Hello. Thank you for coming to JustAnswer.
Sorry for the delay and thank you for your patience. My name is Michael. I will be helping you with your question today. I am an Expert in the Electronic Musical Instruments category. If you feel this is not the best category for your question, let me know and I will forward it to the appropriate group of Experts.
Please let me know if there as any additional information that you think might be pertinent to your question. If I don't hear back from you, I'll provide the best answer I can based on the information you've given so far. You will still be able to reply with additional information or questions at any point during our conversation, and I'll revise the my answer accordingly.
This is common over time, and the solution is simple. There is a battery in this keyboard that needs to be replaced occasionally. Part number 4347. You can get the battery from the following page - there are other places, and this is not an endorsement, just a reference to exactly what battery you need:
Please let me know if you have any other questions.