Help needed to repair or replace a 9v adapter?

Help needed to repair or replace?

How can I repair my 'In Tough' AC/DC adapter. I can't even get the thing open to fix the frayed wiring at the join to the block. This adapter came with a Korg Midi File Player i5M model. Iv'e tried other 9v adapters but they won't power this baby. Aparently it has to be this one. If it can't be repaired does anyone know a site where I can buy a new one?