Powerbook 540 is the same as Powerbook 540c, with the exception of the display, which is grayscale active-matrix LCD screen.
The leaking battery destroyed one of the pins of the voltage controller IC LTC1148HV. I managed to uncover it with Dremel and solder a bodge wire directly to the IC internal part of the pin.
Display is a Hosiden MTFT active LCD matrix, it is prone to so called tunnel effect. I followed some advices on the Internet to bake the display in an oven, but it did not help much. I baked it only for two hours at 85 centigrades, so maybe this was too short too cold.
Display backlight inverter
Display Connection Board
240MB Conner CFN250S. The disk was not spinning up initially, opening it up and moving the plates helped to get it unstuck.
Floppy Disk Drive