Macbook Air 820-000165 missing PM_SLP_S5_L



Have a macbook air here that came in with no boot issue.

After check all power rails I get to PM_SLP_S5_L and we are at 0V

I tried SMC bypass though nothing happen, at best I see the fan move less then 1mm and stop, it's only really slight.

PM_CLK32K_SUSCLK_L = 3.257v
PM_PWRBTN_L = 3.4v

With the bypass not working are there other rails I can check to get to the bottom of this!



Staff member
"PM_SLP_S4_L is consistently changing - hangs around 500mA"
Might this be a typo?
I don't understand what you've meant.
How do you measure current for a signal???

If fan tries to spin, is sign of 5V_S0 pulsing.
Did you only note this in SMC bypass mode?

PM_SLP_S3_L should pulse each time you trigger SMC_ONOFF_L; confirm that.
ALL_SYS_PWRGD should also pulse, as big coils too.
Inspect U1950 area; check for pulse at its pins 7 & 3.
Just in case, remove Q8150, is not really needed.

Check for short on all big coils and after Power FETs (page 58).


Sorry mate, you're right, - "PM_SLP_S4_L is consistently changing - hangs around 500mA" is wrong - I get 0v

When I mention the fan, I wouldn't call it spin, it's ever so slightly budging.

"Inspect U1950 area; check for pulse at its pins 7 & 3."

When I trigger SMC_ONOFF_L I get a pulse at 7, nothing on pin 3

Checked for shorts, nothing.


Sorry I ignore you mention on the coils.

I checked L7310/20 for pulse, nothing.

I then checked diode reading on CPUVR_PHASE1 and I get 0.000 - full short.

So my question is, does that mean CPU is toast on this on, or what should I do next.

Thanks, Max


Thank s a lot for your help,

I removed the coils - Short on PPVCC_SO_CPU_PH1

Removed R7320/10 short on PPVCC_S0_CPU & CPU_VCCSENSE_P

Removed C7260 Cap still short on CPU_VCCSENSE_P

What can I do next or is this CPU gone?