Hi,
A customer brought in an A1989 logic board that is in a boot loop.
It chimes and the backlight flashes briefly and does it all over again. The CPU gets warm as do the SSD, U2800 and UB00. It let me rebuild bridge OS sucesfully in DFU mode with no change.
All USB ports get 20v and go up to 0.456ma and then down again in the loop.
The board is clean, there are no signs of liquid damage or corrosion. The customer said it just wouln't start one day for no reason.
Some of the voltages I checked are as follows:
PP3V3_G3H - 3.35v
PP5V_G3S - 5.12v
PVCCEDRAM_S0_REG_R - 0v
PPVCCGT_CPU_PH3 - 0v
PPVCCGT_CPU_PH2 - 0v
PPVCCGT_CPU_PH1 - 0v
PPVCC_CPU_PH1 - 0.656v
PPVCC_CPU_PH2 - 0.655v
PPVCCSA_CPU_R - 0.813v
PP0V95_S0_CPUVCCIO_REG_R - 0.953v
PP1V2_S3_REG_R - 1.2v
PPVIN_S0SW_LCDBKLT - 0.012v
P5VUSBC_T_R - 0v
P5VUSBC_X_R - 0v
PP0V9_SSD0 - 0.899v
PP1V8_SSD0 - 1.799v
PP2V7_NAND_SSD0 - 2.5v
ALL_SYS_PWRGD - 1.7v
Any advise would be a great help.
A customer brought in an A1989 logic board that is in a boot loop.
It chimes and the backlight flashes briefly and does it all over again. The CPU gets warm as do the SSD, U2800 and UB00. It let me rebuild bridge OS sucesfully in DFU mode with no change.
All USB ports get 20v and go up to 0.456ma and then down again in the loop.
The board is clean, there are no signs of liquid damage or corrosion. The customer said it just wouln't start one day for no reason.
Some of the voltages I checked are as follows:
PP3V3_G3H - 3.35v
PP5V_G3S - 5.12v
PVCCEDRAM_S0_REG_R - 0v
PPVCCGT_CPU_PH3 - 0v
PPVCCGT_CPU_PH2 - 0v
PPVCCGT_CPU_PH1 - 0v
PPVCC_CPU_PH1 - 0.656v
PPVCC_CPU_PH2 - 0.655v
PPVCCSA_CPU_R - 0.813v
PP0V95_S0_CPUVCCIO_REG_R - 0.953v
PP1V2_S3_REG_R - 1.2v
PPVIN_S0SW_LCDBKLT - 0.012v
P5VUSBC_T_R - 0v
P5VUSBC_X_R - 0v
PP0V9_SSD0 - 0.899v
PP1V8_SSD0 - 1.799v
PP2V7_NAND_SSD0 - 2.5v
ALL_SYS_PWRGD - 1.7v
Any advise would be a great help.