A mbr is nothing more than data written to the beginning of a hdd http://en.wikipedia.org/wiki/Master_boot_record By rights a check disk scan will fix it however read on Start with the manufacturers check disk utility to determine if physical sectors are damaged on the hdd not doing so will mean any revival attempts will be a waste of time if the platters themselves are stuffed You would be better off placing the hdd in a computer as one poster has stated http://www.tomshardware.com/forum/259002-32-corrupted-external-hard-disk
The long test did you tick repair & did test fail if so check on manufacturers website if your hdd is under warranty & start an RMA,Model & serial number will be required if you re-open seatools & locate help in tool bar it will show the log its the txt file with letters & numbers
No it's not an electrical issue it's hardware a bad lba is the discs themselves only one solution hdd needs replacing
You could open it up & place it in a clear case & have it on show,take the magnets out tho as they're freak'n strong & real handy,look at this way you put one on a fridge you'll need a prybar to get it off,no! i'm not exagerating