Robisapien V1 not walking straight?

Hello everyone... I just recently dug out my old robosapien v1 from storage. And he turned right on and started doing his thing. Everything seems to work but I notice that when I give him the command to walk straight, he tends to wander to the right, very noticeably. I put new batteries in him and he still does the same thing. I messed with his arm positions, but he still walks to the right. Is this normal? Is he broken? Is there a way to fix it? Thankyou all very much!