA-3551P (ZD1) motherboard. While this model was a powerhouse in its era, it is notorious among repair engineers for specific failure points, including the MXM graphics card failures and the infamous NEC/TOKIN capacitor degradation. In this guide, we provide the technical blueprints and a deep-dive diagnostic framework for restoring this legacy hardware.

Board Architecture & Technical Specifications

Feature	Specification / Component
Motherboard Model / ODM	Compal LA-3551P (ICW50) / ZD1
Chipset Architecture	Intel PM965 (Northbridge) + ICH8M (Southbridge)
Super I/O (EC/KBC)	ENE KB926QF B1
Charging Controller	Intersil ISL6251 (PU1)
Main Voltage Rails	+3VALW (PL5), +5VALW (PL4), +1.8V (PL10), +VCC_CORE (PL11)

Real-World Motherboard Diagnostic Procedures

1. DC-IN Isolation & Charging Logic Analysis

On the Compal LA-3551P, the input power stage begins at the DC jack (JDC1) and passes through the dual P-Channel MOSFET protection circuit. If the board is completely dead, start by measuring +19VB at PR3 (Current Sense Resistor). If 19V is missing, check PU1 (ISL6251). Ensure DCIN (Pin 24) is receiving power and ACSET (Pin 20) is approximately 1.2V. If PACIN is not high, the EC will not enable the system power. Inspect PQ1 and PQ2 for source-to-drain shorts which are common if a generic universal charger was used.

2. Standby Rail Generation & Resistance Norms

The 3.3V and 5V Always-On rails are generated by PU4 (MAX8744). Unlike modern boards, this era uses larger tantalum and electrolytic caps that can leak. Measure the resistance to ground on PL5 (+3VALW) and PL4 (+5VALW). A reading below 100 ohms usually indicates a shorted Southbridge (ICH8M) or a punctured ENE KB926QF. If the rails are missing but no short is present, verify SHDN# (Pin 20) is pulled high. If the laptop shuts down immediately after a few seconds, check the +1.8V (PL10) rail which powers the DDR2 memory; a failure in PU10 (ISL6227) is a frequent culprit.

3. Power-On Sequence & The NEC/TOKIN Fix

The LA-3551P follows a standard Compal power-up sequence: EC_ON triggers the ALW rails, followed by MAINON and SUSP#. If the board triggers but displays no video, or crashes under load, the primary suspect is the NEC/TOKIN OE128 capacitor (located directly under the CPU socket). This capacitor filters +VCC_CORE. Over time, its ESR increases, causing ripple that crashes the Core 2 Duo CPU. The professional fix involves removing the NEC/TOKIN and replacing it with 4x 330uF (6.3V) Tantalum polymer capacitors to ensure stable VCore delivery.

Download Schematic & Boardview Files

📥 Download ACER-ASPIRE5920-ZD1 Schematic / Boardview

Direct download link. Verified schematic / boardview archive for LA-3551P.

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

Acer Aspire 5920 5920G (Compal LA-3551P) Schematic & Boardview Download + Chip-Level Diagnostic Guide

The Acer Aspire 5920 and 5920G, part of the iconic "Gemstone" design era, are built upon the robust Compal LA-3551P (ZD1) motherboard architecture. This platform utilizes the Intel Santa Rosa chipset (PM965/GM965) paired with the ICH8-M Southbridge. As a legacy powerhouse, it features an MXM-II discrete graphics slot and the Intel Core 2 Duo processor. For the modern bench technician, repairing these boards requires a deep understanding of the older Compal power sequencing and the specific failure points inherent to the 65nm/90nm semiconductor era, including the notorious NEC/TOKIN capacitor issues.

Board Architecture & Technical Specifications

Feature	Specification
Motherboard Model / ODM Part Number	Compal LA-3551P (ZD1)
Target Laptop Series / Form Factor	Acer Aspire 5920 / 5920G (15.4" Multimedia)
Chipset / CPU Architecture	Intel PM965 + ICH8-M / Socket P (Merom/Penryn)
Super I/O (EC/KBC) Controller	ENE KB926QF B1
Key Voltage Rails & Switching Coils	+3VALW (PL7), +5VALW (PL6), +1.8V (PL10), +VCC_CORE (PL11, PL12)

Real-World Motherboard Diagnostic Procedures

1) Input Power Stage & DC-IN Protection Circuit

On the LA-3551P, the VIN rail (+19VB) is managed by the ISL6251 (PU1) charging IC. If the laptop is completely dead with no lights, first check for 19V at the drain of PQ1 and PQ2. Unlike modern systems, these are often P-Channel MOSFETs. Ensure the gate voltage is pulled low (~8V-9V) to allow conduction. A common failure point is the current sense resistor PR13; if it is open, the system will not detect the adapter. Verify ACIN (Pin 23) on PU1; it must be approximately 3.2V for the EC (ENE KB926) to initiate the power-on sequence.

2) Standby Rails & NEC/TOKIN Stability Issues

The +3VALW and +5VALW rails are generated by the ISL6236 (PU4) PWM controller. Check PL7 for 3.3V and PL6 for 5V. If these are missing, check the LDO output (VREG3/VREG5) on pins 1 and 15. A unique issue with the Aspire 5920G is the NEC/TOKIN OE128 capacitor located directly under the CPU socket. This high-capacitance decoupling filter degrades over time, leading to sudden restarts or "no power on AC" symptoms. As a senior technician, I recommend replacing this with four 330uF Tantalum capacitors (ESR < 10mΩ) to restore VCC_CORE stability.

3) Power-On Sequence & Signal State Tracking

The ENE KB926 EC must release EC_ON to enable the secondary rails. For a "No Display" fault on the 5920G, focus on the MXM-II slot power. The discrete GPU (often an 8600M GT) is prone to BGA failure due to thermal stress. Verify +VCC_GFX at the MXM connector. If the board powers on but hangs at 0.6A-0.8A consumption, check the PM_SLP_S3# and SYSON signals. If these are present but there is no VCC_CORE, inspect the ISL6262 (PU11) controller. Always perform a BIOS/ME clean dump on the 1MB SPI Flash (U27) if the power sequence completes but no POST occurs.

Download Schematic & Boardview Files

📥 Download ASPIRE 5920,5920G Schematic / Boardview

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