If ...
I have a synth that has a main board with capacitors jumping across the terminals on the big chips an a small wire running from pins on the chips back into another area, and the battery numbers say I need a "new main board", what would be the chance of finding out the procedures I need to perform to change the board again---or perform some rework to fix it or can I pull the reworks off so it will function in a "default" manner?

How about this one..... IS THERE AN SD-1 OUT THERE WITHOUT ANY REWORKS ON ITS MAIN BOARD???
like I need a comparison...

Do you have an SD-1? Would you open it up and see if there are reworks on the mainboard>>>ie. chips across the large processors and little wires running underneath the main board from place to place?

Cause I want to take these things out if they are aftermarket hacks by some MAC os absuser or something...