Have you ever seen this BC working? With your own eyes or ears?
Are you the owner? Or bought it later? With unknown defect?
OK, start again.
Call it transformer. If you connect the transformer to the regulator power board it blows the fuse.
Easy. Connect a regulated powersupply instead the transformer to the regulator board.
Maybe one of the 4 diodes of the rectifier have blown. Or C3 2200uF has a short.
But if the BC could be working in Standby and reacted to keys… and then it blew the fuse: C6 10uF is dead.
Were any caps already replaced? In the correct polarity? A cap in wrong position will make you have a nice day…