(Some receivers may use other I.F. frequencies but, for simplicity, we'll stick with our 10.7MHz which is a very common standard)
Because we are now dealing with a single, fixed frequency, note the lack of variable capacitors in this picture. The blue, yellow, black and orange coloured slots are the tops of iron-dust cores which can be screwed into or out of their coils. These are used by a service engineer to 'fine tune' the amplifier to be at its peak at 10.7 MHz - and are the ones do-it-yourselfers usually fiddle with and make things worse!