1. Check your cables. Make sure that all of your cables are properly plugged into the correct jacks and that they are in good condition. Try swapping out cables to see if that resolves the issue.
2. Check the amp settings. Ensure that the amp is turned on and that the volume is turned up. Check that the input and output jacks are properly plugged in and the speaker is connected correctly.
3. Check the speaker. If you have an external speaker, make sure that it is properly connected and that the impedance matches the amplifier's output impedance.
4. Try the amp with a different guitar. If you have another guitar, try plugging it into the amp to see if the sound works. This will help you determine if the issue is with the amp or the guitar.
5. Check the power supply. Ensure that the power supply is properly plugged into the amp and that the voltage is correct.
6. Check for loose connections. Inspect the amp for any loose connections, especially around the input and output jacks and the speaker terminals.
7. Check the internal components. If you have the necessary skills and knowledge, you can open up the amp and check the internal components for any damage or loose connections.
8. If none of the above steps work, it may be time to take the amp to a qualified repair technician for further diagnosis and repair.