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MacBook Pro A1707 Not turning on, no shorts repair

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Revision as of 15:32, 29 October 2023 by ASRepairs (talk | contribs) (Created page with "{{stub}} {{Repair Guide |Device= |Affects parts= |Needs equipment= |Type= |Difficulty= }} ==Problem description== <nowiki>#</nowiki>incomplete Provide a concise description of the issue here. Be as specific as possible to help readers quickly determine whether or not this is the exact problem they are facing. thumb|Example image (Figure 1) -- No image yet. Help expand this page by uploading it! ==Symptoms== *Not turning on *Drawing 0A (no...")
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MacBook Pro A1707 Not turning on, no shorts repair
Device
Affects part(s)
Needs equipment
Difficulty
Type


Problem description

#incomplete

Provide a concise description of the issue here. Be as specific as possible to help readers quickly determine whether or not this is the exact problem they are facing.

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

Symptoms

  • Not turning on
  • Drawing 0A (no current) on 20V as measured by USB-C meter

Solution

Check for low resistance to ground on SMBUS_SMC_5_G3H_SDA or SMBUS_SMC_5_G3H_SCL

On older MacBooks, this would result in no battery recognition and a lower voltage on PPBUS_G3H—on USB-C models, it actually results in the machine not turning on at all. Can be caused by a tiny speck of conductive material in the battery connector.

Check for 0.4 V in diode mode on SMBUS_SMC_5_G3H_SDA and SMBUS_SMC_5_G3H_SCL (red probe on GND)

if it's higher the I2C signals will look funny, not going just between 0 and 3.3 V. Check D6950—it can be blown when the SMC goes.

Check voltage on PPBUS_G3H

If you have no or low voltage on this rail, check the repair steps below.

Repair Steps

low resistance to ground on SMBUS_SMC_5_G3H_SDA or SMBUS_SMC_5_G3H_SCL

Clean the conductive material, Video

0.4 V in diode mode on SMBUS_SMC_5_G3H_SDA and SMBUS_SMC_5_G3H_SCL (red probe on GND)

#incomplete

Low or no voltage on PPBUS_G3H

It could be bad/dead ISL9239. Also check for ≈2.4 Ω on the two ISL9239 current-sensing circuits. If any of the 1 Ω or current-sensing resistors are blown, replace them first, or you will re-kill any new ISL9239 you try!