When I was changing the staple cartridge in my Max EH-50F electronic stapler a round bar about 1.5 inches long and two springs about .50 inches long came out. I can see where the bar goes - but it won't stay there - thinking the springs hold it in place - but can't see where they would attach. Can't locate a owners manual either here or on-line. Unit will not work with out this bar securely in place. Help...