A very easy to understand and use manual. Well worth the money.
Text excerpt from page 18 (click to view)
1
N Is 1-Pin of S-80752AN (DET 1) 5[V]? Y Is 11-Pin of CPU (LSI 1) sending the signal? Y Is 13-Pin of CPU (LSI1) sending the signal? Y Does RAM make positive contact with PCB? Y Replace RAM (LSI2 or LSI3) or CPU (LSI1) N Resolder RAM (LSI2 or LSI3) N Replace CPU (LSI1) N Replace CPU (LSI1) Replace DET1
< No key input >
Does key make positive contact with PCB Ass�y
N Replace PCB
Y Does CPU make positive contact with PCB? N Resolder CPU (LSI1)