Atari 800 adjustment of coil on main board

[Sean39]

Hi everyone

 

I have a question. If you open an Atari 800 from the botton and look at that main board there is a small opening hole. This goes

to a coil next to a chip. What is this coil for I have notice it affects the sound,but what is it for and how do I adjust it correctly????

What frequency is the Crystal on that board at too because I notice it has no frequency on it and I also notice it being in the atari 400 too.

Anyways does anyone have a schematic of the Atari 800 or 400 computer???

 

 

 

 

 

 

 

 

 

sean39