Hello,
I have a 2011 MacBook Pro 13" as described in the title, specifically an A1278 with the 820-2936B logic board.
It was sitting for a few years, I booted it up to make a backup and install fresh during which I noticed the 100% fans and 90C temps on the CPU so, as I usually do, I opened it to refresh the thermal paste on the CPU and give it a good clean on the exhaust side.
It wasn't easy to get the board out, and it actually ripped a bit of the black insulation that is covering the backside of the keyboard, around where the CPU is. That's fine, there's no traces there, I believe.
I removed the well cooked thermal paste, cleaned both cpu and heatsink properly with alcohol, applied some fresh mx4 and proceeded to reassemble everything.
Now it does not boot at all, I had all lights on the battery level meter and a green light on the charger but nothing on fans or screen when pressing the power button. My first thought... I killed the button. Still, I decided to let it rest as it was late and I was tired.
The next day I connected the charger, still a green light, but nothing on the battery meter, so I disassembled the logic board and started watching videos about these repairs. I do have some electronics experience, but I'm a coder, so this is pretty much out of my league, however that has never stopped me before, so I started testing things at random.
I find no shorts, the battery is pretty much shot, when powering it with the battery I get a single flashing led, when powering without the battery but with the meter I get all flashing leds, so at least that part of the circuit seems to be working fine. Voltages on the battery connector without a battery are:
P4 - SMBUS_SMC_BSA_SCL - 3.4v
P5 - SYS_DETECT_L - 0v
P6 - SMBUS_SMC_BSA_SDA - 3.4v
P7..P9 - PPVBAT_G3H_CONN - 12.57v (but every few seconds starts dropping and jumps back to 12.57, I assume as part of the charging circuitry)
When connecting a battery, all the same except P7 to P9 are on the 100mv range.
Connecting the charger never spins the fan at all, which is something other macs seem to do for a little while when being powered, even without anything else connected on the board.
This battery was holding a charge for a few minutes at least before I opened the laptop, so my first assumption would be something shorted on the charging circuit, but then the laptop does not boot without a battery connected, so I feel I need a helping hand in "debugging" this one.
I have checked some ICs along the way, and there's 12.57v on PPBUS_S5_HS_OTHER_ISNS, but that's about it.
Any ideas on what to check? I do not have a donor board to start replacing components, and honestly this is more of a learning exercise than anything else, as I could just buy a working logic board to replace this for much less that what the time I have already put into this would net me on my daily work, but hey, if I can fix this I will definitely feel like it was worth the time! I like learning new things.
I have a 2011 MacBook Pro 13" as described in the title, specifically an A1278 with the 820-2936B logic board.
It was sitting for a few years, I booted it up to make a backup and install fresh during which I noticed the 100% fans and 90C temps on the CPU so, as I usually do, I opened it to refresh the thermal paste on the CPU and give it a good clean on the exhaust side.
It wasn't easy to get the board out, and it actually ripped a bit of the black insulation that is covering the backside of the keyboard, around where the CPU is. That's fine, there's no traces there, I believe.
I removed the well cooked thermal paste, cleaned both cpu and heatsink properly with alcohol, applied some fresh mx4 and proceeded to reassemble everything.
Now it does not boot at all, I had all lights on the battery level meter and a green light on the charger but nothing on fans or screen when pressing the power button. My first thought... I killed the button. Still, I decided to let it rest as it was late and I was tired.
The next day I connected the charger, still a green light, but nothing on the battery meter, so I disassembled the logic board and started watching videos about these repairs. I do have some electronics experience, but I'm a coder, so this is pretty much out of my league, however that has never stopped me before, so I started testing things at random.
I find no shorts, the battery is pretty much shot, when powering it with the battery I get a single flashing led, when powering without the battery but with the meter I get all flashing leds, so at least that part of the circuit seems to be working fine. Voltages on the battery connector without a battery are:
P4 - SMBUS_SMC_BSA_SCL - 3.4v
P5 - SYS_DETECT_L - 0v
P6 - SMBUS_SMC_BSA_SDA - 3.4v
P7..P9 - PPVBAT_G3H_CONN - 12.57v (but every few seconds starts dropping and jumps back to 12.57, I assume as part of the charging circuitry)
When connecting a battery, all the same except P7 to P9 are on the 100mv range.
Connecting the charger never spins the fan at all, which is something other macs seem to do for a little while when being powered, even without anything else connected on the board.
This battery was holding a charge for a few minutes at least before I opened the laptop, so my first assumption would be something shorted on the charging circuit, but then the laptop does not boot without a battery connected, so I feel I need a helping hand in "debugging" this one.
I have checked some ICs along the way, and there's 12.57v on PPBUS_S5_HS_OTHER_ISNS, but that's about it.
Any ideas on what to check? I do not have a donor board to start replacing components, and honestly this is more of a learning exercise than anything else, as I could just buy a working logic board to replace this for much less that what the time I have already put into this would net me on my daily work, but hey, if I can fix this I will definitely feel like it was worth the time! I like learning new things.
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