The ornamental design for a portion of a base for a joystickcontroller, as shown and described.
FIG. 1 is a perspective view of the portion of a base for a joystick
controller showing my new design;
FIG. 2 is a first elevational view thereof;
FIG. 3 is a second elevational view thereof taken approximately 90 degrees
from the first elevational view of FIG. 2; and,
FIG. 4 is a top plan view thereof.
The bottom of the base forms no part of the claimed design. The broken line
showing of the remainder of the base in FIGS. 1-4 and the handle in FIG. 1
is for illustrative purposes only and forms no part of the claimed design.