Apple iMac 27" A1419 Logic Board 820-3478-A - No power

[Melamanti]

I have tried with another PSU, replaced isl and bios but it wont start, only the first led lights up, any ideas?

 

[2informaticos]

Means 3V3_S5 is present.
Check if PM_SLP_S5_L pulse at least when trigger SMC_ONOFF_L.
If yes, 5V_S4 should pulse too.
Any history available?

 

[Melamanti]

i had to return this machine to the customer so i didn't have time to repair it, you can close this