820-02757: Not powering up on magsafe/usb-c except on battery

[repMacFixit]

Got this board, no sign of liquid damaged. The MagSafe light is off but once I plug in a usb-c it goes from 5v with some current draw to 20v but no current draw. This happens on both usb-c ports. The system ran while the battery still had charge. Suspecting the cd3217 chip for the MagSafe but wondering if there are anything else I can check. I’ve checked for shorts on all the components around the chip and all looks good. Also, like the A2442, does the chip have to be pulled from the same donor board and same position (I have a A2338 with the same usb-c chip or will a A2779 or A2780)?

Couple Measurements taken

PP3V3_UPC5_LDO: 3.4V
PP3V3_S2_LDO: 3.2V

 

[2informaticos]

CD3217 chips must come from same model donor board, maintaining the position also.

Compare diode mode readings around all them.
They switch to 20V if battery is disconnected?

The Magsafe light is controlled by charger, in base of the communication with the MacBook.
Do you get some voltages on the U5500 at least?

 

[repMacFixit]

Diode mode readings were comparable to a good board. What should the voltage on USBC5_CC1 be (unfortunately i no longer have the good board available)? Away, i'm getting 1.66v on USBC5_CC1.

And yes, when the battery is connected, the two usb-c ports did switch to 20V but no current draw.

 

[2informaticos]

Magsafe's CC1 voltage should be same as other ports CC1/2 lines, depending on the cable orientation.
BTW, Magsafe port uses only CC1, no CC2 line neded there.
1.66V looks good enough.

Anyway, on Magsafe case, there are more chips involved than USBC side.
What voltage do you get on PPBUS_AON and 3V8_AON in all cases?
Also check U8100 and U7700 LDOs.

 

[repMacFixit]

PPBUS_AON - 12.0V (Both MagSafe and usb-c)
PP3V8_AON - 3.796v (Both MagSafe and usb-c)

Not main LDO signals on U8100 and U7700
PP1V5_LDOINT_MPMU - 1.5V
PPVDD_LDO20_14_8_3 - 1.25v
PP3V3_S2_LDO - 3.3v

 

[2informaticos]

There are more LDOs for MPMU and you didn't post any SPMU LDO yet.

BTW, don't bother with "NC" marked ones.

 

[repMacFixit]

My mistake. i was looking for signal lines with LDO around those chips and not the actual port names. Anyway, here are the voltages collected using the MagSafe as power source.

PP1V2_AON_SPMU - 1.2V
PP1V5_LDOINT_SPMU - 1.5V
PP1V5_SPMU_VREFADC - 0.0v
PP1V8_AON_SPMU - 1.8v
PP3V8_AON_SPMU_ISNS_VIN - 3.79v
PP5V_SPMU_BSTLQ - 5.0v
PP1V25_S2 - 1.25v
PP0V88_S1 - 0.000v
PP1V8_S2 - 1.8v
PP0V8_S1_VDD_FIXED - 0.0v
PP0V72_S2_VDD_LOW - 0.75v


PP1V2_AON_MPMU - 1.2v
PP1V5_LDOINT_MPMU - 1.5v
PP1V5_MPMU_VREFADC - 0.0012v
PP1V8_AON_MPMU - 1.8v
PP3V8_AON_MPMU_ISNS_VIN - 3.8v
PPVDD_LDO20_14_8_3 - 1.25v
PPVDD_S2SW_VDD2H - 0.0v
PP1V8_AON - 1.8v
PP3V3_S2_LDO - 3.3v
PP1V2_AWAKE_PLL - 0.0v
PP3V3_AON - 3.3v
PP0V855_S2SW_CIO - 0.00v
PP3V3_S2SW_SNS - 0.0v
PP1V2_S2_CIO - 0.0v

 

[repMacFixit]

With USB-C

PP1V2_AON_SPMU - 1.2V
PP1V5_LDOINT_SPMU - 1.5V
PP1V5_SPMU_VREFADC - 0.0v
PP1V8_AON_SPMU - 1.8v
PP3V8_AON_SPMU_ISNS_VIN - 3.8V
PP1V25_S2 - 1.25v
PP0V88_S1 - 0.0v
PP1V8_S2 - 1.8v
PP0V8_S1_VDD_FIXED - 0.0v
PP0V72_S2_VDD_LOW - 0.75v

PP1V2_AON_MPMU - 1.2v
PP1V5_LDOINT_MPMU - 1.5v
PP1V5_MPMU_VREFADC - 0.0v
PP1V8_AON_MPMU - 1.8v
PP3V8_AON_MPMU_ISNS_VIN - 3.8v
PPVDD_LDO20_14_8_3 - 1.25v
PPVDD_S2SW_VDD2H - 0.0v
PP1V8_AON - 1.8v
PP3V3_S2_LDO - 3.3v
PP1V2_AWAKE_PLL - 0.0v
PP3V3_AON - 3.3v
PP0V855_S2SW_CIO - 0.00v
PP3V3_S2SW_SNS - 0.0v
PP1V2_S2_CIO - 0.0v

 

[2informaticos]

Check diode mode to ground on the lines with missing voltage.
Compare with working board.
If not the same model available, compare with a similar platform.

 

[repMacFixit]

Comparison bad board/Good Board (this board has iCloud lock but works)

PP1V5_SPMU_VREFADC - 0.593/0.590
PP0V88_S1 - 0.347/0.3528
PP0V8_S1_VDD_FIXED -0.298/0.300

PP1V5_MPMU_VREFADC - 0.587/0.5915
PPVDD_S2SW_VDD2H - 0.0546/0.06
PP1V2_AWAKE_PLL - 0.4274/0.4343
PP0V855_S2SW_CIO - 0.326/0.3319
PP3V3_S2SW_SNS - 0.5213/0.5226
PP1V2_S2_CIO - 0.4621/0.4739

 

[2informaticos]

Not big differences.

MPMU LDOs are in page 43 (LDO OUTPUTS).
PP1V5_MPMU_VREFADC isn't there.
Also, if PPVDD_LDO20_14_8_3 isn't present, you can't expect any LDO derived from it.
Only LDOs directly derived from 3V8_AON must appear in first moment.

PP0V88_S1 should appear later; so PP0V8_S1_VDD_FIXED is also delayed.

If any basic LDO (powered from 3V8_AON) is missing, then you may have problems with U8100, or U7700.