Does the RRD Fan extender have anything connected to the servo 0 or servo 1 slots (D6, D11) or to the v+ bus shared by the four servo slots? Is there a schematic or board layout image available? I just upgraded my printer to a dual extruder, and I want to use the RRD extender to drive my cooling fans, but I also want to plug in the servo to drive my auto-level probe. I can solder on a wire tail or something like that if needed to get at the servo pins, but I wanted to know if there are any connections that might effect servo operation. I tried doing the wire lead soldered off of the pins to my servo, but the servo didn't work: It's possible the servo is dead (or is dead now, at any rate), but I want to rule out misconnections before I replace the servo. I would like to recommend an update to this product: Extend/duplicate the pins not used by the fan extender, so that servos can be stacked on top, or use a smaller header block so that the unused servo pins are not blocked.