A Matsushita Technics SL-P10 compact disc player has been successfully converted into a prototype magneto-optical disk drive. The project demonstrates the feasibility of dynamic read and write using low cost, currently available components. Specific modifications to the compact disc player optics and electronics include: (1) the optical pickup, (2) the tracking servo, (3) the signal amplifier, (4) the continuous linear velocity rough servo, (5) the laser driver, and (6) the addition of a bias field electromagnet. The prototype still retains the ability to read from a compact disc. Music (encoded in the compact disc digital audio format) has been recorded and played back. Quantitative measurements of the system are presented, including spectrum analyzer traces of noise levels and data from recording single frequencies. An optical computer disk drive (CD ROM) and a compact disc digital audioplayer share similar optical pickup sections and thus the modifications described in this paper can be utilized for both the audio and the computer data applications. The prototype may be used as a test apparatus for optimizing media performance and conducting media lifetime tests.