I bought this synth as a new in 1989. Now the internal battery reported it is dead and it needs to be changed. I new that all the internal sounds will get corrupted in this operation. That's not a problem because there was only one sound that I had programmed. Here is a picture of the main-board where you can see the yellow CR2032 battery. The other picture shows my V50 together with analog-friends SH101 and TTSH2600. I think now I am ready to program more FM-sounds. I have the book "FM Theory & Applications" by John Chowning and David Bristow and the original operating manual for V50. Now I must just start to create new sounds.