151-1100-01
The 151-1100-01 is a dual JFET transistor used as the input follower of the P6202(A).
According to the 1988 TEK common design parts catalog, it contains two dies on a substrate in a lead-frame and cover package. The dies are from the 2N5911 family. 151-1100-00 might be the part number for the dies.