Once you've put a good fuse back in, you can perform some simple tests to determine if your power transformer is probably ok or shorted or you have some dangerous wiring condition existing that needs correcting before plugging this thing into the AC mains again.
With the power cord unconnected to the power supply and the AC mains:
(note: To learn to do all the tests I have suggested properly or to see this effect properly, try this test on a known good piece of transformer powered equipment...remember it is unplugged from the mains when you make this test!
First, set your DMM to the lowest ohm scale you have, or to the 0-1 or 0-1.999 ohm scale. Measure the resistance between the two AC mains pins on the 3-wire power socket. The green wire is the earth ground and the other two connections are the AC mains and are together above or below the ground wire third wire. You should see a quite low resistance, but be careful here to notice that the ohm meter will take some pause to attain a low-ohm reading than if you just connected both of your probe tips together..this pause time indicates probably your power transformer is good.
You may have to switch the power switch on the unit to get a reading. You should see an open circuit at one position of the on/off switch, the (ohms scale over range)
if the power switch is not connected or is not connected properly, you first need to get the switch circuit to work properly before any of the other test to work.
If you turn the power switch on and off and see a low resistance in both positions of the power switch, you have a wiring problem. If you turn the power switch on/off and you see always an open circuit, then the problem is not the transformer but the wires going to the transformer and the AC mains power connected to it and you probably have some dangerous wiring
Secondly, put your ohm meter on a high scale, mega ohms scale, and measure the resistance from either side of the power mains pins to the chassis ground, if you see any resistance lower than in the meg-ohms your transformer may be shorted to ground by wiring or an internal fault in the transformer and you need a new power transformer. If you disconnect the power leads to the transformer and toggle the power switch and still see a low resistance across the AC power pins or from either power pin to ground you have a dangerous wiring problem that must be corrected before playing again with the transformer.
Thirdly, if you verify no direct connection to ground (low resistance) from either AC mains power jack pin, you can make a good check of your transformer with your scope:
Connect your scope directly across the power pins (of course with the power cord disconnected! ) if you measured a low ohm or fractional resistance measurement across the power pins previously with an ohm meter. Use a 10x probe and set your scope input to Auto Trigger and about 100mS/sec time div and volts to 10V/div or so and trace free running.
Now take your ohm meter and set it to a diode-transistor test or ohms scale and touch the probes across the scope leads connected to each of the AC power pins the AC mains connector. You should see a short sharp HV spike as you quickly remove one or both of your MM probes on the low ohms scale. This indicates a good power transformer.