Rear derailer refuses to travel from top to low gear

[cny-man]

Sounds good, but the sheldonbrown and parktool sites are written (with some pics, not videos. Videos often leave out a lot of important info, and don't always provide an easy way to look up related item to the item you are interested in. I suggest going to a video only after studying and understanding written procedures, just to see the process in action.

The only further idea is to stop randomly trying things and follow standard steps. Otherwise you will just get confused and possibly introduce new problems.