820-4924 no trackpad and keyboard

No-Clean

Member
Clean board, sometimes when the battery is disconnected and connected again trackpad and keyboard works fine for a few hours or days, but it always comes back with no trackpad and keyboard.

Board is perfect.
 

2informaticos

Administrator
Staff member
Does this only happens once logged in?
Check if you can access boot menu always.

Try known good trackpad board/flex.
Be aware of new chinese cables, many bad.
 

No-Clean

Member
Thanks, when it happens even at login screen no trackpad and keyboard and no boot menu option.

So if the trackpad cable goes bad keyboard doesn't work?

Recently you helped me fix an Air with similar issues but that mode the keyboard and trackpad connect via the same cable, on this MBP they connect via different cables.
 

2informaticos

Administrator
Staff member
KB has separate cable, but after decoding its information goes to TP.
PCH gets all TP/KB information from TP board, via TP flex...
 

No-Clean

Member
MBP came in with the problem, I did some measurements, put the board back in and it works again, this has now happened a few times in the course of 3 months.
 

2informaticos

Administrator
Staff member
Is not easy, as you have a random issue.
You can test continuity for I2C_IOXP_SCL/SDA lines between motherboard and trackpad board.
For that, you must identify corresponding pins, because TP flex is not 1 to 1.
Even then you can get good continuity and still having problems.
I recommend to test 2-3 TP cables and inspect J4802 connector.
 

No-Clean

Member
I just ordered a new trackpad cable (pulled from working MacBook) will wait for that to come and test, thanks a lot for your guidance.
 
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