A1398 820-00138 (brd view 820-00163) boots OK, ON/OFF OK, but no other key. Trackpad unresponsive. No click, no move. PP3V3_S4 3.3V, PP3V42_G3H 3.42V

[stef4n]

I have a A1398 820-00138-A able to boot after I press on ON. The OS loads, and I reach the login screen.
There, the trackpad does not click, the cursor does not move. It behaves as if the macbook was turned off.
Not a single key of the keyboard works.
The keyboard does have its backlight.
If I press on ALT, or ALT+CMD+P+R during the boot, nothing happens. Caps lock does not work neither (does not turn green)

On J4813, I measured
PP3V3_S4 on pin 30: 3.3V
and
PP3V42_G3H on pin 4: 3.42V

PP3V3_S3 (on C8012): 3.3V

I'm using a 820-00163 boardview; the part regarding the trackpad is different from the board that I have and can't find Q7979, XW5510, U5510 for instance

What does handle the signals coming from the trackpad and keyboard on these models ?

 

[2informaticos]

Check if J4801 gets correct voltage on its power lines.

If no keyboard reaction on boot menu (before login macOS), I suspect bad trackpad board/cable.

 

[stef4n]

Do these models work the same way as the 13" A1502, whose defective trackpad cable cause both the trackpad and the keyboard to not function ? It happens so often on A1502, but that would be a first on a A1398.

Got 13.60V on PPVIN_S4_TPAD_FUSE (trackpad cable lifted -> fans full speed)
PP3V3_S4 on pin 27/29: 3.308V
SMC_ACTUATOR_EN_R_L: 0.5V (pin 20)
TPAD_VBUS_EN: 3.3V (pin 22)
PP5V_S4_TPAD_F: 5.02V (26)


Cable replaced, 3 times just to be sure, it's not that.
Going to try with another trackpad

Edit: that was that! Bad trackpad (board). Too bad, this thing chose to die 3 days after a battery replacement

Do you know whether there are schematics for trackpad ? There is not much electronics on these boards