The Acer Aspire 5742 is a 15.6-inch laptop from Acer’s popular Sandy Bridge-era lineup, released in 2010–2011. Powered by Intel Core i3/i5 processors and the HM55 chipset, it became one of the most repaired machines in Brazil and Latin America due to its massive sales volume. This guide covers its motherboard, common hardware failures, and how to fix them.
Technical Specifications
- Processor: Intel Core i3-380M / i5-480M / i5-520M (Socket PGA988)
- Chipset: Intel HM55 Express
- RAM: Up to 8GB DDR3 (2 slots, 1066/1333 MHz)
- Display: 15.6″ HD (1366×768)
- Graphics: Intel HD Graphics (UMA) or NVIDIA GT320M / GT420M / GT540M (discrete on G variants)
- Motherboard: NEW71 LA-5893P / NEW70 LA-5891P / LA-5894P
- HDD: SATA 250GB–640GB
- OS shipped: Windows 7 Home Premium
The Motherboard: LA-5893P / LA-5891P Family
The Acer 5742 uses motherboards from the NEW71 family: LA-5893P (most common), LA-5891P (Sandy Bridge variant), and LA-5894P (Pentium/Celeron). They all share the same physical layout but differ in CPU socket and chipset configuration. The board is also used in the Acer Aspire 5741 and the Gateway NV59C.
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Most Common Failures on the Aspire 5742
- No display / black screen: Usually the discrete GPU (GT420M/540M) due to overheating solder fatigue. Very common after 5+ years of use.
- No power: Shorted MOSFETs near the DC jack or failed power IC (ADP3806 or compatible).
- BIOS corruption: After a Windows update interrupts the BIOS flash, or after a power cut during boot. Results in a completely dead machine.
- Overheating: The HM55 + GT540M combination runs extremely hot. Dust accumulation is the primary cause.
- USB not detected: Often a corrupted BIOS or a damaged USB controller on the PCH.
Community Solutions and Repair Tips
- For GPU failures (no display): Reflow the GPU BGA chip using a hot air rework station or replace the board entirely. Many techs use a heat gun reflow as a temporary fix.
- For BIOS recovery: Use a CH341A programmer with a Winbond W25Q64 clip. The BIOS chip is located near the RAM slots on the LA-5893P board.
- Thermal maintenance: Replace the thermal paste every 2 years. The factory paste on 5742 units degrades quickly. Use MX-4 or Kryonaut for best results.
- Power failures: Check F1 fuse and the MOSFET Q1 near the DC jack. A bench power supply with current limiting helps identify short circuits.
Get BIOS Files and Schematics
Need the original BIOS ROM file for the LA-5893P or LA-5891P? We carry verified BIOS binaries and schematics for the Acer 5742 series in our Mercado Livre store: