The battery would no longer hold a charge and needed replacement.
I followed the directions to the letter and had no problems. Good eyesight was a must as the soldering is very detailed. Being older I had to use a lighted magnifying glass several times to see exactly what I was doing with the soldering tool. This was the first time I had ever used desoldering braid and was very impressed with how it worked.
Take it slow and easy and don't rush yourself. Follow the directions step by step. Take your time.