Black wire, hot, on AC cord connects to the brass terminal on the accessory outlet. From there to the INSIDE contact of the fuse-holder. Outside contact of the fuse-holder goes to the Power switch. Other side of Power switch goes to Power Transformer Primary.
White wire, return, on AC cord goes to the silver terminal on the accessory outlet. From there to
other Power Transformer Primary lead. The AC ground switch makes a good place to do this return/primary connection.
If you have another brand of guitar amp just look at the schematic in the lower right corner of the picture below.
AC cord Black: To fuse, to switch, to PT black wire.
AC cord White: To other PT black wire.
AC cord Green: To ground, usually a ground lug under a transformer bolt. Make sure there is a locking nut on it.
Snip or unsolder the death cap. Also make sure the strain relief is working properly when you install the new AC cord. Get a new one if you have to.