[SOLVED]820-3330 Brain dead... or zombie at least

[PJs]

820-3330 from A1286 2012

There is no picture (even on external screen) and no chime, but CPU and GPU warms up. It beeps without RAM, but that's the only sign of life. Will not start in SMC bypass mode, or after SMC reset - I've never seen it running. I tried to flash the BIOS chip with known good one (with clean ME) for 820-3330, but nothing changed (so I flashed back the old one). There were no signs of spills, oxidation or previous repairs. It looks to me like dead CPU? I've got one CPU for 820-3330 on stock, so I can change it, but I'm not sure if it's really dead when it still beeps without RAM... Also why would it die? The chip itself looks OK, like everything else on the motherboard.


PPVCORE_S0_CPU 1.11V
PPVCORE_GPU 0.90V
PPVCORE_S0_AXG 0V

PP3V42_G3H
PPBUS_G3H 12.53V
PPVRTC_G3H 3.33V

PP5V_S5 5.05V
PP5V_S3 5.05V
PP5V_S0 5.04V
PP3V3_S5 3.33V
PP3V3_S3 3.33V
PP3V3_S0 3.33V
PP1V5_S3 1.50V
PP1V2_S0 1.20V
PP1V05_S0 1.03V
PP0V75_S0_DDRVTT 0.74V

LCD_PWR_EN 0.00V
DP_MUX_EN 1.00V
CPU_PWRGD 1.02V
SMC_RESET_L 3.10V
ALL_SYS_PWRGD 3.29V
PM_SLP_S4_L 3.33V
SMC_LID 3.09V

SMC_CLK32K present
SYSCLK_CLK32K_RTC present

Thank you

 

[dukefawks]

Beeping without RAM means it is at least sort of alive. Is a USB mouse lighting up? PRAM reset with external keyboard done with everything else disconnected?

 

[PJs]

No, USB mouse is not lighting up, I tried both USB ports and 5V is there, but no light.

 

[dukefawks]

Ah, so there was an issue on CPU Vcore. I'm pretty sure the CPU was damaged when that happened RIP.

 

[PJs]

Yes, you are right, I changed the CPU and I did not fully test it yet, but it boots now So this one is solved, thanks