I while back I had the ONT replaced because of pixelation issues on the TV. It's the black box. The previous box was white. It has a D-cell battery backup. I liked the lead-acid backup. I see no way to test the batteries other than checking each one. Do I have the option of replacing the D-cell backup with the lead-acid backup? If so, can I do it myself or does a tech have to do it? How much is the lead-acid backup?