It is best to take to an experienced musical amp shop. I will try to demystify the tube based electronics. Each tube has a heater filament that causes the cathodes to emit electrons, there are "screens" between the cathode and anode that control the flow of electrons and therefor the amount of amplification.
The heater filaments are all connected in series. the first number in a tube name is the voltage for the heater filament. If a tube is out of its socket then none of the tubes are getting voltage to heat up. The heater filaments are the reason why it takes a few minutes for the amp to warm up and be ready, the cathodes need the heat to emit electrons. Heater filaments are just like the filaments found in lightbulbs.
Vacuum tubes run at fairly high voltage and the circuits can give a nasty shock that may cause muscles to contract as long as the voltage is present. This is a good reason to take the amp to an experienced tech.
You can do some checks and you may find what is shorting out the fuses. Turn off and unplug the amp and wait at least an hour or longer before you open the amp. Look for burn marks on the chassis and on the components. Use a wooden stick or popsicle stick to move wires (just in case of stored electricity) to see under the wires. The tubes get hot and make burn marks surrounding the base, but if you see a resistor or capacitor that is blackened then you should be close to what is shorting the amp.
Peavey makes rugged amps and this one should be able to handle the road after it is repaired. The hard part is to find an experienced repair tech. You can try contacting Peavey for local repair and call ahead for cost of repair.