Audio Research d79 blows plate fuse

My audio research d79 blew the plate fuse when i turned it on this morning.Change fuse and it blew also.Any help would be greatly appreciated.
Agree with Hifigeek1 - Output tube may have shorted, taking out a resistor. Needs to be checked by a qualified tech. Doubt just putting in new tubes will solve the problem.
Pka, do you intend to get a quote from ARC re the rebuild. Just curious how much they would charge.
I use Mufich Audio in Mckinney TX.He has done a lot of work for me.He is a excellent Technician.I will let you know how much the rebuild quote is.