I do not have an extra logic board. But if you want it for this mod, you do not need it. I have a different method that requires no alteration of either the LCD or the neck. Nor does it require any components from a cinema display or other monitor.

I am currently putting together a Sandy Bridge based 20" iMac G4 All-In-One Mod based n this new approach.

See this Guide for details if interested:
The iMac G4 forever changed the way I viewed computers. With some modification it can be used as an external monitor or updated all-in-one computer.