Full installation manual of the older Fernandes FSK-401 Single Coil 3-mode Sustainer system produced from 2001 until 2018, with the trim pots on the back of the board.
 
Contains information, troubleshooting, wiring diagrams and guidelines for installing the system in different kinds of guitars.
 
This is the system included in most Fernandes Revolver and Retrorocket Elite (with neck single coil setup), and many Made-in-Japan models.