Chosen Solution
Hi all, Display flickered and went dark while using it. Backlight is working, and external screen is working through another mac connected by thunderbolt; everything else also working fine via external mac. Have reset NVRAM and SMC to no avail. Also tried reconnecting LCD cable (but only on logic board side - haven’t tried doing screen side yet) - this made a small difference as display worked on startup for about 10 seconds, before flickering and going dark again. Another forum suggested it may be the logic board? I am fishing for other tips and tricks or diagnosis steps I can try first as this is an expensive replacement for a 2nd hand (refurbished) machine. I live remotely and difficult to get to a tech. Is there a layman’s way to test the logic board? Any advice much appreciated.
Connecting two Macs via Thunderbolt is not the same as an external display (screen sharing or via Target Disk Mode). All you’re doing is sharing the screen or accessing the drive, not testing the systems ability to push a screen natively. Even still it’s a good sign! You’ll need to try a VGA or HDMI connected external display that way we know the GPU logic is OK and we only need to worry about the internal display.
