bahlaivlad
New member
Hello everyone! Glad to be a part of repair community. Hope to get some help.
I got a MacBook Air M2 (A2681), which I personally bought for repair. I spent some time trying to repair this laptop, so I will try to describe it in details.
Laptop sustained heavy corrosion of touchpad and battery connectors. Battery is damaged and dead (one bank was shorted by liquid and swollen). Display connector and motherboard are surprisingly clean and do not have any signs corrosion (except touchpad and battery connectors). No previous repair attempts were done to this board.
Initial state:
After cleaning all corrosion MB consumed 5V/0.4-0.2A in a loop, constantly trying to turn itself on, but failing. The display backlight flashed like a flashlight (for a moment) during this loop.
Discovered that UP700 IC (part of display backlight circuit) was faulty on 1V25 line and caused power IC to power cycle. After UP700 replacement the MB successfully switches to 20V, but current stuck at around 0.08A (80 mA). No fluctuation, just stable consumption, nothing heats up, except the M2 SoC (up to 40 C, not much). When connected to battery, the battery is charging. All required power lines and voltages are OK. After restoring touchpad and battery connectors diode measurements on them seems to be OK. Tried to connect it to another laptop to see if it's in DFU, but no.
I forced DFU mode (both keyboard and FORCE_DFU methods work) and the board boots to DFU, but Revive or Restore ends with an error (I connected MLB to known good battery and trackpad+ keyboard). During DFU Revive or Restore the laptop shows Apple logo for a minute or so, but then the logo disappears, no progress bar was shown (the backlight remains turned on though) and then Apple Configurator throws an error (4041 during Revive, 4014 during Restore):
I tried different cables, computers, but nothing helped. Being in desperate I changed MPMU U8100 and SPMU U7700 from known good board, but nothing changed as well (I thought there may be some internal damage to PMU). Finally, I replaced the NAND from another iCloud locked donor board.
After NAND replacement (current state):
Now the board still fails to Revive/Restore, but its behaviour is slightly different. Both Revive and Restore now returns error 9 instead of 4014/4041. And the progress bar now is shown during Revive/Restore process.
When doing Restore, it will just show Apple logo with a progress bar, but then the image disappears, backlight stays on and error 9 is returned.
When doing Revive, it will show Apple logo with a progress bar, it fills about 10% and then the image disappears, backlight stays on and error 9 is returned.
Now the board is stuck in DFU mode (all voltages seems to be present and stable).
So right now I am out of ideas. I have a couple of questions:
1. What to try next?
2. Is the CPU alive or not, can we assume it now? Basically, does it look repairable?
3. How fried touchpad/battery connectors may lead to such consequences?
I will be very grateful for any help.
I got a MacBook Air M2 (A2681), which I personally bought for repair. I spent some time trying to repair this laptop, so I will try to describe it in details.
Laptop sustained heavy corrosion of touchpad and battery connectors. Battery is damaged and dead (one bank was shorted by liquid and swollen). Display connector and motherboard are surprisingly clean and do not have any signs corrosion (except touchpad and battery connectors). No previous repair attempts were done to this board.
Initial state:
After cleaning all corrosion MB consumed 5V/0.4-0.2A in a loop, constantly trying to turn itself on, but failing. The display backlight flashed like a flashlight (for a moment) during this loop.
Discovered that UP700 IC (part of display backlight circuit) was faulty on 1V25 line and caused power IC to power cycle. After UP700 replacement the MB successfully switches to 20V, but current stuck at around 0.08A (80 mA). No fluctuation, just stable consumption, nothing heats up, except the M2 SoC (up to 40 C, not much). When connected to battery, the battery is charging. All required power lines and voltages are OK. After restoring touchpad and battery connectors diode measurements on them seems to be OK. Tried to connect it to another laptop to see if it's in DFU, but no.
