Diagnosis of Huawei D15: The main power rail is functioning correctly at 20V and is not shorted. However, there is a short circuit on the 3.3V power rail despite the presence of 3.3V on the capacitors near the EC chip. It appears that the power supply for the PCH or chipset has been compromised, with a shorted high-side MOSFET. Additionally, the coil is showing close to 0 ohms instead of the expected normal reading of around 35 ohms. This short circuit has affected the PCH side of the processor. Based on these findings, it can be concluded that the processor is faulty, and it is recommended to replace the laptop. It should be noted that laptops usually have two MOSFETs for protection after the DC jack, but in this case, the protection mechanism has failed.

There are two distinct categories of laptop issues:

Dead laptops refer to those that fail to power on when the power button is pressed. This condition can often be attributed to a short circuit occurring on one of the power rails. When a short circuit occurs, it disrupts the normal flow of electrical current, preventing the laptop from receiving the necessary power to initiate the booting process. Consequently, the laptop remains unresponsive and fails to turn on. When diagnosing a dead laptop, one of the key areas to investigate is the power delivery system, including the various power rails. Identifying and addressing any shorts or irregularities in the power rails is crucial for restoring functionality to the laptop. By resolving these issues and ensuring the uninterrupted flow of power, the laptop can be revived and powered on successfully.

Fanspin with no display. In our analysis, we are not only examining a specific set of power rails but all of them, including Vcore, which is comparable to the power configuration found in Mac laptops that turn on when the lid is opened. We are particularly interested in the power sequence that occurs after the power button is pressed. It is crucial to understand the sequence of events from the moment the power button is pressed until the system successfully completes the Power-On Self Test (POST) and the display turns on. Furthermore, we observe the behavior of the caps lock indicator as an indication of the POST completion. It is only after the POST has successfully finished that the caps lock indicator is activated, and subsequently, the display is powered on. By carefully examining these factors, we can gain insights into the overall power functionality and diagnose any potential issues with the laptop.

In my workshop, I have a diverse collection of imported tools specifically designed for repairing laptops. This comprehensive set includes a high-quality microscope and a thermal camera equipped with a macro lens, allowing for precise inspection and thermal imaging. These tools are indispensable as they enable me to work with minuscule SMD components that are as tiny as a grain of sand. To ensure a smooth repair process, I receive a continuous supply of components directly from China, including commonly used superio's, tactile push-switches, DC ports, and more. When conducting repairs, I prioritize the use of original components to maintain the integrity of the laptops. This ensures optimal performance and reliability for the repaired devices. Additionally, I offer a 3-month warranty for both the parts used and the labor involved in the repairs, providing my customers with confidence and peace of mind.