Welcome back to the workbench. Today, we are deep-diving into the Acer TravelMate 4260, built on the venerable Compal LA-2921P (NAY00) motherboard architecture. This platform belongs to the Intel Napa generation, featuring the Intel 945 chipset paired with Core 2 Duo (Merom) processors. While these machines are legacy, they are built like tanks, and common failures usually involve the ageing power rail capacitors, DC-IN MOSFET breakdowns, or the dreaded Southbridge (ICH7-M) thermal stress issues.
Board Architecture & Technical Specifications
| Feature | Specification |
|---|---|
| Motherboard Model / ODM Part Number | Compal LA-2921P (NAY00) Rev 4.0 |
| Target Laptop Series / Form Factor | Acer TravelMate 4260 / 4230 / 4670 Series |
| Chipset / CPU Architecture | Intel 945PM/GM Northbridge + ICH7-M Southbridge |
| Super I/O (EC/KBC) Controller | ENE KB910QF C1 |
| Key Voltage Rails & Switching Coils | +3VALW (PL7), +5VALW (PL6), +1.8VP (PL9), +VCC_CORE (PL12/PL13) |
Real-World Motherboard Diagnostic Procedures
1) Input Power Stage & Charging Logic Analysis
On the LA-2921P, the primary power rail +19VB is controlled by the ISL6251 Charging IC (PU1). If the laptop won't turn on and has 0A draw on the DC Power Supply, check the gate voltage of the protection MOSFETs PQ1 and PQ2 (SI4407). The ISL6251 must output ACSET (Pin 20) correctly for the IC to drive the ACPRN signal. A common fault is the current sense resistor PR3 (0.01 Ohm) drifting in value or the ceramic decoupling capacitors on the VIN line shorting to ground, preventing the main system rail from populating.
2) Standby Supply Rail Verification (+3VALW / +5VALW)
This board utilizes the MAX8734A (PU4) to generate the Always-On rails. Before pressing the power button, you must verify +3VALW at PL7 and +5VALW at PL6. If these rails are missing, check the ON3 and ON5 enable signals coming from the ENE KB910QF. In legacy Compal boards of this era, the electrolytic filtering capacitors (PC54, PC58) often dry out, leading to ripple noise that causes the EC to reset or fail to initialize. Resistance-to-ground on PL7 should be >300 Ohms; if it is lower, the ICH7-M Southbridge or the EC itself may be partially shorted.
3) Power-On Sequence & Signal State Tracking
If the standby rails are present but the board fails to trigger, monitor the MAINPWON signal. The sequence follows: EC receives ON/OFFBTN#, then releases EC_RSMRST# to the ICH7-M. The Southbridge should respond by pulling PM_SLP_S3# and PM_SLP_S5# high. If the board pulses on and then off, check the +VCC_CORE buck converter (ISL6262 - PU11). On this specific 945-chipset platform, the Northbridge (945GM) often suffers from solder fatigue; a diagnostic reflow of the BGA can confirm if the lack of PLTRST# is due to chipset connectivity issues.
Download Schematic & Boardview Files
Direct download link. Verified schematic / boardview 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
