A PCIe bus extension system, method, interface card and cable for connecting a PCIe-compliant peripheral device to a PCIe bus of a computer system. The method includes the following: monitoring the load of the power converter system; using leading edge modulation for the PWM signal under light load condition; and using trailing edge modulation for the PWM signal under heavy load condition; thereby optimizing operation of the power converter system. A window covers the distal end of the first lumen so that the user can use the endoscope to view the guide probe and the general area surrounding the guide probe. A second bearing support member is installed via a second elastic member between the guide section and another retaining section of the slider.