An apparatus and method for supporting a device for processing an
electronic component substrate includes an assembly supporting a laser
lens in a gravity field for focusing movement along a Z-axis by a linear
actuator. A fluid counterbalance for the assembly is defined by a piston
associated with a housing for movement between end limits of travel. The
piston divides the housing into first and second fluid chambers having
first and second fluid communication ports. A fluid pressure source is
connectable to the first and second chambers through the first and second
fluid communication ports. The fluid pressure source is adjustable to
statically suspend the supported laser lens in equilibrium within the
gravity field. The fluid pressure source permits movement of the
supported laser lens to any position between opposite end limits of
travel of the piston, while maintaining the mass of the supported laser
lens in equilibrium.