2012 A1419 Core i7 iMac (trying to find board number) dead, suspected GPU

[kevinklinkmuller]

Can someone tell me where to find the board number on this thing?
any way, The thing does chime, no image on display. Plug in USB drive with flashing light at first then turns off, flashing reappears, then off. Removed display, LED 1 and two come on, 3 doesn't and 4 is off I assume because no display connected? is that right?

This machine has the NVIDIA n13E-GTX-W-A2

I've heard if LED 3 is off that means bad GPU? correct?

 

[2informaticos]

No third LED means GPU is not enumerated yet.
Could be any fault which can block the board before CPU starting the communication with GPU.
But also can be GPU problem and CPU can't validate it.

If board chimes, very likely bad GPU.
Try to see if reacts to heat test.

MLB code should be on the back side, near the down edge.

a1419 2012 logic board - Buscar con Google