Imac would not boot up (LED #1 lit only) about 9 months ago so I replaced PSU at that time. iMac was working fine until recently when it would not boot up again. Only LED #1 lit so I replaced the PSU again thinking this would solve problem……it did not. Only #1 stays lit and SuperDrive starts to spin yet no fans or chime or screen.

Question: Any other checks before logic board needs to be looked at or replaced. Is it worth replacing logic board on 10 year old iMac? How long and any special tricks?

Thanks from Florida.