820-00138 fan start, no chime, no display

raainxx

Member
Hi,
this board is clean no liquid spill, the customer say, the mac make beep memory after an install system.
Now I have just fan spin, no chime and no display. i make this measure:
PPBUS_G3H 12.8v
SMC_ADAPTER_EN 3.38v
PM_BATLOW_L 3.3v
ALL_SYS_PWRGD 3.38v
PM_DSW_PWRGD 3,4v
PM_MEM_PWRGD 0,8V???
PCH_DSWVRMEN 3.23v
PM_SLP_SUS_L 3.34v
PPVCC_S0_CPU = 1,7V
SYS_PWROK_R=3,4V
PLT_RESET_L=0V
PLT_RST_BUF_L=0
PLT_RESET_L & PLT_RST_BUF_L & PM_MEM_PWRGD seems not good no?
thanks
 

2informaticos

Administrator
Staff member
Calculating R0620/21 resistor divider, PM_MEM_PWRGD looks good.

What about PM_PCH_PWROK and PM_PCH_SYS_PWROK?
 

raainxx

Member
PM_PCH_SYS_PWROK = 3,41V
i don't find the signal PM_PCH_PWROK because my board file is not the same like 820-00138 board.
do you have the good brd file? where can find it? on vinafix is not good.
thanks
 

2informaticos

Administrator
Staff member
Not real schematic/boardview files for this board; only 00163 available.

"i don't find the signal PM_PCH_PWROK"
Only one 0 ohm resistor present on pin 5/U1950; no boardview needed.
Just check if that resistor is good.

What about CPU_VCCST_PWRGD?
 

raainxx

Member
PM_PCH_PWROK = U1950/pin 5 = 3,4V R1947 is good 0ohm

XDP_CPU_VCCST_PWRGD = 0V on R1800, maybe U1930 but can't find it
PP1V05_S0_CPU_VCCST = 1,05V
 

raainxx

Member
CPU_PWRGD = 0V, PP1V05_S0_CPU_VCCST=1,05V, CPU_VCCST_PWRGD= 0V
U1100 is dead?
i don't understand if it's U1100 who make the CPU_PWRGD signal or U1930 for CPU_VCCST_PWRGD.
can i jump R1800 to 1,05V?
 

raainxx

Member
i check with this board for help but U1930 is unmount (i verify on a donor board, no component on U1930)
I can't find R1930 :-(
 
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