A blown fuse means that the device tried to draw too much current for one reason or another.
I will occasionally get the customer who claims there was a "power surge," or thinks there might have been a "power surge." The customer believes some external force reached in and zapped the fuse. This is always wishful thinking on the owner of the equipment. The equipment has a fault and needs to be serviced.
Troubleshooting equipment that has a blown fuse can be straightforward: you inspect the power supply and any "power" devices (power transistors, power tubes) and look for low resistance readings and visible burnt up components. Often this will reveal the source of the excessive current draw and you're back in business after replacing a few components.
Unfortunately there is a very good possibility that after replacing several components (including new fuse) the device will begin to smoke and fail again... perhaps ruining your brand new replacement parts in the process. And you are back to square one.
You can keep inserting and blowing up fuses (which aren't cheap!) as long as you want, but there is a better way.
The LIGHT BULB LIMITER is a very handy thing to have when you don't want to waste your fuses. The limiter uses the properties of a regular incandescent bulb to prevent a shorted device from drawing any more current that the bulb would normally draw at full brightness.
The trick is to wire the light bulb in series with the device under test. This is easy than you think. All you need to do is wire up an electrical junction box with a dual outlet wired up in series. To wire in series, you will take the incoming HOT wire and connect it to a HOT terminal on the outlet. Then wire that same outlet's NEUTRAL to the second outlet's HOT terminal. Finally, connect the second outlet's NEUTRAL to the outgoing NEUTRAL wire. Don't forget to ground the box!
You will probably need to remove any metal jumper that is probably installed to keep the dual outlet's two HOTs together and two NEUTRALs together (normal parallel wiring).
Wiring up a simple ON/OFF switch is a good idea too.
It's also convenient to BYPASS the bulb when you're done playing it safe. I've never put such a thing on a switch, but I do have a shorted wall plug that is firmly attached to the limiter box (don't want to short a normal outlet!!) that I can plug in to test things. It is also useful to test the full brightness of the bulb, or just use the bulb as an auxiliary lamp.
The maximum current can be figured out with simple Ohm's Law. Since P=IE, a 120W bulb with 120V wall voltage will have a maximum current of 1A. My go-to is a 100W bulb, which limits things to about 833mA. This is usually plenty to turn on most things. You may want a smaller wattage bulb for low power devices and a higher wattage bulb for high power devices. This is not critical so long as your limit is under the fuse value.
More bulbs can be wired in parallel to give you more maximum current. I have 2 sockets wired in parallel and I keep 2x 200W bulbs around for big amps.