If your amplifier produces buzzing, humming, crackling, or other unexpected noises, this could signify a faulty unit. Additionally, if you notice that the sound levels are not as expected for specific settings on the amplifier or if it does not make sounds when operated normally, it may need repair. Lastly, suppose you hear distortion from the output speakers when playing audio. In that case, it could also mean an issue with the amplifier, and repairs may be necessary. If any of these issues occur, it is important to take your unit to a professional technician to assess and diagnose the problem accurately.