Link Trainer

I wondered if anyone has any pictures of inside the link trainer ie the workings ,wiring etc as on saturday i shall be picking one up which i have got to restore ,
I have not seen it yet but what i have been told it may be a d4 .and is still mounted on its hexagon frame.
It is a early d4 i was told but was told a rough year of 1947 which means it could be a earlier mark ? but d4 was mentioned.
I am also looking for any diagrams of systems ,electrics and any general information on the workings of the systems if any one can help as i think i have a nice winter project on my hands.
I shall tackle the location of instruments when i get it back on saturday as i kow the panel is bare.
If anyone can help me in any way it would be greatly appreciated.

Thank you