Macbook Pro A1706 820-00239 No power, No liquid

[calamaro]

Hi to all guys, like I wrote in the title my macbook has no power problem.
It happened suddenly when I tried to power it on. I inspected the board, obviously no signs of liquid, corrosion or some burned cap. After a bit of troubleshooting I found the component U7800 runs very hot after 4/5 seconds after I connect the plug and it continues to run hot until I remove the plug.
I'm quite sure it could be a short circuit in that component and I ordered it but it will arrive in a month. Is there anything else I could test to be sure there are no other problems? How do you think about the problem?

Here are some measurements:

PP3V0_G3H = starts from 300mV and goes down to 278mV
PPVCC_S0_CPU = 0V
PP0V6_S0_DDRVTT = 0V
PP1V8_S0 = 0V
PP1V2_S0SW = 0V
PP1V0_S0SW = 0V
PP5V_S0_T139 = starts form 115mV and goes down
PP5V_S0 = 100mV
PP3V3_S0 = 0V
SMC_PM_G2_EN = 3.4V
PM_PCH_PWROK = 0V
PP3V3_PMICLDO = 3.3V
PPBUS_PMIC = 13.08V
CPU_VCCST_PWRGD = 0V
S5_PWRGD = 78mV
SMC_DELAYED_PWRGD = 0V
ALL_SYS_PWRGD = 0V

Thank you

[piernov]

Re: Macbook Pro A1706 820-00239 No power, No liquid

The PMIC can get hot due to it being bad, or due to a short to ground on one of the power rail it generates. So you have to take resistance to ground measurements on the power rail generated by the PMIC to confirm they are not shorted to ground.

[calamaro]

Re: Macbook Pro A1706 820-00239 No power, No liquid

The PMIC can get hot due to it being bad, or due to a short to ground on one of the power rail it generates. So you have to take resistance to ground measurements on the power rail generated by the PMIC to confirm they are not shorted to ground.

Thank you piernov for your reply!! I've found the short is on the PP5V_PMICLDO line where I have 2 caps (You find it on the page 78 of the schematic). How could I check which one is broken?

[calamaro]

Re: Macbook Pro A1706 820-00239 No power, No liquid

Update: I tried to remove a capacitor with hot air gun starting from 220ºC to 305ºC and with Chip Quik SMD291 Flux but I can’t even move it. What’s the problem? Wrong temperature, flux or what?

[calamaro]

Re: Macbook Pro A1706 820-00239 No power, No liquid

Found the bad cap. It was a nightmare desolder it. I used the hot air gun at 450°C with the flux, I removed it but the lead on both sides was never really melt. Fingers crossed when I have to place the new one.

[calamaro]

Re: Macbook Pro A1706 820-00239 No power, No liquid

Hi guys, I replaced the bad cap and now the U7800 is not running hot anymore but the board doesn't work. I have an usb tester where I see 20V but 0/0.03 A.
PP5V_PMICLD is 5V, PP3V3_PMICLDO is 3.3V.

Do you have any suggestion on how to proceed? Which check I should do?

[Pgratis]

Re: Macbook Pro A1706 820-00239 No power, No liquid

Hi,

Do you have a microscope?

You should take a close look on the area around where you have replaced the cap.

Having a flow of hot air around that area might have moved other components (even on the other side of the logic board).

Did you took any measurements on the power rails?
With your multimeter in diode mode to see if you have connection to the ground on the power rails.

BR,
PMA

[calamaro]

Re: Macbook Pro A1706 820-00239 No power, No liquid

Hi,

Do you have a microscope?

You should take a close look on the area around where you have replaced the cap.

Having a flow of hot air around that area might have moved other components (even on the other side of the logic board).

Did you took any measurements on the power rails?
With your multimeter in diode mode to see if you have connection to the ground on the power rails.

BR,
PMA

Thank you so much for your support! No components were moved (I found my hot air station doesn't work so well so I soldered the new cap with the solder).

I found that power rail PP5V_S0 is about 75mV and PP3V3_S0 is 0V. Could you help me to understand where they are generated?

Thank you

[disorder]

Re: Macbook Pro A1706 820-00239 No power, No liquid

first check if these lines are short to ground too.

[calamaro]

Re: Macbook Pro A1706 820-00239 No power, No liquid

first check if these lines are short to ground too.

Thank you for your reply disorder. Already checked in diode mode and they are not shorted to ground.

[disorder]

Re: Macbook Pro A1706 820-00239 No power, No liquid

check u8209
check pp5v_s4 and pp5v_so_en

[shibu]

Re: Macbook Pro A1706 820-00239 No power, No liquid

hi unplug j9600 then try

[calamaro]

Re: Macbook Pro A1706 820-00239 No power, No liquid

hi unplug j9600 then try

I have no problem with PPBUS_G3H so why I should unplug j9600?
I have no pp5v_s4 but pp5v_so_en is ok.

