macbook air 820-00165 don't want to go out

[madjid]

Hi,

the macbook air had no liquid damage but did not start at all, having checked the signals I replaced the smc, now the macbook starts perfectly the sound the ssd the battery everything works, the only problem is that 'it is impossible to turn it off, when I keep pressing the power button it turns off but restarts, whether with or without battery, or bare motherboard, do you have an idea? I couldn't find anything in the searches.

 

[2informaticos]

Check R1449/52, R1617/38.
Test the board disconnecting airport card and webcam.
Also test with known good trackpad flex/board.

 

[madjid]

R1449 84kohms
R1452 9,8komhs
R1617 96,5komhs
R1638 90,4kohms
Resistance ok and no short
I tested the motherboard
naked, with smc onoff, same result, turns off then restarts

 

[2informaticos]

I was expecting the voltage on the signals related with mentioned resistors.
In fact check any kind of WAKE signal.

Also measure the 4 RTC signals.

 

[madjid]

PCH_SRTCRST_L 3,34v
RTC_RESET_L 3,34v
PCH_INTRUDER_L 3,04v
PCH_INTVRMEN 3,23v
R1449 0,01v
R1452 3,34v
R1617 3,24v
R1638 0,02v
pp3v3_s5 3,35v
SMC_PME_S4_WAKE_L 3,42v
SMC_S4_WAKESRC_FR 0v
SMC_WAKE_L 3,3v
SMC_WAKE_L 3,3v
No short

 

[2informaticos]

Check pins 1 & 3 of U3560.

Did you solder SMC from donor 00165 board?
Should be good to try another one, just in case.

Be sure SMC_LSOC_RST_L and SMC_RESET_L stay high when pressing power button.
Machine still restarts if you turn it off by software (from macOS)?

 

[madjid]

U3560 pin 1 3,31v ; pin 3 3,35v
SMC from donor 00165 board yes
SMC_LSOC_RST_L 3,41v stay high witch press gnd/smc_onoff_L
SMC_RESET_L 3,375v; 3,95v witch press gnd/smc_onoff_L
with macos big sur, no he's not restarts if i turn it off by software, but won't start with power button

 

[2informaticos]

Can you start it triggering SMC_ONOFF_L, instead of using power button?

 

[madjid]

I soldered a wire to SMC_ONOFF_L to try but that doesn't work eithe.
same result with bypass smc

 

[2informaticos]

What is SMC_ONOFF_L voltage?
No reaction at all when trigger it?

 

[madjid]

turn off by the osx I can't do anything impossible to start you have to remove the battery charger to restart, witch SMC_ONOFF_L or power button same result, SMC_ONOFF_L 3,42; when i turn it off with SMC_ONOFF_L when os x is on the desktop, can't restart it either

 

[2informaticos]

Did you try to trigger SMC_ONOFF_L with trackpad flex disconnected?
Check SMC_LSOC_RST_L and be sure SMC_RESET_L is also steady, at same time.

 

[madjid]

with trackpad flex disconnected, shut down by osx, SMC_ONOFF_L don't restart and start
SMC_LSOC_RST_L 3,40v stable

 

[2informaticos]

So actually, machine only starts by itself when connect the charger?

Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L.
Did you try another SMC?

 

[madjid]

So actually, machine only starts by itself when connect the charger? = I can start it with SMC_ONOFF_L or the power button when it has not been turned off by osx

PM_PWRBTN_L 3,35 stable

it must be a smc problem I will try another one but I have few