I have the same problem with my 14/10. If you remove the hood you can see the battery on the lower board. Unfortunately its soldered inplace. Although I haven't fixed mine I would bet a local high end store with a repair department could replace it or you might be able to do it yourself. The battery in mine is a Sanyo CR2430 3 Volt.
Any idea where I might find an original microphone or suitable replacement? Mine quit working over ten years ago and its replacement (not original) never worked correctly. Did the origninal have a mono or stereo plug?
Hope this helps!
Thanks!