The implode function is used to convert an array to a string.
if you have a group of checkboxes with the same name ending in "". the square brackets crates an array.
Your code using the implode function is converting that array to comma separated string.
No extra functions are needed to convert the form output into an array in this case.
Instead of using:
((isset($_POST["1pcCB"]))?implode(", ", $_POST["1pcCB"]):""));