Macbook Pro Retina 820-4924. Pulsing PM_SLP_S4

Macbook Pro retina 820-4924

ISSUE:
  1. Pulsing PM_SLP_S4_L on DMM. from 0.02v to 2.9v and then 0.02v
  2. CPU/PCH internal voltage regulators 1.05V is pulsing on DMM.
  3. No fan Spin
Troubleshooting done:
Checked the following power rails. All of them have 3.3v as it should be and clock is OK.

Question:
Suspect a bad PCH/CPU??

PPVRTC_G3H3.3v
RTC_RESET_L3.3v
PCH_SRTCRST_L3.3v
PCH_INTVRMEN_L3.3v
PCH_DSWVRMEN_L3.3v
SYSCLK_CLK32K_RTCX132.76khz
PP3V3_S53.3v
PM_DSW_PWRGD3.3v
PP3V3_SUS3.3v
PM_BATLOW_L3.3v
PM_RSMRST_L3.3v
PM_PWRBTN_L3.3v
 
Last edited:

2informaticos

Administrator
Staff member
Check if PM_SLP_S3/0_L also pulse.
And check for pulse at all big coils too.

"No fan Spin"
Not relevant on this board for diagnose; fan starts very late, when CPU gets really hot.

Any history available?
PCH_RESET_L pulses?
 
Thanks 2informaticos: See following pls.
  1. PM_SLP_S3 = PULSES
  2. PM_SLP_S0 = PULSES AS WELL.
  3. PCH_SRTCRST= 3.3V
  4. PLT_RST = 0V
Bad PCH/CPU?

No history unfortunately on this one.
 

2informaticos

Administrator
Staff member
You should get pulse at all big coils then; maybe not CPU ones.
Check what happens at pins 7 & 3 of U1950.
 
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