Chosen Solution
Hello! Opened it up to replace a failing HDD. While I had it open, I inspected the rest of the machine and saw this:
This is the back of the logic board, just above the processor.
The corrosive material wipes away easily without solvent. This is a cold region, it is possible the machine has been exposed to near or sub-zero temperatures in the past. The corrosion appears to only be in this area, the rest of the board seems fine. No other signs or suggestions of a spill or water intrusion.
My plan at the moment is to clean it up with 99% alcohol and to remove the logic board so I can check the other side. I don’t have the right size bits with me right now so that will have to wait until tomorrow. After that and reassembly, I’ll tell the owner to keep it warm from now on, I strongly suspect this is the result of cold and humidity.
My question is, is this the right conclusion? Or do you think this board is likely to fail? If so, I might as well replace it while I have the screen off.
Let me know if there’s anymore info I can provide.
Thanks
Update
I’ll be replacing the heat sink as per @danj’s response. The white corrosive material is indeed coolant which escaped from the heat sink tube through a pinhole and condensed on the board. I’m amazed at the accuracy of the diagnosis @danj made.
I don’t think this is corrosion! I think you are seeing the evaporation of the coolant that was within your heat sink heat transfer tubes, leaving a white deposit.
You’ll need to carefully inspect the tubes for a pin hole or split if the system froze. The bottom line you’ll need a new heat sink.
