I replaced my motherboard after an accident involving spilled coffee. A small amount of liquid got into the PC, so I shut it down and let it dry. When I later powered it on, the CPU power connector caught fire. I turned off the power supply immediately and found that the motherboard was the only part with an obvious burnt smell, so I ordered a replacement.
The new system uses an ASUS TUF Gaming B550-Plus, Ryzen 5 5600, Radeon RX 6800 XT, and two 16GB G.Skill Trident Z memory sticks. The replacement board now stays on the yellow DRAM diagnostic light and will not boot. I have tried different memory sticks and slots for several minutes at a time, including testing each stick individually. Could the CPU have been damaged when the EPS connector caught fire, or is there another important troubleshooting step I am missing?
4 Answers
A CPU power connector actually catching fire is a serious warning sign. The CPU may have been damaged, and a damaged CPU could potentially harm another motherboard when powered on. The connector, power cable, motherboard VRM circuitry, and RAM may also have been affected. Avoid repeatedly testing the suspect CPU in additional boards if possible; use known-good parts for diagnosis, or have a repair shop test the CPU, RAM, and board with a current-limited setup.
The RAM is still worth testing carefully. Use the recommended single-stick slot from the motherboard manual, usually A2, then test each stick individually. Make sure the module is fully latched on both ends—some slots can look seated when they are not. If neither stick works alone in the correct slot, the problem may be the CPU, motherboard, or memory rather than a simple slot configuration issue.
I spent about an hour trying both sticks in different slots and waited roughly three to five minutes after each attempt for memory training.
Since a friend is bringing a known-good CPU and RAM kit, test methodically: clear CMOS, install only the CPU and cooler, one known-good memory stick in the manual's primary slot, and no unnecessary drives or USB devices. Check that the 8-pin CPU power cable is the correct EPS cable and that there are no damaged pins or burnt connectors. Stop immediately if anything becomes hot, smells burnt, or shows signs of arcing.
Drying the liquid may not have been enough. Coffee can leave conductive or corrosive residue behind, and powering the system afterward can cause shorts or worsen existing damage. The original board and possibly other connected components should have been cleaned with high-purity isopropyl alcohol and inspected for residue or carbonized areas. Given the fire at the CPU power connector, replacing or thoroughly testing the power supply cable and power supply is also important before connecting anything else.
So there is still a chance the CPU survived, but it should be treated as unsafe until it has been tested with known-good hardware?