To perform a repair on a CD player, first determine the exact problem, such as the radio display being blank, the player's tray sticking or the audio skipping. The player may also produce poor quality sound or at a low volume.
If the player display is blank while there is a CD inside it, check whether the CD is inserted properly, specifically whether it's upside-down. If there is an issue with the quality of sound or its volume, first inspect the speakers: Disassemble the speakers, and check for dirt or signs of damage. Also, check whether the wiring is properly connected.
If the CD player's tray gets stuck, remove the optical deck, and examine the drawer mechanism for loose or broken parts. Next, check whether the belt is tightly attached. If it isn't, replace it. If the tray still gets stuck, examine all the gears and electric motors for burn marks or damage.
If the audio skips, first check whether the CD tracks are dirty or damaged. Test newer CDs on the player to confirm whether the skipping problem persists. If it does, open up the CD player, locate the objective lens, and clean it using isopropyl alcohol. Examine the lens afterwards. If it has major scratches, you have to replace the entire lens assembly.