Half Mortise Drawer Lock Does Anyone Know How To Fix A Mortise Lockset Or Have A Diagram Of How Inner Meachisms Go?thanks?

Does anyone know how to fix a mortise lockset or have a diagram of how inner meachisms go?thanks? - half mortise drawer lock

I did find the fountain of me and a plaque in the form of strange [rectangular at one end, on the other side, the rounded shape of the first half rounded].

Nor have the keys.

The entire block, "said Peterboro abroad, but I can not find any information.