A few drops of hard water spilled onto my desk and ran down the side of my PC. Most of it missed the case, but around three or four drops entered through the top and appear to have traveled down the back of the motherboard. I disassembled the computer, left it for about 24 hours with a fan running, and used a dehumidifier in the room. Nothing feels wet now, although there is some dried residue on the motherboard.
With the CPU removed, 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 found no obvious water near the PSU, and there are no swollen or discolored components.
How likely is it that the PSU, CPU, motherboard, drives, or other components were damaged? Should I clean the motherboard with high-concentration isopropyl alcohol, and what would be the safest way to test the parts without causing more damage?
4 Answers
If the PSU was not directly exposed, it is less likely to be damaged, but you should not open it to inspect the inside. The drives are probably okay if water never reached them, particularly an NVMe drive. If residue may have reached the SATA connectors, replace the inexpensive SATA cables before reconnecting anything. Back up or test the drives only after the system is stable.
Disconnect the drives and graphics card, remove the motherboard, and clean any affected areas with 90% or higher isopropyl alcohol. Use a soft brush if there is visible hard-water residue, then let it dry completely. After that, test with only the motherboard, CPU, one RAM stick, and PSU. Ideally, try a known-good replacement motherboard or PSU rather than guessing from the lights alone.
The CPU warning light does not automatically mean the processor is dead; it can simply indicate that the motherboard cannot initialize it. Without a case speaker or diagnostic buzzer, the light is the main clue, but a known-good motherboard is the best way to separate a board failure from CPU or memory damage.
The motherboard is the most likely casualty, especially since the water apparently ran across its backside. A motherboard can fail from a short even when there are no burn marks or visibly damaged components. I would avoid repeatedly powering it on, because a remaining mineral deposit can create another short.
Could a damaged motherboard also have taken out the CPU?