CMOS Battery Repair | Toshiba Satellite pro 4200 series

I have a pretty good working Toshiba Laptop, which was at the time 1998/99 a top of the line device which could compete with IBM Thinkpads. The only problem is the faulty CMOS Battery which gives an error message during every boot up. I want to rapair this. This Video also helps you, if you want to take a similar Laptop apart.