My group has been using a 1260 infinity HPLC with isocratic pump. Recently, we found that the sound from the isocratic pump of our HPLC is louder than before but everything is working fine so far. One day, our HPLC screen showed the error message saying that the pump motor has exceeded the maximum limit. After this message was found, we cleaned the inside of isocratic pump and ran the HPLC again. Although HPLC after cleaning worked fine, the sound from pump was still loud. Can anyone help me to resolve this issue?