Power rectifiers usually short, causing the main power fuse to blow. Once
in a while a section of a bridge will open and a hum will be heard in the
speakers. If you are in doubt about the rectifier being bad, it is
probably okay. Check the plus and minus voltage at the large filter
capacitors to ground, if they are equal, the rectifier is okay. If you
need that rectifier though, just replace it with something having a higher
amp rating, and at least 200 piv, the higher the better. Very few items
in that receiver will require a Kenwood part.