I have some questions about my ipaq 3835.

There is a yellow light that is on just to the top of where it says
pocket pc. Right now the unit is in the charger and the light is
yellow. One time it was green. After I use the ipaq for a while and
put it back in the charger the light blinks yellow. I would assume
the blinking light means it's charging? The green light shows fully
charged? I have only saw the green light one time.

The other question is, I have a Compaq expansion pack on it. There
appears to be a light on the back of it although it never lights up or
does anything that I can see.

I think the battery may be bad in it also. Has anyone ever changed
the battery in an expansion pack before? If so what kind of job was
it and what kind of battery does it take?

Thanks in advance.