It could be a loose connection behind the board. Also, wylex boards used to have a din rail in the board to mount door bell transformers at the end - the rail or door bell transformer could be vibrating.

Why is my fuse board buzzing when I'm using the shower?
I've tried:

In[169]:= newton3[x_] := N[1/2 (x + 3/x)];
FixedPointList[newton3, 1.0]

Out[170]= {1., 2., 1.75, 1.73214, 1.73205, 1.73205, 1.73205}


Of course:

In[164]:= N[Sqrt[3], 20]

Out[164]= 1.7320508075688772935


How do you use the FixedPointList to increase the number of decimal places?
