The Peavey Bandit is a solid state amplifier. Solid state amplifiers use transistors instead of tube technology to amplify the guitar signal. The Bandit 112 has a single 12-inch speaker. It is a relatively cheap amplifier, typically used by beginners rather than pro players.
Transistor amplifiers require less maintenance than tube amplifiers. The range of common problems in such amplifiers is smaller as well. However, problems do occur, such as blown transistors and fuses. This is normally caused through prolonged usage and general wear. If you've owned your Peavey Bandit 112 for a long time, you may find this problem occurs more frequently.
Buzzing or rattling that occurs only when the guitar is played can indicate a rip in the speaker material. In such cases, get the speaker replaced. Often the speaker can become loose and will simply need reattaching to the housing.
Loose-fitting screws can cause an unpleasant rattling sound. Tighten all exterior screws to limit this. Loose wires can cause the amplifier to malfunction, too. If your amplifier doesn't turn on, there is a problem with the power section. Have a qualified repair person take a look at this problem.