#1 Apple MacBook Pro A1278 Parade chip stays hot during sleep, MB after spillage
przez Cubytus • 4 stycznia 2016, 18:50
Hi there,
here's my updated topic with additional information.
Failure description:
I got a water-damaged MBP where an unknown chip (probably related to Thunderbolt and HDMI functions) stays active and hot during sleep. The battery discharges much faster than it would do otherwise, and so deeply that time and date settings are lost and reset to 2008 when the main battery can no longer provide enough juice. Having the wrong date means certificates are not recognized as valid, and prevent wireless connection.
Chip that stays hot is circled in red (this isn't my picture!):
PCB marking codes:
820-2936-B
Already attempted:
According to the only shop that does this kind of repair in this city, replacing the burned chip is just too dangerous for the computer to be worth it, on an otherwise working machine. It's a 40-pin QFN package, very close to other tiny components as shown in the picture. Another repair shop does it across the border, but asks $400 for it, with no guarantee it will work. I don't have the tools or skills myself to attempt this repair.
A hardware test was performed at an official Apple Store, and it didn't reveal any malfunction. That leads me to think the problem is probably low-level.
One possible solution
On computers that don't have a removable main battery and no button cell battery, there's often a supercapacitor holding CMOS and RTC data.
The other option would be to replace this supercapacitor powering the MBP A1278 by a standard 3V battery to power the PRAM and SMC, and add a physical switch to disconnect the main battery while hibernating. Sounds like a less risky alternative as only two solder points on the board would be required.
Questions
The question would be: where is the supercap holding the charge for the PRAM and SMC on a Late 2011 MBP?
Or, what other solutions would be feasible on this computer?
here's my updated topic with additional information.
Failure description:
I got a water-damaged MBP where an unknown chip (probably related to Thunderbolt and HDMI functions) stays active and hot during sleep. The battery discharges much faster than it would do otherwise, and so deeply that time and date settings are lost and reset to 2008 when the main battery can no longer provide enough juice. Having the wrong date means certificates are not recognized as valid, and prevent wireless connection.
Chip that stays hot is circled in red (this isn't my picture!):
PCB marking codes:
820-2936-B
Already attempted:
According to the only shop that does this kind of repair in this city, replacing the burned chip is just too dangerous for the computer to be worth it, on an otherwise working machine. It's a 40-pin QFN package, very close to other tiny components as shown in the picture. Another repair shop does it across the border, but asks $400 for it, with no guarantee it will work. I don't have the tools or skills myself to attempt this repair.
A hardware test was performed at an official Apple Store, and it didn't reveal any malfunction. That leads me to think the problem is probably low-level.
One possible solution
On computers that don't have a removable main battery and no button cell battery, there's often a supercapacitor holding CMOS and RTC data.
The other option would be to replace this supercapacitor powering the MBP A1278 by a standard 3V battery to power the PRAM and SMC, and add a physical switch to disconnect the main battery while hibernating. Sounds like a less risky alternative as only two solder points on the board would be required.
Questions
The question would be: where is the supercap holding the charge for the PRAM and SMC on a Late 2011 MBP?
Or, what other solutions would be feasible on this computer?
