Any hints I missed? *spoilers*

[Hunter of Shadows]

I'm in Nave, reached Agrippa. tried everything to find how to fix the broken levers, so that I can open the doors. I even entered Choir, visited every room there. Then noticed it wasn't helping and returned back, couldn't find how to open those doors, so I looked it up on the internet. Then I found the secret compartment on the ceiling for the machinery.

I hate to look up for solutions, but this time I had to. I'm curious, did I miss something or was this machinery hard to find?

You have to stand on a box or something to push a gear into place if I recall correctly