You can start to check if you have the fuses by removing the filter on the back of the scope, removing the little screws that hold the fan and moving the fan aside - no need to disconnect it. The fuses are short Buss fuses - the top two items on the diode board. You can't easily see this from the sides.
The fuses were provided with the diode board with mod kit 040-0223-00.
There was another mod kit to just install the fuses, using a short ceramic strip on the underside of the chassis.
I wonder if the transformer killing shorts were more common with the selenium rectifiers as that is a known failure mode. Still good to have as this is a high current 15 volt circuit.