The screen resistors are missing. This will cause the fuse to blow. This is not the capacitors. The design of the output tube was changed in the early 70s. The design change cause the tubes to draw more screen current. This is why the screen resistors were added to the circuit. If the resistors are not installed, the screens will draw too much current and the fuse can blow. This is not caused by any capacitors. 1. Put the amp back to stock. 2. Install the screen resistors. 3. Verify the speaker load with an ohm meter. (make sure the output tubes are good) 4. Set the output tube current. Then the amp should not blow fuses.