ALB-Repairs
Member
Hi - Im new here, but not to the world of macbook board repair. Done hundreds.
This machine is stumping me though. The symptoms the machine came in with were 'Keyboard and trackpad only work intermittently' This apparently occurred after storage for several months. The laptop and motherboard are clean, and show no signs of liquid ingress.
they explained that for the most part the keyboard seemed to work, they had fitted a new trackpad, when i received it i noticed the 'no movement but click works' symptom. There is no 18v5 boost on these machines.
I tested all voltages to the trackpad and keyboard controller, I tested another trackpad to no avail.
Digging deeper i tested all the passive components that are anything to do with the keyboard and trackpads function, i found no issues, Im talking about all capacitors and resistors. I tested every trace for continuity. Eventually i decided to change the keyboard controller IC. Being a programmed IC i was worried that it wouldn't function, The design elements for the keyboard and trackpad support matched up between this machine and the 820-3332.
Upon completing the work i re-tested the machine to find the keyboard option keys/power keys/ SMC reset keys working to allow boot menu and perform other basic functions. In OSX we now have a slightly different fault. The keyboard doesn't work at all, nor does the trackpad.
Scratching my head and thinking thats strange, probably slightly different programming on the 820-3332 keyboard controller, i order two scrap 820-3787 donor boards. Once they arrived i replaced the keyboard controller again, this time sure that i have the correct controller, with the correct programming.
The symptoms are once more exactly the same.
Ive read up that people have experienced this issue and its down the the SPI firmware, I found a good dump for the EFI, and wrote over the dirty ME region with the boards original ME region, reflashing with the known dump. Same results once more.
This has lead me to think there are a couple of possibilities.
Could i have a damaged USB section on my PCH- This is an incredibly long shot but the PCH has no real protection for the USB data-lines, can i rule this out as for the most part they seem to communicate (with the keyboard at certain points of this repair working)?.
Could the communication between the KBC and the PCH somewhat depend on parts of the ME region of the SPI. Should i clean the SPI dump i have with a fresh ME region and hope for the best?
My main concern is that with the original keyboard controller i had keyboard function in OSX for the most part, This could be a red herring because the customer stated that sometimes in OSX the keyboard completely stops responding.
Sorry this is probably a lot of poorly written bable to take in without any real measurements or part numbers. If anyone can shine a light at the right pathway i would be very grateful. More odd issues and complex posts to follow, I hope this is the right forum for me.
This machine is stumping me though. The symptoms the machine came in with were 'Keyboard and trackpad only work intermittently' This apparently occurred after storage for several months. The laptop and motherboard are clean, and show no signs of liquid ingress.
they explained that for the most part the keyboard seemed to work, they had fitted a new trackpad, when i received it i noticed the 'no movement but click works' symptom. There is no 18v5 boost on these machines.
I tested all voltages to the trackpad and keyboard controller, I tested another trackpad to no avail.
Digging deeper i tested all the passive components that are anything to do with the keyboard and trackpads function, i found no issues, Im talking about all capacitors and resistors. I tested every trace for continuity. Eventually i decided to change the keyboard controller IC. Being a programmed IC i was worried that it wouldn't function, The design elements for the keyboard and trackpad support matched up between this machine and the 820-3332.
Upon completing the work i re-tested the machine to find the keyboard option keys/power keys/ SMC reset keys working to allow boot menu and perform other basic functions. In OSX we now have a slightly different fault. The keyboard doesn't work at all, nor does the trackpad.
Scratching my head and thinking thats strange, probably slightly different programming on the 820-3332 keyboard controller, i order two scrap 820-3787 donor boards. Once they arrived i replaced the keyboard controller again, this time sure that i have the correct controller, with the correct programming.
The symptoms are once more exactly the same.
Ive read up that people have experienced this issue and its down the the SPI firmware, I found a good dump for the EFI, and wrote over the dirty ME region with the boards original ME region, reflashing with the known dump. Same results once more.
This has lead me to think there are a couple of possibilities.
Could i have a damaged USB section on my PCH- This is an incredibly long shot but the PCH has no real protection for the USB data-lines, can i rule this out as for the most part they seem to communicate (with the keyboard at certain points of this repair working)?.
Could the communication between the KBC and the PCH somewhat depend on parts of the ME region of the SPI. Should i clean the SPI dump i have with a fresh ME region and hope for the best?
My main concern is that with the original keyboard controller i had keyboard function in OSX for the most part, This could be a red herring because the customer stated that sometimes in OSX the keyboard completely stops responding.
Sorry this is probably a lot of poorly written bable to take in without any real measurements or part numbers. If anyone can shine a light at the right pathway i would be very grateful. More odd issues and complex posts to follow, I hope this is the right forum for me.