[calamaro]

Re: Macbook Pro A1706 820-00239 No power, No liquid

check u8209
check pp5v_s4 and pp5v_so_en

PP5V_S4 is about 28mV, PP5V_SO_EN is 0V, both are NOT shorted to ground (checked in diode mode)


I'm not sure but the problem could be here. PP5V_S4 and P5VS4_EN are not shorted to ground

[disorder]

Re: Macbook Pro A1706 820-00239 No power, No liquid

not sure can you check voltage on R7100 at both sides;
so actually you have to find why you don't have pp5V_s4, you haven't PP5V_S0 cause PP5V_S4 is not active

[calamaro]

Re: Macbook Pro A1706 820-00239 No power, No liquid

not sure can you check voltage on R7100 at both sides;
so actually you have to find why you don't have pp5V_s4, you haven't PP5V_S0 cause PP5V_S4 is not active

Thank you for your reply disorder. Voltage on R7100 is 0V. I don't understand on schematic where PP5V_S4 is generated. Isn't generated from U7650?

[calamaro]

Re: Macbook Pro A1706 820-00239 No power, No liquid

Thank you for your reply disorder. Voltage on R7100 is 0V. I don't understand on schematic where PP5V_S4 is generated. Isn't generated from U7650?

I'm sorry but I made a mistake, the voltage on R7100 is 28mV on both sides.

I made another measure on cap C7609 (you can find it in the image I uploaded before, on the right side of the U7600). On pin1 I have 4.8V and on pin2 28mV. I put the multimeter in diode mode and pin2 is ok but on pin1 I have 0L. I think this cap doesn't work well. Could you confirm?

Thank you

[calamaro]

Re: Macbook Pro A1706 820-00239 No power, No liquid

I'm sorry but I made a mistake, the voltage on R7100 is 28mV on both sides.

I made another measure on cap C7609 (you can find it in the image I uploaded before, on the right side of the U7600). On pin1 I have 4.8V and on pin2 28mV. I put the multimeter in diode mode and pin2 is ok but on pin1 I have 0L. I think this cap doesn't work well. Could you confirm?

Thank you

The cap C7609 is ok. Is it possible U7600 is dead?
A this point I have:

- PP5V_S4 = 28mV
- P5VS4_VBST = 4.8V
- P5VS4_EN = 174mV

- PP3V3_S5 = 0V
- P3V3S5_VBST = 4.8V
- P3V3S5_EN = 3.4V

pin4 of U7600 = 28mV
pin4 of U7660 = 0V

[Eddieno93]

Re: Macbook Pro A1706 820-00239 No power, No liquid

Hi guys, i have a problem with board 820-00239-A (no liquid damage). In short was U8000. After change still no power on but charging. I try change U7800 but still doesn’t work. Here is all result:

3V3_G3H - 3,3V
PPBUS_G3H - 13,05V
PP3V0_G3H - 3,078V
PP3V3_S0 - 0V
PP3V3_G3H - 3,404V
PP3V3_SUS - 3,352V
PP3V3_S5 - 3,354V
SMC_DELAYED_PWRGD - 0V
CPU_VCCST_PWRGD - 0V
SMC_ONOFF_L - 3,4V
RTC_RESET_L - 3V
ALL_SYS_PWRGD - 0V
S5_PWRGD - 3,265V
PLT_RST_L - 0V
PCH_INTRUDER_L - 3,078V
PCH_SRTCRST_L - 3,057V
PPVCCPRIMCORE_SUS_PCH - 1V
PM_PCH_PWROK - 0V
PM_PCH_SYS_PWROK - 0V
PM_SLP_S5_L - 0V 100kO to GND (R1454)
PM_PWRBTN_L 3,3V
PM_RSMRST_L - 3,351V
PM_BATLOW_L - 3,335V
PM_DSW_PWRGD - 3,4V
PM_SLP_SUS_L - 3,354V
PM_SLP_S0_L - 3,352V
PM_SLP_S3_L - 0V
PM_SLP_S4_L - 0V
PM_SLP_S5_L - 0V
PM_SLP_S0S3_L - 0V

PPBUS_HS_CPU - 13,04V
PPBUS_HS_OTH5V - 13,04V
PPBUS_HS_OTH3V3 - 13,04V
PPBUS_S4_HS_TPAD - 13,05V
PPBUS_PMIC - 13,06V
PP5V_S5 - 5,01V
P5VS4_PGOOD - 0V R7801 100kOhm and diode 0,425V
S5_PWRGD - 0V, R7802 85,5kOhm and diode 0,456V

After change U7650 S5_PWRGD is still 0V but now R7802 is 100kOhm.

Any suggestions?

[mr_xam]

Re: Macbook Pro A1706 820-00239 No power, No liquid

Hi, did you repaired it?