A troubleshooting activity was carried out by an e-tutor in two steps. First, students diagnosed a mistaken statement and then compared their diagnosis to a teacher's diagnosis provided by the e-tutor. The mistaken statement involved a widespread tendency to over-generalize Ohm's law. We studied the discourse between pairs of students working with the e-tutor to examine whether and how the activity attained its objective of engaging students in knowledge integration processes; namely to "elicit" students' ideas, "add" scientifically acceptable or non-acceptable ideas and support them in "developing criteria" to "sort out" their ideas. We focus here on two case studies involving a pair of students with high prior knowledge and a pair with poor prior knowledge. The micro-analysis of these two pairs shows how the activity triggered students to explicate multiple alternative interpretations of the principles and concepts involved and attempts to align conflicting conceptions. We discuss how successive emendations gradually culminated in the elaboration of the students' understanding of these concepts.