The stylus, which actually reads the record and transmits the signal, wears out over time. According to the TEAC manual for this device, that should be around 50 hours. Replacing or cleaning the stylus will help improve sound quality if done correctly, but should be done very carefully.
Unplug the record player.
Open the lid to access the turntable, arm, and stylus.
Press down on the front of the red stylus and pull forward to remove it from the arm.
Insert a new stylus by pushing it back up where the old one was, or, if necessary, clean the old one and replace likewise.