MacBook Pro A2338 Not turning on, current draw cycling between 0.00 and 0.45a at 5V repair and MacBook Pro A2338 Clicking sound from system board, showing 5v on USB-C amp meter repair: Difference between pages

From Repair Wiki
(Difference between pages)
No edit summary
 
(Created page with "{{Repair Guide |Device= |Affects parts= |Needs equipment= |Type= |Difficulty= }} {{stub}} ==Problem description== Clicking sound from the system board with 5V measured by the USB-C amp meter. ==Symptoms== *Clicking sound from the system board. *5V reading on the USB-C amp meter. ==Solution== ===Diagnostic Steps=== thumb|Example image (Figure 1) -- No image yet. Help expand this page by uploading it! ====Measure voltage on PP3v8_AON==== No...")
 
Line 1: Line 1:
{{Repair Guide
{{Repair Guide
|Device=MacBook Pro A2338
|Device=
|Affects parts=Motherboard
|Affects parts=
|Needs equipment=multimeter, soldering iron, soldering station
|Needs equipment=
|Type=Soldering, Micro-Soldering
|Type=
|Difficulty=3. Hard
|Difficulty=
}}
}}
{{stub}}
{{stub}}
==Problem description==
==Problem description==
MacBook Pro A2338 not turning on, showing only 5V on the USB-C meter, and cycling current draw between 0.00 and 0.45A.
Clicking sound from the system board with 5V measured by the USB-C amp meter.


== Symptoms==
==Symptoms==
*Not turning on, all voltages missing.
*Clicking sound from the system board.
*Not charging, only 5V on the USB-C input.
*5V reading on the USB-C amp meter.
*Pulling between 0.00-0.45A shown by USB-C ammeter.


== Solution==
==Solution==
===Diagnostic Steps===
===Diagnostic Steps===
[[File:Placeholder image.jpg|thumb|(Figure 1) -- No image yet. Help expand this page by uploading it!]]
[[File:Placeholder image.jpg|thumb|Example image (Figure 1) -- No image yet. Help expand this page by uploading it!]]
==== Checking for short to ground on a rail powered by a PMIC. PP1v8_S2====
====Measure voltage on PP3v8_AON====
Normal voltage = 3.8v. You will likely find that the voltage is low and pulsing slightly or completely absent. This confirms the diagnosis.


*''Missing information''
====Perform a visual inspection of the system board====
This failure is very uncommon without liquid damage. Often times, you will find that one of the 3v8_AON MOSFETs will be corroded, or that U5700 itself will be corroded. If the MOSFETs (Q5800, Q5820, or Q5840) are corroded, proceed to the Repair Steps below for "PP3v8_AON creation MOSFETs corroded" below. If the PP3v8_AON buck converter IC (U5700) is corroded, proceed to the "PP3v8_AON buck converter IC corroded" repair steps below.


==== Checking for short to ground on a rail produced by U7700 or U8100====
===Repair Steps===


*Check for shorts to ground on outputs of U8100 and U7701: [[How to find short circuits]]
====PP3v8_AON creation MOSFETs corroded====
*#L8100 / L8101 / L8102 (PPVDD_PCPU_AWAKE) (Figure 1) - Normal diode mode to ground reading ~0.007 / ~45Ω (Resistance)
*Replace Q5800, Q5820, and Q5840 together. It's important to replace all 3 MOSFETs at the same time as if one MOSFET failed, it may have damaged the others. Replacement of U5700 is not necessary as long as it isn't corroded and as long as the clicking sound does not persist after replacement of the MOSFETs.
*#L82B0 / L82B1 (PPVDD_ECPU_AWAKE) - Normal diode mode to ground reading ~0.114 / 140Ω (Resistance)
*#L8270 / L8271(PPVDD_CPU_SRAM_AWAKE) - Normal diode mode to ground reading ~ 0.116 / 450Ω (Resistance)
*#L8120 (PPVDD_SOC_S1) - Normal diode mode to ground reading ~ 0.012 / 110Ω (Resistance)
*#L8110 / L8111 / L8112 (PPVDD_GPU_AWAKE) - Normal diode mode to ground reading ~ 0.010 / 35Ω (Resistance)
*#L8280 / L8281 (PPVDD_DISP_S1) - Normal diode mode to ground reading ~ 0.055 / 233Ω (Resistance)
*#L8290 (PPVDD_DCS_S1) - Normal diode mode to ground reading ~ 0.176 / 310Ω (Resistance)
*#L84E0 - (PP1v4_LDO_PREREG) - Normal diode mode to ground reading ~ 0.285 / >30kΩ (Resistance)
 
