Thank you for the info, Jim + Robert ....
It sure does help and makes a lot of sense. I will have to consider this when collecting, as before this day I had no idea about the primary and back-up chips. I greatly appreciate the replies to that question .... each day I learn and each day I am less of a newbie to the hobby. Now the fun part, finding a member that may have the chips I am "In search of ..... "