820-3435 keyboard trackpad only work in OS AND FAN RUNS IN FULL

MOMOH

New member
Hello guys , please I need your help, have got a MacBook Air 11inch whose keyboard/trackpad will only work in OS and the keyboard fan runs in full speed.

HISTORY : initially the machine would intermittently switch off , so I had to replace the SMC and it works except the issue above, so I thought maybe the SMC was not good so installed another one , but still the same.
 

2informaticos

Administrator
Staff member
Inspect USB_TPAD_P/N lines for corrosion.
Post U4810 voltages before login to OSX; remove internal SSD to avoid system booting.
If also fan runs always high, makes me thinking both problems could be generated by trackpad board/flex.
Start trying known good ones.
You can run corresponding ASD EFI version and see what error pops up.
 

MOMOH

New member
On U4810
PIN 1 = 3.3V
PIN 2 = 0V
PIN 3 = 0V
PIN 4 = 0V
PIN 5 = 3.3V
PIN 6 = 0V
PIN 7 = 0V
PIN 8 = 3.3V

TPAD_SPI_IF_EN_CONN circles between 0v,1v,2v when the keyboard is not connected , but straight 0V after connecting the keyboard
 

2informaticos

Administrator
Staff member
Missing TPAD_USB_IF_EN signal at U4810; check diode mode to ground.

I hope you measured with trackpad connected.
 

2informaticos

Administrator
Staff member
Check R1619.
If good, then is PCH issue.

Please, do NOT quote an entire post visible few centimeters above.
Maintain forum aesthetic...
 
Top