Macbook Air a1466 no keyboard and no touchpad

[koby058]

Hi Gentleman's

usb keyboard and mouse works

board: 820-00165-A

schematic for this board can be found here

Done power reset with external keyboard works, with internal not working.

i saw no sign of liquid on MB

tried a pad and cable from another same laptop did not worked, also tried to run it only with touchpad with the keyboard disconnected and still not working

Can you please help me start debugging ?

[mon2]

Re: Macbook Air a1466 no keyboard and no touchpad

Hi. In order of importance:

1) finally have Orri Jaffa oranges at our local store Mrs. Mon2 cannot stop eating them.

2) When you connect the trackpad & keyboard, can you power the logic board on/off with the keyboard ?

[koby058]

Re: Macbook Air a1466 no keyboard and no touchpad

Hi mon2

1. LOL, i am happy for you that your Mrs. is happy

2. yes, the laptop powers on and boot to OS, the arrow remains in the top left and no keyboard button is responding.

[mon2]

Re: Macbook Air a1466 no keyboard and no touchpad

Remove all power. Meter in DIODE mode.

Connect your keyboard / trackpad.

Red meter probe, yes red, to ground.

Black meter probe to point to test.

Measure the diode mode reading of each pin on the trackpad connector J4800.

Post each measurement with the pin # being tested.

[koby058]

Re: Macbook Air a1466 no keyboard and no touchpad

OK here it is

pin #1 0.503
pin #2 0.554
pin #3 0
pin #4 0.459
pin #5 0.461
pin #6 0
pin #7 0.569
pin #8 0
pin #9 0.568
pin #10 0.376
pin #11 0.714
pin #12 0.670
pin #13 0.496
pin #14 0.466
pin #15 0.686
pin #16 0.652
pin #17 0.655
pin #18 0.496
pin #19 0.326
pin #20 0.682

I guess pin 8 will bother you

[mon2]

Re: Macbook Air a1466 no keyboard and no touchpad

I think pin #8 is ok due to R4844 being mated with ground.

Now apply power and check the voltage to ground of each pin. Measure with caution as the power is active.

The diode mode readings look ok to me and do not show a short.

[koby058]

Re: Macbook Air a1466 no keyboard and no touchpad

Ok here it is

pin #1 0V
pin #2 0V
pin #3 0V
pin #4 0.001V
pin #5 0V
pin #6 0V
pin #7 0V
pin #8 0V
pin #9 0.002V
pin #10 0V
pin #11 0V
pin #12 0V
pin #13 0V
pin #14 5V
pin #15 0.6V
pin #16 0.05V
pin #17 0.05V
pin #18 3.36V
pin #19 3.36V
pin #20 3.36V

[mon2]

Re: Macbook Air a1466 no keyboard and no touchpad

Pins #16 and #17 are not the correct voltage. Remove the interconnect cable and review the voltage to ground of these 2 pins again.

These pins must return to a logic '1' due to local pull up resistors required on all smbus interfaces.

Confirm it. If still missing, locate the pull-up resistors for this pair and check if the pull up voltage is present or is missing.

[koby058]

Re: Macbook Air a1466 no keyboard and no touchpad

Hi, i can see now that i have 3.3v on pin 16 and 17

should i repeat all 20 pins measurements ?

[mon2]

Re: Macbook Air a1466 no keyboard and no touchpad

Yes. Are these pins the correct voltage with the cables attached?

[koby058]

Re: Macbook Air a1466 no keyboard and no touchpad

both, cable connected and not connected

so i will reply here when i re measure

[reformatt]

Re: Macbook Air a1466 no keyboard and no touchpad

Make sure you have PP3V3_S4_IPD present on pin 10. Absent in your readings. Have seen this open circuit to J4800 on one occasion and needed to run a jumper.

BTW, trackpad on these have two interface modes and depends on what you are booted to. TPAD_SPI is only used when you boot to MAC OS, USB_TPAD is used during recovery or other OS like Linux.

TPAD_USB_IF_EN_CONN is high for recovery, Windows/Linux etc
TPAD_SPI_IF_EN_CONN is high for MAC OS

[koby058]

Re: Macbook Air a1466 no keyboard and no touchpad

Hi

Here are the new measurements when the os is in the login screen

pin #1 3.42V
pin #2 0V
pin #3 0V
pin #4 0v
pin #5 0v
pin #6 0V
pin #7 0V
pin #8 0V
pin #9 0v
pin #10 2.05V
pin #11 2.66V
pin #12 2.05V
pin #13 2.35V
pin #14 5V
pin #15 0V
pin #16 3.3V
pin #17 3.3V
pin #18 3.40V
pin #19 3.42V
pin #20 3.42V

should the output of Q4800 (to pin 13) be 3.3 ?
@reformat, can you please elaborate on what you written ? about the TPAD_SPI or explain what should i measure ?

[mon2]

Re: Macbook Air a1466 no keyboard and no touchpad

Measure the voltage to ground on each side of R4830.

[koby058]

Re: Macbook Air a1466 no keyboard and no touchpad

it is 2.47 on both sides

[mon2]

Re: Macbook Air a1466 no keyboard and no touchpad

That is a low voltage and it should be 3v3.

Measure the voltage to ground @ U8000, input pins A2 / B2.

What is the voltage?

See attached. If the voltage is 3v3 then proceed to remove all power.

Meter in resistance mode.

Measure the resistance to ground of PP3v3_S4 rail.

What is the resistance?

Suspecting that the loadswitch @ U8000 is defective but will wait on your checks.

[koby058]

Re: Macbook Air a1466 no keyboard and no touchpad

I can see that U8000 is having a bit of corrosion on it, and i cannot measure it

but i can see 3.3v on pin#1 of c8000.

forgot about the resistance, i will do it tomorrow since it is late at night now

Will reply with results in the tomorrow

Thanks a lot Mon2

[koby058]

Re: Macbook Air a1466 no keyboard and no touchpad

Hi

It is 3.7K ohm

[mon2]

Re: Macbook Air a1466 no keyboard and no touchpad

The resistance is ok but suspecting this load switch is now defective and should be replaced.

Assuming the enable pin is active (pin C2), the load switch is faulty.

[koby058]

Re: Macbook Air a1466 no keyboard and no touchpad

Ok, i have replaced it then turn laptop on (magsafe no batt) the mouse working, 3.24 v on pin 10

Then i have powered it on battery and the mouse not working, so i connected the magsafe and felt the tpad is very hot , now i see this hole on the chip on tpad.
Attached.

I have avreplasement tpad but i am afraid to use it, what do you think?