Recent studies on technology have shifted from the emphasis on technology skills alone to integrating pedagogy and content with technology--what Mishra and Koehler (2005) call technological pedagogical content knowledge (TPACK). Deeper understanding on how TPACK can be cultivated is needed. This design-based research explored how an improvised, problem-based learning approach guided by the SECI framework (socialisation, externalisation, combination, internalisation) can help in-service teachers to cultivate TPACK. Data were collected via self-progress surveys, reflections by the in-service teachers, student produced artifacts, records of overall course design, and log entries by the instructor. Based on the survey data, teachers believed that they had developed TPACK. By comparing the qualitative data from two groups, it was discovered that teachers became better positioned to use TPACK more fruitfully after their mental models moved towards Biggs's Level 2 and 3 approaches in teaching. The course created critical but safe opportunities for teachers to better understand that technology in itself is not likely to improve ineffective teaching practices; and, in selecting technology, teachers may have to reevaluate their teaching practices and to rethink the nature of the subject that they teach. (Contains 3 tables.)