The actual latch is located inside the top of the column…….access thru the top of the column……
The handle at the front of the saw connects long rods to the latch……..
Open the top and see if the latch is working…..clean and lube any working parts……
Visit Sears Parts and enter Model # ……….See the UNIT diagram……a replacement Manual is available…….
http://www3.sears.com/