View source for How To Fix a MacBook Pro A1706 Stuck on 5V and boot looping

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{{Repair Guide
|Device=MacBook Pro A1706
|Affects parts=Main Logic Board
|Needs equipment=Soldering Iron, Hot Air Station, Flux, Microscope, Tweezers
|Type=Soldering
|Difficulty=3. Hard
}}
== Problem description ==
A MacBook Pro A1706 (13-inch, Touch Bar) presents 5V and power cycling '''only on USB-C''' after liquid exposure near the '''CD3215 USB-C controller''' area.

On inspection, '''resistors near the CD3215 IC''' are found '''corroded''', interrupting the communication and power negotiation process between the logic board and the charger.
[[File:A1706-resistors.png|thumb|MacBook Pro - A1706 Corroded Resistor near CD3215]]

== Symptoms ==

* MacBook does not power on.
* USB-C meter shows 5V only, no negotiation to 20V.
* Visible corrosion around CD3215 IC.
* USB-C meter power cycles.

=== Diagnostic Steps ===

# '''Visual Inspection'''

* Examine both '''left and right CD3215 controllers''' near the USB-C ports.
* Look for '''corrosion, green residue, or burnt resistors''' in the '''LDO / CC line''' areas.


'''2. USB-C Meter Test'''

* Connect charger → verify if voltage negotiates to '''20 V'''.

* If it stays at '''5 V''', the CD3215 cannot communicate with the SMC or is missing key pull-ups.


3. '''Resistance Check'''

* Probe resistors connected to:

** '''CC1 / CC2 lines'''
** '''LDO_1V1 / LDO_1V8'''
** '''SCL / SDA communication lines'''

* If any resistor reads '''OL (open)''' or drastically higher resistance, replace it.


4. '''Communication Check'''

* Inspect the LDO '''resistors (typically 1 MΩ)''' next to the CD3215 IC.
* If corroded, CD3215 cannot detect the charger and initiate PD handshake.

== Repair Steps ==

# '''Clean the Area'''

* Remove conformal coating and corrosion with IPA and soft brush.
* If pads are damaged, repair traces under microscope.

2. '''Replace Faulty Resistors'''

* Identify corroded resistors (commonly '''R3108–R3109''' or nearby on CD3215 lines).
* Replace with correct values per schematic (typically 1 '''MΩ''' depending on the line).

3. '''Inspect Capacitors'''

* Check small caps near LDO and CC lines for shorts. Replace if leaky.

4. '''Reflow / Replace CD3215 (if needed)'''

* If corrosion extends under the CD3215 IC, reflow or replace it after cleaning pads thoroughly.

5. '''Test USB-C Negotiation'''

* Reconnect charger — voltage should rise to '''20 V / ~0.6 A–0.8 A''', indicating successful handshake.