Not powering up at all

@teogboin Start off with the easy things. Disconnect the power from the computer by unplugging the power cord from your computer. Disconnect all external devices from the computer. Disconnect the battery Now hold the power button depressed for about 30sec-1min. Reapply the AC power adapter and see if your computer does show any sign of life.

Now, here are some generic steps you have to take for the initial troubleshooting. First you need to check your power supply. Make sure it has the proper voltages. Check to make sure that the connectors are not bend etc. Check the DC-in jack of your laptop. Make sure there is no corrosion, debris etc. that prevents it from working. Clean it of any debris etc, use a few puffs of air to clean it out. If none of this works, get a ammeter and see if your laptop draws any amperage from the charger. After that, you need to check and see if your motherboard even gets power. For that of course, you need to open it up. Post Some good pictures of what you see. That way we can see what you see. 在已经存在的问题里加入图片

Let us know what you find out. Use the Lenovo ThinkPad L490 And L590 Hardware Maintenance Manual to work on your Lenovo