Which board has the memory?

I've got a double whammy going on my Galaxy S3. One, the charging port has deteriorated to the point where I can't do a backup (although I can still charge the battery). Two, I've recently been getting "The data partition has been corrupted" messages. I was going to replace the charging port until the data problem showed up. Now it seems that maybe I should replace the motherboard, because that would replace the charging port, and maybe the questionable memory in one operation.

So, can anybody verify that the data memory is on the motherboard and not some other board?

Also, has anybody had any experience with recovery from a corrupted data partition? I sure would like to do another data backup before I hit reset, but Android halts bootup at the point where it discovers the problem. It won't come up in safe mode, either.