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do you try on external display?

finally i check power sequence like this example G3H/RTC rails + 32kHz RTC clock → {SRTCRST, RTCRST, INTVRMEN, INTRUDER#, DSWVRMEN} → S5 rails → S5_PWRGD → DPWROK → SLP_SUS# → SUS rails → RSMRST# → BATLOW# → PWRBTN# → SLP_S5# → SLP_S4# Some signal are not present on this board. all seems good...

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...

ok i have no pulse on all PM_SLP_Sx_L. i think it's power sequence problem. I try to find it this day. i have a question for power supply, can i use a external power supply and apply 12V on the board? without the real supply because it's hard to check signal on the iMac. thanks

ok thanks for your help, it work well. i try to read other forum thread but i'm not already connected to read all.

PM_PWRBTN_L fall down when i push button. PM_RSMRST_PCH_L stay always high

no pulse PP12V_S0_FET & PM_SLP_S4_L when i push on the power button I check the signal SMC_ONOF_L fall down when i push the button.

Hi, i have this imac with only one led1 i find some component broken like R5335, U5420, U9720 (when i remove this last PP5V_S0 in diode mode 0,020 became 0,250) for the last i can't find the reference REF3333, is not the reference i think. i would like to find in other board but when i search...

sorry but i can't find it on the forum. do you have a link please? thanks

ok thanks, if i want disable discrete GPU is with medusa board? or another solution?

Hi, i have this board no liquid with this screen in attach file i have reflow U8900 but same problem, is it bad GPU? thanks

yes i read on just U3200, i change U3200 and now the mac work. Thanks for the chip firmware, i understand now for C00 & other.

In diode mode LDO_3V3= 0,008 LDO_1V8A= 0,511 LDO_1V8D=0,028 LDO_BMC=0,5

thanks for schematic and boardview. yes all 4 ports stay at 5V. i check in diode LDO output and post after. U3200 is hot when connect on all ports. if i need to change, can i take on another board, i haven't this board to pick this component.

Hi, i have this board 820-00850, the issue the usb-c input stay at 5V (0,200A->0,400A). i have PPBUS at 12,3V but cycling (9V to 12,3V) i haven't the board file, i use the board file to 820-01041 but it's not same. have you this file board? what can i check to same my problem? i have this chip...

i check all SPI resistors seems all good and trace too. I check with scope all the signals on U6100, all signal communicate but not on pin 3 & 7. is it normal? i change the bios with good bios same problem and i clean me of the original with cmizapper same.

I check all voltage on page 71/72, all pulse at the good voltage but after fall, some voltage don't fall at 0v. No short find on this voltage. Yes i keep the smc on other same board 3115.

sorry, i have 0V, no pulse. U2650 pin 4 PM_S0_PGOOD=0V no pulse U2660 pin 4 SYS_PWROK_R=0V no pulse

acowan the fan start normally and stop after 1second

R7402 = 150K R7403=182K L7330 = 1,5V and fall L7260 = 5V and fall L7220 = 3V3 always L7630 = 1V and fall L7100 =1V and fall L7550 = nothing L7510 = nothing L7520 = nothing SMC Bypass not work, same problem turn fan normally and shutdown