A small amount of water spilled on my desk and ran down the side of my PC. Most of it missed the case, but roughly three or four drops entered through the top and landed on the back of the motherboard. The water was very hard, so there is some dried mineral residue.
I disassembled the PC, left it for about 24 hours with a fan running, and used a dehumidifier in the room. Nothing feels wet now. Without the CPU installed, the lights and fans turn on. With the CPU installed, the system powers on but will not shut down normally, and the motherboard's CPU warning light stays lit. I thoroughly checked the power supply and found no obvious signs that water reached it.
What are the chances that the PSU, CPU, motherboard, drives, or other components were damaged? Could the motherboard still work after cleaning the affected area with 90%+ isopropyl alcohol, and is there anything I should test before buying replacement parts? Please keep the replies constructive—I already know the spill was a mistake.
4 Answers
After cleaning and drying, test with only the motherboard, CPU and cooler, one RAM stick, and the PSU connected. Disconnect the drives, graphics card, USB devices, and other accessories at first. If the CPU warning light remains on, a replacement motherboard would be the next practical test. A cheap compatible board may be useful for checking whether the CPU and RAM survived.
The motherboard is the most suspicious component since that is where the water and residue were found. Avoid repeatedly powering the system on, because mineral residue can remain conductive and cause another short. Remove the board, clean the affected areas with 90% or higher isopropyl alcohol, and let it dry completely before testing again.
Could a damaged motherboard also have taken out the CPU, or is the CPU usually likely to survive?
The PSU is less likely to be damaged if water definitely never reached it, though it cannot be ruled out without testing. The drives are probably in better shape, especially an NVMe or SSD that was not directly exposed. If residue reached the SATA connectors, replace or clean the SATA cables before reconnecting anything. Keep the drives disconnected until the board is stable.
The lack of visible discoloration or burned spots does not guarantee the motherboard is fine. A brief short can damage a component without leaving an obvious mark, and dried hard-water deposits can continue causing problems. Cleaning may help if the issue is residue, but it cannot reverse damage that already occurred.
Unfortunately I do not have a spare system or a motherboard buzzer, so I may need to test by substitution.