A2992 - 5V - 0.00A - No Power

[applejuice95]

820-02918 - 2023 M3 A2992
- 5V 0.00A on Meter - USB-C
- No light on MagSafe

Small corrosion on UR730, and CR765 - Cleaned and scrubbed with ISP

Re-assembled. Tested, and computer worked, battery charged. Today after replacing a new USB-C I/o board, the machine no longer works.. We realized this was the wrong part, it was a port for A2442/A2485. The M3 uses a new part 821-04548-A.

After this, now computer has no power.


-PPBUs_AON = 0.00V
-PP3v8 = 0.00V
- PPDCIN_AON (F5600) - 5V


No DFU mode.

[mon2]

Remove all power. Meter in resistance mode. Measure the resistance to ground of PPBUS_AON. What is the exact resistance?

[applejuice95]

Measuring at C5253 & C5254 - 135ohms same thing near C9803

[mon2]

Connect the power adapter. Carefully measure the voltage to ground of:

PPCHGR_VDDA
PPCHGR_VDDP

SMBUS_BATT_SCL
SMBUS_BATT_SDA

[applejuice95]

PPCHGR_VDDA - 4.46 V
PPCHGR_VDDP - 4.416 V

SMBUS_BATT_SCL - 0.0V
SMBUS_BATT_SDA - 0.0V

(board is out of machine, on bench)

[mon2]

Remove all power. Measure the resistance to ground of PP1V8_S2. What is the resistance?

PP1V8_S2 is the LDO output created by the UF400 PD controller.

[applejuice95]

1.4Kohm

[mon2]

No short here.

With no power to the board what is the resistance to ground of PP3V8_AON?

Not sure on which PD controller is active for the port under use.

Test if you have a voltage output at:

PP3V3_UPC1_LDO (UF500)
PP1V8_UPC1_LDO (UF500)
PP1V5_UPC1_LDO_CORE (UF500)

PP3V3_UPC0_LDO (UF400)
PP1V8_UPC0_LDO (UF400)
PP1V5_UPC0_LDO_CORE (UF400)

For the active USB-C port, the local PD controller linked to that USB-C connector will offer the above LDO rails otherwise something is wrong.

Based on the earlier posts, you are missing the 1v8 rail required for the I2C communication with the buck / boost regulator for PPBUS_AON.

[applejuice95]

Thanks Mon, checking on Monday. we are closing out for the weekend. Thank you for all of your help, talk later.

[applejuice95]

PP3V8_AON - Resistance to Ground = 400ohms (starts around 100, builds up, stabilizes at 400).

(With Power cable in USB-C port #2) These are the voltages for UF500

PP3V3_UPC1_LDO (UF500) - 3.23V
PP1V8_UPC1_LDO (UF500) - 0.00V
PP1V5_UPC1_LDO_CORE (UF500) - 1.5V

Yes it would seem 1.8V rail is absent. 1.8V rail is also absent when power is moved to USB-C port #1 (just right of the MagSafe) - 3.3V is present on UF400, but 1.8V is not.

Checking for resistance to ground with power removed,
PP1v8_AON on C2221 - 23kOhms
PP1V8_S2 - 14kOhms
PP1V8_AWAKE - 4kOhms

[mon2]

Test for the PP1V5_UPCx_LDO_CORE rails on each PD controllers which feeds the BMC interface used by the CCx lines to select the 20v.

[applejuice95]

- The 3 USB-C PDs
PP1V5_UPC0_LDO_CORE - 1.5V
PP1V5_UPC1_LDO_CORE - 1.5V
PP1V5_UPC2_LDO_CORE - 1.5V

- The MagSafe
PP1V5_UPC5_LDO_CORE - 1.5V