Tutorials for 9V Train Motor

[Haddock51]

In his Lego Train Book, @HoMa mentions that tutorials are available to access the internals of 9V train motors (#5300, #10153). Where can I find such tutorials? The only thing I am interested in is how to open these motors without damaging them permanently.

Edited April 3, 2018 by Haddock51

[zephyr1934]

Here is thread 1 and thread 2 that hit my radar.