iMac 27 5k, 820-00609-A, only 2 leds turn on, Fan's full blast, No image

[SpinNNN]

Hey guys,

I'm Working on imac 27, 820-00609 MB that only light up the first 2 leds..

From your experience with this model, is it common for the graphics chip to die?

The board is very clean and I can't find anything wrong with it.

I have all the correct voltages at the outputs of the processor and graphics chip power coils.

is it worth trying bios programming?

thanks

 

[2informaticos]

Is worth to try BIOS.

Any history available?