===Repair Steps===
''High Resolution thermal imaging is highly specific for the detection of short circuits on M1 boards and should be the first line diagnostic method when short circuits are suspected.''


==== short to ground on a rail produced by U7700 or U8100====  
====PP3v8_AON buck converter IC corroded====
*Replace U5700. Replacement of the PP3v8_AON creation MOSFETs is not required unless they are corroded or if the clicking sound persists after replacement of U5700.


*Replace the shorted component
Verify correct voltage on PP3v8_AON after the relevant repair is performed.
**''Case Report from user: TCRS Circuit An 820-02020 presented with no power. Upon inspection, no diffuse signs of liquid damage were seen on the system board or enclosure components. Thermal imaging was performed which revealed abnormal pulsation and enhancement of U8100 and L8230 (PP1v8_S2). A short to ground was measured. 1v and 5 amps was injected to the line which revealed abnormal enhancement of UC820. (PP1v8_S2 to PP1v8_S2SW_VDD1 switch.) UC820 was replaced which restored 20v on the USB C amp meter, however amperage was still abnormal at 0.08 amps. Thermal imaging revealed some heating of the CPU when power was first connected. Further in depth visual inspection revealed C1105 to have signs of cracking and excessive heat. A short to ground was measured on PP1v8_S2SW_VDD1. C1105 was removed, with resolution of the short, however function was not fully restored, and PP1v8_S2SW_VDD1 was still seen to be missing despite normal VIN and EN lines to UC820. UC820 was replaced again which restored full function of the board. We can conclude that in this particular case, UC820 was likely damaged from overload due to a short on its output.''

Revision as of 17:48, 18 September 2023

MacBook Pro A2338 Clicking sound from system board, showing 5v on USB-C amp meter repair
Device
Affects part(s)
Needs equipment
Difficulty
Type


This article is a stub. You can help Repair Wiki grow by expanding it

Problem description

Clicking sound from the system board with 5V measured by the USB-C amp meter.

Symptoms

  • Clicking sound from the system board.
  • 5V reading on the USB-C amp meter.

Solution

Diagnostic Steps

Example image (Figure 1) -- No image yet. Help expand this page by uploading it!

Measure voltage on PP3v8_AON

Normal voltage = 3.8v. You will likely find that the voltage is low and pulsing slightly or completely absent. This confirms the diagnosis.

Perform a visual inspection of the system board

This failure is very uncommon without liquid damage. Often times, you will find that one of the 3v8_AON MOSFETs will be corroded, or that U5700 itself will be corroded. If the MOSFETs (Q5800, Q5820, or Q5840) are corroded, proceed to the Repair Steps below for "PP3v8_AON creation MOSFETs corroded" below. If the PP3v8_AON buck converter IC (U5700) is corroded, proceed to the "PP3v8_AON buck converter IC corroded" repair steps below.

Repair Steps

PP3v8_AON creation MOSFETs corroded

  • Replace Q5800, Q5820, and Q5840 together. It's important to replace all 3 MOSFETs at the same time as if one MOSFET failed, it may have damaged the others. Replacement of U5700 is not necessary as long as it isn't corroded and as long as the clicking sound does not persist after replacement of the MOSFETs.

PP3v8_AON buck converter IC corroded

  • Replace U5700. Replacement of the PP3v8_AON creation MOSFETs is not required unless they are corroded or if the clicking sound persists after replacement of U5700.

Verify correct voltage on PP3v8_AON after the relevant repair is performed.

Retrieved from "https://repair.wiki/index.php?title=MacBook_Pro_A2338_Not_turning_on,_current_draw_cycling_between_0.00_and_0.45a_at_5V_repair&oldid=113"