On top of some generally higher grade power amps is a diagram of the schematics on how the circuits were put together. If one wasn't a gear head why would anyone care as in Parasound they don't .McIntosh,Sansui and some others do this practice. If buying new you would get a service/users manual w/ the schematics all laid out for you .On a Mac 2300 they are ther right on top. now when trying to resell most people want their silk screening and any grphics perfect .Why is this done. For someone like Terry Dewick I can't believe he takes off the top and refers to it as his guide to fix the Mac he is working on.On my previous post if I did not make it clear that Halo was one big beautiful amplifier. I would perfer and hear that it is coming out in black.