Just looking at the PDF mbhp_4xsid_c64_psu_optimized.pdf
Little confused :-[
Isn´t the J2 at the core an 5V output?? ???
If it is what´s the use for the J1???(I dont want to burn another PIC again 
)
Christoffer
J2 can either be used as input or output, here it is used as 5V input.
A connection via J1 is not required in this case. This saves some electronic parts
Best Regards, Thorsten.