MacBook A2337 Touchpad and Keyboard Function Failure Repair

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MacBook A2337 Touchpad and Keyboard Function Failure Repair

Defect Phenomenon

The MacBook Air 2020 A2337 works normally, but on the second day, the touch bar and home button functions both failed.

Troubleshooting

Disassemble the phone and we find the flex cable connector of the touch bar with some problems

01 The little board with some problem

A part of the buckle on the connector is missing

02 Part of the buckle on the connector is missing

Put back a buckle under the microscope carefully

03 buckle replacement

After that, test again. The touch bar and keyboard functions are still not working. The issue should come from the motherboard

Take out the motherboard, and measure the diode value on the IPD B2B connector JT400#

04 IPD B2B

All the diode values are OK. 

Then connect with the DC power supply and measure the voltage values. After measuring, we find that pin 29# (PP5V_S2_IPD_F) voltage value is abnormal. 

Keep tracking the schematic, and we find the 5V voltage is provided by the UC840.

The basic working conditions for the UC840 including power and enable

  • PP5V_S2
  • P5V_S2SW_IPD_EN
After measuring, the 5V voltage (PP5V_S2) is OK. However, the ENABLE signal (P5V_S2SW_IPD_EN) is not OK. The voltage value on this rail should be 1.8V, but there is no voltage.
05 The enable and power
 

So we should keep tracking the enable signal, after searching the schematic. The signal is outputted from the chip UC870

06 UC870

Measure the basic working conditions of the UC870,

  • P5VS2_PWR_EN
  • IPD_PWR_EN 

07 UC870 working conditions

All values are OK.

So there is a high chance, that the touchpad and keyboard issue should be caused by the UC870 being damaged.

Find this chip on the motherboard and replace it with a new one

09 A2337 Touch Pad and

After replacing, and measuring the voltage value on the chip UC840 again, the voltage value on the ENABLE signal (P5V_S2SW_IPD_EN) is back to normal.

Then assemble the MacBook and test again, both the touch bar and keyboard function back to normal.

A2337

Summary

The A2337 touchpad and keyboard function failure issue get fixed by UC870 (IPD_PWR_EN Gating Logic) replacement.

MacBook A2337 Touchpad and Keyboard Function Failure Repair

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REWA Academy

As an enthusiastic educator and expert in mobile technology, REWA Academy has dedicated its career to empowering individuals through technical education. With a keen focus on cellphone repairs, they have developed comprehensive online and offline courses at REWA Academy. Their expertise spans a wide array of areas, including iPhone repair training, phone hardware, software, and advanced troubleshooting techniques. Through their writings, they aim to demystify mobile technology complexities, making it accessible and understandable for both novices and professionals in the field.

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