Macbook air 820-3437 and 820-00164 PP5V_S5 missing PM_SLP_S4_L on both boards

Soji

Member
I had to combine both logic boards issue in a thread, because they are some what similar. They have similar same issues, missing PM_SLP_S4.
PP5V_S5 is present
Signals that will make the PCH produce PM_SLP_S4_L are also present on both boards. 1.PPVRTC_G3H -3.3V
2. RTC_RESET_L 3.3V
3. PCH_SRTCRST_L 3.3V
4. PCH_INTVRMEN_L 3.3V
5. PCH_DSWVRMEN_L 3.3V
6. SYSCLK_CLK32K
7. PP3V3_S5 3.3V
8. PM_DSW_PWRGD 3.3V
9. PP3V3_SUS 3.3V
10. PM_BATLOW_L 3.3V
11. PM_RSMRST_L 3.3V.
Sometimes, PM_SLP_S4_L is intermittently present, but if I withdraw power and restore it, it goes missing again. I'd appreciate your input.
 

2informaticos

Administrator
Staff member
Please, do not mix the boards.
Same symptom doesn't imply the same cause.

When the PM_SLP_S4_L is high, which coils get voltage?
PM_SLP_S3_L goes high at same time?

Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L.
PM_SLP_S4/3_L should pulse at same time.
 

Soji

Member
Good day
You were right, I shouldn't have mixed board, I sincerely apologise for that. I also made a typo error, the first board was 820-3435-B.

For the macbook air 820-3435-B
-With Charger plugged in fan spins temporarily and stops.
-Triggered SMC_ONOFF_L , charger light changed from amber to green and back to amber, got a fan spin temporarily and PM_SLP_S4 went high temporarily. Both fan spin and PM_SLP_S4 occured simultaneously.
-As for the coils, I'm not sure what coils to check, pls can you specify for me what coils to check.


For the macbook air 820-00164-A
- With charger plugged in nothing happened
- Triggered SMC_ONOFF_L, there was no reaction at all
- I rechecked the those signals that will bring about PM_SLP_S4
PCH_INTVRMEN is 2.3V
PCH_DSWVRMEN was alsi 2.3V
PM_RSMRST_L was 3V they were not up to 3.3V
All other voltages was present and they were 3.3V
 

2informaticos

Administrator
Staff member
820-3435 board should restart two times, before stays on; like its 13" sister (3437).

Supposing that you've triggered SMC_ONOFF_L with R5115/16 pads (no keyboard connected), seems to have a problem with U5110, or its SMC_LSOC_RST_L input; check its level.

Open new thread for 00164 board.
Post there all the information mentioned above...
 

Soji

Member
Understood, will open another thread for 820-00164
Th SMC_LSOC_RST_L is high at 3.2V, I will check U5110
 

Soji

Member
Changed the u5110, the board comes on most of the times, let's say it comes on 7 times out of 10times, but during those times it does not come on if I trigger SMC_ONOFF_L it comes back on.
 

Soji

Member
Apologies, I don't understand what you mean, pls can you rephrase, "Check R5127, traces and solders"??
 

Soji

Member
R5127 is 0.4 ohm, which is approximately 0 ohm, there's good continuity from pin 2 of R5127 to pin 3 of u5110. Tried triggering SMC_ONOFF_L at R5115, there's fan spin and it stays on. But it does not stays on when charger plugged.
 

2informaticos

Administrator
Staff member
SMC_RESET_L MUST stay high when you press power button.
If drops but SMC_LSOC_RST_L stays high (no drop pulse at all), then the problem is around U5110.
 

Soji

Member
Good day 2informaticos
Still on this system
I changed the u5110.
It worked for a while and went back to where we started from.
If I trigger R5116/R5115 or R5101 the fan will just spin temporarily and stop.
 
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