Systems and methods for detecting the presence and/or location of defects (e.g., incomplete solders, broken cables, misconnections, defective sockets, opens, shorts, etc.) along electrical lines are described. The systems and methods described herein may use time-domain reflectometry (TDR), a measurement technique used to determine the characteristics of electrical lines by observing reflected waveforms. TDR may be performed in some embodiments by determining the times when a first event and a second event occur, and by determining the space traveled by a probe signal based on these times. The first event may occur when a first signal transition crosses a first threshold and the second event may occur when a second signal transition crosses a second threshold, where the second signal transition may arise in response to the first signal transition reflecting against a defect along the electrical line.