got a macbook pro A1398 (820-3332-A) with an orange light on charger even battery is not connected. board is clean with no signs of liquid damage. upon checking for any short circuit via multimeter, at L7550/L7560 gives only 1ohms, and at L7510/L7520/L7530 gives only 0.9ohm. and if i set to Diode mode or continuity test at those points it gives a ZERO reading. most likely a damaged U1000?
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Last edited by salawayon; 05-30-2022, 06:28 AM. -
Re: Troubleshooting dead Apple MacBook Pro A1398 (820-00426-A)
Not enough info to draw that conclusion, but it is low. Usually if you have a shorted CPU, then one of the high side MOSFET's is shorted and PPBUS_G3H is also shorted to ground as a result. Often this is from an issue with the PWM driver IC (in this case U7400). This can be from liquid damage, or even the decomposing corpse of a dead bug next to that IC.
Do 1V voltage injection with thermal camera. You might be lucky and it's a shorted cap or low side MOSFET. -
Re: Troubleshooting dead Apple MacBook Pro A1398 (820-00426-A)
When it is warm, Ivy Bridge can measure close to 1 ohm.OpenBoardView — https://github.com/OpenBoardView/OpenBoardViewComment
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Apple MacBook Pro 15'' A1398 X435 051-00330 820-00138 Schematic & Board View
A1398 main board resistance measurements (user submitted no further details)...10-01-2024, 06:58 AM -
Hi everyone, I have a MacBook a1398 emc2910 with an 820-00426A motherboard.
I have a short on the "PPBUS_G3H" line... I traced it to the "U7310" IC
FDMF6808N"
and indeed the IC is shorted between "Vin and VSWH."
On the motherboard, Vin to ground = open and it's OK.
VSWH to ground = about 5,50 / 7.50 Ohms.
With this measured value, can I safely replace this IC or is the CPU compromised?
Do you have any other suggestions?
Thanks for any help you can give me.Today, 03:35 AM -
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Hi everyone!
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Apple MacBook Pro 15 Retina A1398 EMC2910 820-00426 Boardview...10-26-2024, 04:08 AM
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