AON Voltages:
PP1V8_AON - 1V8, OK
PP1V8_AON_MPMU - 1V8, OK
PP1V2_AON_MPMU - 1V25, OK
LDO:
PP1V5_LDOINT_MPMU - 1v5, OK
PPVDD_LDO20_14_8_3 - 1V28, OK
PP3V3_S2_LDO - 3V2, OK
S2:
PP1V2_S2_CIO - OK
PP1V05_S2SW_VDD2H - 1V02, OK
PP0V855_S2SW_CIO - 0V85, OK
PP1V25_S2 - 1V28, OK
PP1V8_S2 - 1V8, OK
P3V3S2_PWR_EN_MPMU - 1V8, OK
PP1V8_S2SW - 1V8, OK
AWAKE:
PP1V2_AWAKE_PLL - 1V2, OK
PP1V25_AWAKE_IO - 1V25, OK
PP1V8_AWAKE - 1V8, OK
PP5V_MPMPU_BSTLQ - 5V, OK
PMU_ONOFF_R_L - 1V65
MPMU_FAULT_OUT_L - 1V65
MPMU_SCRASH_L - 1V65V
PMU_CLK32K_SOC_R - OK, has signal
PMU_ONOFF_L - 1V8
IPD_LID_OPEN_1V8 - 1V8, OK
IPD_PWR_EN - 1V8
PMU_SYS_ALIVE - 1V28
NAND Voltages:
PP2V58_AWAKE_NAND_VCC - 2V5, OK
PP1V25_AWAKE_NAND_VCCQ - 1V26, OK
PP1V2_NAND0_S5E1_AVDD1X_PLL - 0V
NAND0_CLK24M_1 - OK, has signal
NAND0_RESET_L - 1V25, OK
PP0V88_AWAKE_NAND_VDD - 0V88, OK
NAND0_LPB_L - 1V26, OK
PP1V8_AON - 1V8, OK
PP1V8_AON_MPMU - 1V8, OK
PP1V2_AON_MPMU - 1V25, OK
LDO:
PP1V5_LDOINT_MPMU - 1v5, OK
PPVDD_LDO20_14_8_3 - 1V28, OK
PP3V3_S2_LDO - 3V2, OK
S2:
PP1V2_S2_CIO - OK
PP1V05_S2SW_VDD2H - 1V02, OK
PP0V855_S2SW_CIO - 0V85, OK
PP1V25_S2 - 1V28, OK
PP1V8_S2 - 1V8, OK
P3V3S2_PWR_EN_MPMU - 1V8, OK
PP1V8_S2SW - 1V8, OK
AWAKE:
PP1V2_AWAKE_PLL - 1V2, OK
PP1V25_AWAKE_IO - 1V25, OK
PP1V8_AWAKE - 1V8, OK
PP5V_MPMPU_BSTLQ - 5V, OK
PMU_ONOFF_R_L - 1V65
MPMU_FAULT_OUT_L - 1V65
MPMU_SCRASH_L - 1V65V
PMU_CLK32K_SOC_R - OK, has signal
PMU_ONOFF_L - 1V8
IPD_LID_OPEN_1V8 - 1V8, OK
IPD_PWR_EN - 1V8
PMU_SYS_ALIVE - 1V28
NAND Voltages:
PP2V58_AWAKE_NAND_VCC - 2V5, OK
PP1V25_AWAKE_NAND_VCCQ - 1V26, OK
PP1V2_NAND0_S5E1_AVDD1X_PLL - 0V
NAND0_CLK24M_1 - OK, has signal
NAND0_RESET_L - 1V25, OK
PP0V88_AWAKE_NAND_VDD - 0V88, OK
NAND0_LPB_L - 1V26, OK
I forced DFU mode (both keyboard and FORCE_DFU methods work) and the board boots to DFU, but Revive or Restore ends with an error (I connected MLB to known good battery and trackpad+ keyboard). During DFU Revive or Restore the laptop shows Apple logo for a minute or so, but then the logo disappears, no progress bar was shown (the backlight remains turned on though) and then Apple Configurator throws an error (4041 during Revive, 4014 during Restore):
I tried different cables, computers, but nothing helped. Being in desperate I changed MPMU U8100 and SPMU U7700 from known good board, but nothing changed as well (I thought there may be some internal damage to PMU). Finally, I replaced the NAND from another iCloud locked donor board.
After NAND replacement (current state):
Now the board still fails to Revive/Restore, but its behaviour is slightly different. Both Revive and Restore now returns error 9 instead of 4014/4041. And the progress bar now is shown during Revive/Restore process.
When doing Restore, it will just show Apple logo with a progress bar, but then the image disappears, backlight stays on and error 9 is returned.
When doing Revive, it will show Apple logo with a progress bar, it fills about 10% and then the image disappears, backlight stays on and error 9 is returned.
Now the board is stuck in DFU mode (all voltages seems to be present and stable).
So right now I am out of ideas. I have a couple of questions:
1. What to try next?
2. Is the CPU alive or not, can we assume it now? Basically, does it look repairable?
3. How fried touchpad/battery connectors may lead to such consequences?
I will be very grateful for any help.
FU remaining-cycles:1] -> [state:Recovery remaining-cycles:0] -> [state:RestoreOS remaining-cycles:0 (current state)]