Hi. Recently serviced a damaged A1466 Macbook Air. Thought to post the issues and resolution for each.
Macbook AIR Model A1466 Diagnostic 09-01-2021
Issue: Liquid damaged (beer spill) Macbook AIR will not power up.
Problems & Resolutions
1) Attached Apple magsafe power adapter. No green / no orange light. This confirms the absence of the PP3V42_G3H voltage rail. The PP3V42_G3H rail is the primary voltage rail necessary to communicate with the magsafe power adapter to report the green or orange light status to the end user.
2) Logic board inside this A1466 chassis is 820-00165.
3) U7090 (LT3470) regulator was not generating the PP3V42_G3H voltage rail.
4) D7005 dual-anode diode (battery / power adapter selector) was confirmed to have no voltages on pins 1, 2 and 3.
5) J3000 connector was confirmed to receive approximately 15vdc from the magsafe power adapter on pins 1&2. This voltage mates to mosfet Q7010 pin 5. No voltage was output @ Q7010 pin 1.
6) DCIN_ISOL_GATE = 15vdc (same as the raw magsafe voltage).
7) For Q7010 to close and pass through the voltage onto pin #1, the gate must be a lower voltage than pin # 5. Confirmed that pin #5 = same voltage as gate so the mosfet remains OFF.
8) Sourced and replaced the 0201 footprint SMD 6v8 zener diode @ D7012.
9) With this replacement, gate is now about 6v5 and Q7010 enables to pass through the magsafe voltage rail onto D7005, pin # 1. D7005 then is able to pass through this adapter voltage to U7090.
10) U7090 still will not generate the required primary PP3V42_G3H voltage rail.
11) Corrosion was observed around U7090. Applied flux and reflowed U7090 DFN device. After this rework, the PP3V42_G3H enabled and allowed for a fan spin = typical and normal boot process for Macbooks.
12) Attached LCD display to the logic board. Power up Apple chime could be heard but no display can be seen.
13) Applied a flashlight onto edges of the LCD display to check on the status of the display. Can see the Apple logo graphics. This confirms the display is working but backlight is not.
14) Checked backlight voltage @ PPHV_S0SW_LCDBKLT = 0v. U7701 (backlight IC) fluxed & reflowed.
15) Checked fuse F7700 (SMD 0603 @ 32V; 3A) and it is blown.
16) Sourced and replaced F7700 – fuse blew again.
17) Replaced F7700 and removed the LCD display upon next power up. PPHV_S0SW_LCDBKLT = ~25V which is normal for the backlight for this display.
18) Attached the LCD display, fuse blew again.
19) Checked on the LVDS blade connector from the display and it has liquid damage / corrosion and a slight burn mark on the backlight pins (right side of the connector pins). Checked the resistance on these pins = about 9 ohms to ground which is too low.
20) Suspecting a defective LVDS cable. Sourced and replaced the LVDS cable. Confirmed that the resistance to ground is much higher and no longer 9 ohms. Applied a fresh fuse again with the new LVDS cable in place. LCD screen powers up properly with a valid backlight.
Watch parts 1 & 2 here:
https://www.youtube.com/watch?v=BkOAFSlfBTc
21) Macbook is starting to boot but has a corrupt SSD. Backed up critical files and reflashed with a new OS. Macbook is booting normally but keyboard and trackpad are not functional.
22) Liquid damage to the trackpad cable to the logic board which is also responsible for the keyboard interaction. The trackpad cable has corrosion and also some of the FFC cable contacts are broken and not allowing for all signals to pass through.
When replacing the trackpad cable - be sure that the replacement cable is with the same # of contacts & same pitch (distance between each contact) otherwise will cause more damage !!! We had a valid replacement trackpad cable in the shop for this model.
23) The trackpad cable is replaced and the keyboard & trackpad are now confirmed to be operational.
Summary:
Zener (D7012) blown & was replaced
Corrosion under U7090. Fluxed and reflowed 2 times to restore PP3V42_G3H rail.
LCD backlight = 0V. U7701 fluxed and reflowed.
SMD (0603 size) Fuse F7700 – replaced 3 times. Issue was due to very low resistance on the backlight LEDs for the LVDS display. The LVDS blade connector had extensive liquid damage and caused the backlight contacts to be brittle and discolored. The LCD display was taken apart and the LVDS cable was replaced.
Keyboard & trackpad did not work – internal trackpad cable was found to be defective due to liquid damage. This cable was replaced. Both keyboard & trackpad functions were restored.
SSD was partially corrupted. Installed a fresh OS to restore. Unit is repaired, is stable and has been confirmed to charge and operate from the original battery.
