Possible Clues:

• Take apart to understand the design of
• Take apart to understand
• Disassemble and analyze
• ?rekrowoc s'rotcudnoC
• Take apart in order to reproduce ... or a hint to what's hidden in 17-, 23-, 34- and 46-Across
• Memo about a lyricist?
• Take apart (a device) in order to improve on or copy