A1418 Display not detected

[knoxy]

Having trouble with an imac a1418 (820-4668-A).

Backlight will flash on on first startup but otherwise the internal DP port is not working. Connecting to an external display works just fine.

Replaced:
F4400 with 0ohm resistor (Fuse was blown)
Display panel with known working display
Display connecter cable
Display connecter on mainboard

Curiously I am getting 12v on PP12V_LCD_F but only 7v on PP12V_LCD when the display is connected (Measured on either side of L4400)

Does that sound right and does anyone have any other ideas?

[piernov]

Re: A1418 Display not detected

Fuse probably blew for a reason. Not really a good idea to replace with a 0 ohm resistor. Measure resistance across it to check if it's gone bad again.
Measure resistance across L4400, and measure resistance to ground after L4400 with and without LCD connected.