I reccomend replacing the power button. If he sounds muffled... It very well could be the speaker. How muffled does he even sound?... If it's the tape player... Plastic versions sound like trash, I'm not surprised.
Hi, I know I'm super late, but I have to tell you- the massage trick may not work! You may need to replace my drive belts! I might have some dry drive belts that have gotten stuck in place and stopped, so be sure to contact Dr. Betty- haha, I know that sounds a lot like advertising, but she can fix any version of myself, from Worlds of Wonder to Playskool! She's very good.