I have two malfunctioning laptops, excluding the one I am using to write this note. I suspect the issue is related to the power supply, but the actual problem could be anything. I’ve learned that one of the quickest ways to diagnose the problem is to check for a short circuit on the motherboard PCB.
The fastest way to detect a short circuit is to test for continuity between an inductor and the ground. There are many inductors on a PC or laptop motherboard, and they are typically connected to power supply lines (such as 1.5V, 3V, or 9V) but never directly to the ground. If a continuity beep occurs between any inductor and the ground, that part of the circuit is likely shorted.
Once such an inductor is identified, the connected components should be inspected. For example, a graphics card IC might be linked to an inductor, so both the IC and its surrounding capacitors should be checked. If the capacitors are shorted, there will be continuity between both sides of the capacitor and the ground (or casing).
For more detailed testing techniques, refer to my earlier notes:
