this should prob be know in trade tech but here goes.i got the straighteners in today and there is power down the lead to the small pcb but the light does not come on when you switch it on.i am gonna look more tomorrow as only looked quickly as expected a lead fault. are the pcbs prone to failure or is there any other common failured thermal fuses etc?
might sound obvious but when you say theres power down the lead did you check continuity for both the live and the neutral, or just used a light noise making thingy electricity tester to find out?