Replaced the PSU, Logic Board and Cable - Still disconnecting
My Apple 27” Thunderbolt display started disconnecting and the screen would blackout.
I’ve replaced the TB/Magsafe cable, the power supply, and the logic board. The screen is able to show an image - but only for a few seconds before going black again. If I unplug the cable from my mac and immediately plug it in again, the image does not come back. But if I wait 5-10 minutes and plug it in again, the image show up briefly before the screen goes black again.
In “System Report” there is nothing connected to the thunderbolt port when the screen is black. So it’s not detecting the logic board I assume.
The MagSafe is able to charge my Macbook Pro so I do not suspect the EMI filter is cutting out, as the PSU would have no power or at least intermitting power. The charge light is solid.
Can it be the backlight of the LCD panel itself that is broken? It is able to light up, so maybe some driver circuitry? The reason I am not sure is, when the display goes black, MacOS blinks like the screen is physically disconnecting. To my understand, the backlight driver is “dumb”. It would not cause the thunderbolt connection to drop.
I’ve tested with three different Macbooks.