3476 VCORE=1.7V No USB light/activity, no display

grmacs

Member
When connecting to external the monitor seems to detect something but then says no HDMI connection - so seems as though some sign of signal from HDMI connector but definitely not booting. NO chime. THis does SMC reset. Hard to tell if it is PRAM resetting.
Turning on:
Power button, 2 seconds later = fan spin, about 12 seconds after power-up fan pauses for about 3 seconds, then spins again for about 10 seconds and pauses for 3 and repeats.

Reflash the firmware?
 

2informaticos

Administrator
Staff member
With PLT_RESET_L low, power on sequence is not completed.
What about PM_PCH_PWROK and PM_PCH_SYS_PWOK?
Also check CPU_VCCST_PWRGD.
 

2informaticos

Administrator
Staff member
Check diode mode to ground at PLT_RESET_L.
Remove U2071, R2071/81 and check if still low voltage.
If yes, you may have a PCH issue.
 
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