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Dead, No Charging Light - MacBook Air 13" 2013 A1466, 820-3437

Posted by eFix Ltd on

In this case study, we have a MacBook Air 13" 2013 A1466 model (board number 820-3437) which is completely dead, and not showing an orange or green charging light, using a known good charger.

Whenever an older MacBook is not showing a charging light, this means there is either an issue with communication between the charger and the SMC, or a power issue, where certain voltages are either not present, or not making it to where they need to go.

Disassembling the device, there were no obvious signs of a spillage. Measuring voltages on the board, we could see a main voltage, PP3V42_G3H, was around 1V instead of 3.42V. This voltage is responsible for powering a number of chips on the logic board, some of which are responsible for producing the charging light, and since it was too low it was not providing enough power to turn on chips such as the SMC, ISL6259A and other components required for the boot up process.

Inspecting the logic board, we could see that there was visible corrosion around U7090, which we cleaned using our ultrasonic cleaner. After the clean, this voltage was still low, and although U7090 was receiving it's input voltage of 18.5V, it was not outputting PP3V42_G3H at the correct amount of 3.42V.

Liquid Damage Around U7090 Area

This pointed to an issue with LT3470AED (U7090), so our first course of action was replacing this chip to restore PP3V42_G3H. Luckily, after replacement, PP3V42_G3H was now outputting at the correct voltage of 3.42V, and the MacBook was powering on. It was also now producing the correct charging light when the charger was plugged in, and we have successfully fixed their 820-3437 logic board which was showing no charging light, and was not booting.

In this case, the area affected was at the top edge of the board, right by the vent opening. There were signs of a very small spillage on the logic board itself in this area, and the PP3V42_G3H regulator area was the only area affected by this damage. The customer was made aware of this and remembered they spilt a small drop of water on the MacBook 3 months prior to the MacBook failing and refusing to boot or charge, on this occasion the damage did not affect the MacBook instantly.

If your MacBook Air A1466 is not showing a charging light and is not booting, it likely has an issue related to the logic board, similar to this device. Feel free to book it for our free liquid recovery service and we can find out what is causing the issue, and offer the relevant repair.


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