Display not powering on
My late 2013 iMac’s replacement display won’t power on at all: No backlight, no LCD (as far as I can tell, with a flashlight shined on it). It does boot with an external display. The internal display doesn’t even appear in System Report when looking at the list of displays.
I originally replaced this display because the old one was cracked and wouldn’t power on at all either. I’ve now tried a new display and a new display cable which hasn’t helped at all. Of course I’ve also tried an SMC reset, NVRAM reset.
The fans also run at full speed when the machine is powered on, which I suspect is just because it can’t read the temperature sensor on the new display.
Apple’s diagnostics shows two issues:
There may be an issue with the System Management Controller (SMC).
Reference Code: PFM006
I imagine this is the fan/temp. sensors? And:
There may be an issue with the display.
Reference Code: VFD001
Any idea on what I could try out next?