corrosion under ps/2 connector on motherboard

Question

I live by the ocean, which explains the following.

I had kept a backup motherboard in a case for my business, ready to be used when needed. When the time came to use it, it did work ... for 12 hours.

I initially thought 'power supply' and tried several with no success (fan would just spin for 2-3 seconds - fan did stay on when I mistakenly connected it to a Power supply set to 230 mode, but the computer did not boot).

I removed the motherboard and noticed there was rust under the ps/2 connector.

I put the motherboard in an alcohol bath for several hours, and much of the rust went away. But still no boot-up, fan on for only a few seconds.

A week has passed, I tried again, and this time the fan stayed on for about 6-7 seconds. Definitely longer, but still no boot up.

Is there any hope in removing the ps/2 port? could some residual rust be impeding voltage just enough to prevent bootup? The fact it worked for 12 hours and then went off (no burn marks, no apparent damage) makes me wonder if its salvageable.

Answer 1

The PS2 keyboard connector is easily removable.

You should be able to remove it and see the extent of the damage.

After that, I would recommend following any of the good guides online for removing corrosion. iFixit is the best place to start, although plenty of other how-to sites provide such guides as well.

If you are lucky, the majority of corrosion is on the shielding and only a small amount spread over.

After the corrosion is removed and the damage is assessed you have two options:

1. Repair the traces and solder back on the PS/2 connector.
2. Remove any residual shorts in the traces, and turn off the PS/2 connector in the BIOS.

Either option will make the board operational again, but option 1 will likely make the PS/2 connector work again.

As a note, if you chose Option 2 you don't have to worry about preserving as much of the traces as possible.

In the future, humidity can be kept out of your computer by adding a small pouch or container of silica gel humidity remover (which you can get at hardware stores) somewhere in the case. Only a few percentage points of humidity should do a good job to improve the life-span of your hardware.

Additionally, make sure your computer is plugged into a properly grounded outlet. This will help reduce corrosion as well, by preventing static differentials from building up on the case.