MacBook Pro A2338 Not turning on, 0.00 - 0.05A current draw at 5V repair

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MacBook Pro A2338 Not turning on, 0.00 - 0.05A current draw at 5V repair
Device MacBook Pro A2338
Affects part(s) Motherboard
Needs equipment multimeter, soldering iron, soldering station
Difficulty ◉◉◉◌ Hard
Type Micro-Soldering"Micro-Soldering" is not in the list (Soldering, Teardown, Part replacement, Cleaning, Software, BGA, General) of allowed values for the "Repair Guide type" property., Part replacement


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Problem description

Facing an issue with the MacBook Pro A2338 displaying 5V and a very low current draw of 0.00 to 0.05A on the USB-C meter.

Symptoms

  • MacBook Pro A2338 stuck on 5V with a current draw of 0.00 to 0.05A on the USB-C meter.
  • Not turning on, all voltages missing.

Solution

Identifying the problem

Check for DFU or Recovery Mode

  • Connect the MacBook Pro A2338 to another Mac or MacBook via the master port (top left side USB-C port, closest to the display).
  • Use Apple Configurator 2 to verify whether the device is in DFU or recovery mode.
  • If the device is in DFU mode, proceed to "Device stuck in DFU mode due to corrupt firmware" in the repair steps below.

Check voltage on PPBUS_AON

  • Measure voltage on PPBUS_AON by placing your multimeter in DC mode, black probe on ground, and red probe on PPBUS_AON. A suitable measuring point on the 820-02020 logic board is C5403 (Figure 1). Normal voltage should be around 12.60-13.1V.
  • If the voltage is approximately 12.28-12.35V, it may indicate a communication issue between the SOC and PMICs, or corrupt firmware.
  • If the voltage is 0V, proceed to the repair steps for shorted or absent PPBUS_AON voltage.

Check PP3v8_AON voltage

  • PP3v8_AON voltage may vary depending on the device's sleep state.
  • To check voltage on PP3v8_AON, set your multimeter to DC mode, black probe on ground, and red probe on PP3v8_AON. Measuring points include L5800, L5820, or L5840 (Figure 2) under the larger black shield sticker on the top side of the system board. Normal voltage should be around 3.8V.
  • If voltage is missing or low, proceed to the repair steps for PP3v8_AON low or missing.

Check PP3v3_S2 voltage

  • To check voltage on PP3v3_S2, set your multimeter to voltage mode, place one lead on ground and the other lead on PP3v3_S2 LC710 (Figure 3) is a suitable measuring point. Normal voltage should be around 3.3V.
  • If PP3v3_S2 is missing, proceed to the repair steps for PP3v3_S2 low, missing, or shorted to ground.

Check CD3217 support voltages

  • Measure the following support voltages for CD3217 (Figure 4):
  1. - PP5v_S2: Normal voltage ≈ 5V measuring point: LC320 (Figure 5).
  2. - PP3v3_S2_UPC: Normal voltage ≈ 3.3V measuring point: C8303 (Figure 6).
  3. - PP1v25_S2: Normal voltage ≈ 1.25V measuring point: Pin 2 of L77D0 (Figure 7).
  • If any of the S2 rails are missing, proceed to CD3217 support S2 rails low or missing repair steps below.
  • If all findings are negative, consider CD3217 or related circuit issues.

Note that voltage measurement should be performed WHILE the device is plugged in!

Solving the problem

Device stuck in DFU mode due to corrupt firmware

  • Revive firmware via Apple Configurator 2.
  • Ensure the MacBook is running the latest macOS version for consistent results.
  • Follow the provided Apple support article for the procedure.
  • Once plugged in, open Apple Configurator 2. You should see a big square icon pop up that says "DFU" or rarely, "RECOVERY". Click the icon, Navigate to the top menu bar click "Actions" then "Advanced". Select Revive device. You will see a progress bar appear. This process can take over 30 minutes in some cases as Apple Configurator 2 now reinstalls the OS in addition to the M1's firmware. Data will still be retained with the revive option.
  • Be cautious that selecting "Restore" will wipe all user data.
  • Possible causes for a device to fail a DFU revive include various hardware issues listed above.

How to find short circuits

PPBUS_AON shorted, low or absent

  • Inject around 1V with a 5A limit into PPBUS_AON using a DC power supply.
  • Perform thermal imaging of the board or apply isopropyl alcohol to locate the shorted component.
  • Replace the identified shorted component.

PP3v8_AON low or missing

  • Check for a short to ground on PP3v8_AON (normal diode mode to ground reading ≈ 0.350).
  • If a short to ground is found, replace the shorted component.
  • Check the enable signal to U5700 (Figure 8), P3V8_PWR_EN, and address any issues with U5340 (Figure 9) or surrounding components.
  • Ensure VIN (PPBUS_AON) is making it to U5700; if not, investigate possible broken traces or issues with RD550.
  • If the above findings are negative, replace U5700.

PP3v3_S2 low, missing, or shorted to ground

  • If PP3v3_S2 is missing with a short, find and replace the shorted component.
  • If PP3v3_S2 is missing without a short, replace UC710 (Figure 3).
  • If PP3v3_S2 is shorted to ground, find and replace the shorted component.

CD3217 support S2 rails low or missing

  • Check for shorts to ground or enable issues on the affected S2 rails.
  • Replace any shorted components or address enable issues as necessary.

CD3217 Diagnostic Process

  • There is no definitive diagnostic test for a faulty CD3217 (Figure 4) other than replacing it.
  • Test 1: Measure PPDCIN_AON_CHGR_R on both ports to identify an internal MOSFET issue in one CD3217 (Figure 4).
  • Test 2: Measure the LDO outputs of both CD3217s to check if one is not outputting proper voltage; replace the corresponding CD3217 if found.
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