CHECK or REMOVE your old BATTERIES

[tinyJazz]

I forgot my Device Label Soundwave when I removed my tf batteries. :| better check him when I get time, I don't know where he lives these days.
As for MP04 I couldn't for the life of me get the battery holder out. Then again, I have trouble opening soda bottles sometimes. I'll have to recruit someone and try again.

[Tetsuwan Convoy]

I forgot my Device Label Soundwave when I removed my tf batteries. :| better check him when I get time, I don't know where he lives these days.
As for MP04 I couldn't for the life of me get the battery holder out. Then again, I have trouble opening soda bottles sometimes. I'll have to recruit someone and try again.

Not sure whether or ot you saw this, or how good you at making out Japanese in instructions, but there is a scan for this very problem right Here. Provided by some helpful citizen
Actually that's not that helpful... lol, IIRC, when you get to the twisting the matrix box around step in the second pic,(4th I guess) then you should be able to slide the peg out of the bit it is hooked in to with a bit of jiggling.

getting it back in again, well THAT'S another story.