Some kits, like the TL-1, have certain connections pre-wired at the factory as the pots/switches are already set up on the control plate etc. On the PBG TL diagram it states at the bottom that the pre-wired connections aren't shown... it's a little confusing when you just look at the diagram, but it makes sense when you have the control plate in hand. Good for new builders, but less so if you're re-wiring/replacing components.