My Lenovo Legion Y540 was working normally until I took it in for a keyboard replacement because of water damage. Since the repair, it boots into Windows normally but powers off after about 1–3 minutes, apparently because of overheating or a thermal-sensor warning. The repair shop says the fans are connected, and they even tried replacing both fans, but the behavior did not change. When the laptop is completely cold, it lasts a few minutes; if they restart it while it is still warm, it shuts down almost immediately during startup. What could have been damaged, disconnected, or reassembled incorrectly during the keyboard repair?
3 Answers
The first things to inspect are the cooling system and thermal-sensor connections. Even if the fans spin, the heatsink may not be seated correctly, the thermal paste or thermal pads may have been disturbed, or a sensor cable could be damaged or left disconnected. The repair shop should compare the board and sensor connections with the service manual rather than only swapping fans.
Because this started immediately after the keyboard repair, the service center should treat the repair as the main suspect. Water damage can also cause corrosion or a failing thermal-monitoring circuit, and opening the laptop may have disturbed an already weakened connection. They should document temperatures and sensor readings with a hardware diagnostic tool instead of assuming the fans are the cause.
Try starting from a bootable diagnostic or live USB environment. If it also powers off there, that strongly points to hardware rather than Windows or a driver. If it stays running outside Windows, then software, firmware, or power-management settings become more likely.
The technician observed the same behavior based on temperature: a cold laptop lasts 2–3 minutes, while a warm restart dies almost immediately. That makes a physical thermal or sensor problem seem more likely, but I’ll still keep the live-USB test in mind.
The shop says both fans are connected and tried another pair, but the shutdown pattern is unchanged. I’ll ask them specifically about the heatsink, thermal paste, thermal pads, and sensor cables.