Macbook AIR Model A1466 Diagnostic 09-01-2021
Issue: Liquid damaged (beer spill) Macbook AIR will not power up.
Problems & Resolutions
1) Attached Apple magsafe power adapter. No green / no orange light. This confirms the absence of the PP3V42_G3H voltage rail. The PP3V42_G3H rail is the primary voltage rail necessary to communicate with the magsafe power adapter to report the green or orange light status to the end user.
2) Logic board inside this A1466 chassis is 820-00165.
3) U7090 (LT3470) regulator was not generating the PP3V42_G3H voltage rail.
4) D7005 dual-anode diode (battery / power adapter selector) was confirmed to have no voltages on pins 1, 2 and 3.
5) J3000 connector was confirmed to receive approximately 15vdc from the magsafe power adapter on pins 1&2. This voltage mates to mosfet Q7010 pin 5. No voltage was output @ Q7010 pin 1.
6) DCIN_ISOL_GATE = 15vdc (same as the raw magsafe voltage).
7) For Q7010 to close and pass through the voltage onto pin #1, the gate must be a lower voltage than pin # 5. Confirmed that pin #5 = same voltage as gate so the mosfet remains OFF.
8) Sourced and replaced the 0201 footprint SMD 6v8 zener diode @ D7012.
9) With this replacement, gate is now about 6v5 and Q7010 enables to pass through the magsafe voltage rail onto D7005, pin # 1. D7005 then is able to pass through this adapter voltage to U7090.
10) U7090 still will not generate the required primary PP3V42_G3H voltage rail.
11) Corrosion was observed around U7090. Applied flux and reflowed U7090 DFN device. After this rework, the PP3V42_G3H enabled and allowed for a fan spin = typical and normal boot process for Macbooks.
12) Attached LCD display to the logic board. Power up Apple chime could be heard but no display can be seen.
13) Applied a flashlight onto edges of the LCD display to check on the status of the display. Can see the Apple logo graphics. This confirms the display is working but backlight is not.
14) Checked backlight voltage @ PPHV_S0SW_LCDBKLT = 0v. U7701 (backlight IC) fluxed & reflowed.
15) Checked fuse F7700 (SMD 0603 @ 32V; 3A) and it is blown.
16) Sourced and replaced F7700 – fuse blew again.
17) Replaced F7700 and removed the LCD display upon next power up. PPHV_S0SW_LCDBKLT = ~25V which is normal for the backlight for this display.
18) Attached the LCD display, fuse blew again.
19) Checked on the LVDS blade connector from the display and it has liquid damage / corrosion and a slight burn mark on the backlight pins (right side of the connector pins). Checked the resistance on these pins = about 9 ohms to ground which is too low.
20) Suspecting a defective LVDS cable. Sourced and replaced the LVDS cable. Confirmed that the resistance to ground is much higher and no longer 9 ohms. Applied a fresh fuse again with the new LVDS cable in place. LCD screen powers up properly with a valid backlight.
Watch parts 1 & 2 here:
https://www.youtube.com/watch?v=BkOAFSlfBTc
21) Macbook is starting to boot but has a corrupt SSD. Backed up critical files and reflashed with a new OS. Macbook is booting normally but keyboard and trackpad are not functional.
22) Liquid damage to the trackpad cable to the logic board which is also responsible for the keyboard interaction. The trackpad cable has corrosion and also some of the FFC cable contacts are broken and not allowing for all signals to pass through.
When replacing the trackpad cable - be sure that the replacement cable is with the same # of contacts & same pitch (distance between each contact) otherwise will cause more damage !!! We had a valid replacement trackpad cable in the shop for this model.
23) The trackpad cable is replaced and the keyboard & trackpad are now confirmed to be operational.
Summary:
Zener (D7012) blown & was replaced
Corrosion under U7090. Fluxed and reflowed 2 times to restore PP3V42_G3H rail.
LCD backlight = 0V. U7701 fluxed and reflowed.
SMD (0603 size) Fuse F7700 – replaced 3 times. Issue was due to very low resistance on the backlight LEDs for the LVDS display. The LVDS blade connector had extensive liquid damage and caused the backlight contacts to be brittle and discolored. The LCD display was taken apart and the LVDS cable was replaced.
Keyboard & trackpad did not work – internal trackpad cable was found to be defective due to liquid damage. This cable was replaced. Both keyboard & trackpad functions were restored.
SSD was partially corrupted. Installed a fresh OS to restore. Unit is repaired, is stable and has been confirmed to charge and operate from the original battery.
I've seen what this community can do, so I'm pretty sure you guys can help me out.