Now , if you take a look at Eagle front End schematic and Eagle Front End pcb screenshot (4th and 5th pics from top) said resistor positions are R3 and R53 , with R3 being position of our special interest :
My taste dictate R53 being 1K , and R3 being 1K2 ; for anyone else’s taste , all what’s needed are few different resistor values and pincette/tweezers ; just power amp off , pull resistors out (gently,please) and push new one in (gently again , please).
After that you can power amp on , or go out for beer and some talk , I don’t care