820-3023-A no boot

[Sr. Robot]

Hi, got an 820-3023-A that was running slow when the battery was connected.

It had some previous issues that were fixed:

1. 3 beeps no boot: RAM reball solved it
2. Corossion on LCD connector and U9310: both cleaned and replaced.

Then it ran slow when the battery was connected (w or w/0 charger). Tried different batteries same thing. Without battery it ran fine.

Then suddenly Q7260 exploded. I replaced it but now its not booting (i have green light but no fan spin).

PPBUS_G3H:8.4v

PP3V42_G3H: 3.3v

PPDCIN_G3H: 17v

PP5V_S5: 5.0v

PP5V_SUS: 0v

PP3V3_S3: 0v

 

[2informaticos]

Diode mode to ground at L7260?
Do you get any voltage there?

 

[Sr. Robot]

Diode mode 0.293

P3V3S5_LLis 5v

P3V3S5_DRVL is 0v

 

[2informaticos]

Check all components related with L/Q7260 and corresponding side of U7201.
Post U7201 voltages; pins 23, 22, 12, 13, 29, 21.

 

[Sr. Robot]

23 = 8.4v
22 = 3.3v
12 = 3.3v
13 = 2.0v
29 = 5.0v
21 = 3.4v

 

[2informaticos]

Do you get L7260 voltage, or not?
If not, replace U7201.

 

[Sr. Robot]

i get voltage from L7260

 

[2informaticos]

Wasting two days to get a reply.
I wouldn't ask you for last checkings if you reply in time...

Do you get 3V3_SUS?

 

[Sr. Robot]

no PP3V3_SUS

 

[2informaticos]

No short there, missing PM_SLP_SUS_L too?

Check PM_BATLOW_L, SMC_ADAPTER_EN, PM_DSW_PWRGD, PCH_DSWVRMEN, PM_RSMRST_L, PM_PWRBTN_L and the 4 PCH's RTC signals.
Trigger SMC_ONOFF_L and check for drop pulse at PM_PWRBTN_L (at same time).

 

[Sr. Robot]

PM_SLP_SUS_L = 3.0v

PM_BATLOW_L= 0v

PM_DSW_PWRGD = 3.4v

PCH_DSWVRMEN = 3.1v

PM_RSMRST_L = 0v

PM_PWRBTN_L = 3.4v

RTC_RESET_L = 3.3v

PPVRTC_G3H = 3.3v

PCH_SRTCRST_L = 3.3v

SYSCLK_CLK32K_RTC = 0.4v

PM_PWRBTN_L pulses

 

[2informaticos]

I can't understand how peoples can still forget 2 of PCH's RTC signals; thousand times mentioned on the forum.

However, in this case seems to have a problem with Q7820/22.

 

[Sr. Robot]

I replaced Q7820, Q7822 and Q7840, D2400 just in case, but no change.

P3V3SUS_SS = 3.2v
P3V3SUS_EN_L = 3.3v
P5VSUS_EN_L = 4.8v

PCH_INTRUDER_L = 2.98 v
PCH_INTVRMEN = 3.2v

 

[2informaticos]

I didn't say to replace the transistors!

Post U7940 voltages.

 

[Sr. Robot]

SMC_BATLOW_L = 0v

SMC_BATLOW_L = 0.5v

PP3V3_S5 = 3.3v

PM_SLP_SUS_L = 3.3v

 

[2informaticos]

So missing SMC_BATLOW_L and PM_BATLOW_L.
PCH will not start power on sequence in this case.
Are you sure PM_SLP_SUS_L is high?

Try known good original Magsafe charger.
If still same, change SMC.