The Acer Aspire 5332/5732 series, built on the robust Compal LA-4853P (NAWA2) architecture, represents a classic era of Intel GL40/GM45 chipset engineering. While these machines are known for their longevity, they frequently arrive at the repair bench with common aging symptoms: no power, intermittent charging, or failure to post due to Southbridge (ICH9-M) thermal stress. This guide provides a deep-dive into the chip-level logic of this specific board to help technicians navigate complex power-rail failures.
Board Architecture & Technical Specifications
| Feature | Technical Specification |
|---|---|
| Motherboard Model / ODM Part Number | Compal LA-4853P / LA-4854P (NAWA2/NAWAA) |
| Target Laptop Series | Aspire 5332, 5732, 5732Z, 7715Z |
| Chipset / CPU Architecture | Intel GL40 / GM45 + ICH9-M (Socket P Penryn) |
| Super I/O (EC/KBC) Controller | ENE KB926QF D3 |
| Key Voltage Rails & Switching Coils | +3VALW (PL24), +5VALW (PL25), +VCC_CORE (PL21, PL22) |
Real-World Motherboard Diagnostic Procedures
1) Input Power Stage & DC-IN Protection Circuit
On the LA-4853P, the first 19V rail (+19VB) is governed by two P-Channel MOSFETs, PQ1 and PQ2 (typically AO4407A). If the laptop won't turn on and there is no voltage on PR15 (the main current sense resistor), check the gate voltage of PQ1/PQ2. This gate is controlled by the Charging IC, PU1 (ISL6251). For the MOSFETs to conduct, the gate must be approximately 9V lower than the source. If the gate is at 19V, the ISL6251 is likely detecting an over-voltage or short circuit. Verify ACIN at Pin 23 of PU1; it should be around 3.2V. If ACIN is missing, the EC will never receive the ACAV_IN signal, and the system will remain dead.
2) Standby & Secondary Rails Generation
The +3VALW and +5VALW rails are generated by PU11 (TPS51125 or RT8205). These rails must be present even when the laptop is off.
- Check PL24 for 3.3V and PL25 for 5V.
- If missing, check Pin 13 (EN0) and the LDO outputs: Pin 8 (VREG3) and Pin 17 (VREG5).
- Technician Tip: This era of Compal boards often suffers from ceramic capacitor leakage on the +3VALW line. If PL24 shows a resistance to ground lower than 100 ohms, use a thermal camera or the "IPA evaporation method" while injecting 1V to find the shorted decoupling cap (often near the Southbridge or EC).
3) Power-On Sequence & Signal State Tracking
When the power button is pressed, the ENE KB926QF (U31) triggers the power-up sequence. Track these signals in order:
ON/OFFBTN#: Drops to 0V at Pin 32 of U31 when the button is pressed.PBTN_OUT#: The EC sends this to the ICH9-M Southbridge.PM_SLP_S3#andPM_SLP_S4#: The Southbridge must release these signals (3.3V) to enable the secondary rails (+3VS, +5VS, +1.5V).- If the laptop turns on for 2 seconds and dies, check the voltage on PL21/PL22 (+VCC_CORE). If the CPU core voltage never appears, inspect PU10 (ISL6266A) and ensure the
VR_ONsignal is reaching Pin 44.
Download Schematic & Boardview Files
Direct download link. Verified schematic / boardview archive for LA-4853P.
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
