A1466 (820-3437-B) Keyboard\Trackpad not working.

[rupal]

I have an A1466 (820-3437-B)
I had to reball the SMC due to other issues. After reballing i tested the machine & all was good. So i took the board out & Ultrasonic cleaned it to clean flux residue etc..
After reassembling, when i turn it on the Caps Lock light is always on & cannot be turned off
And when booted into OS the keyboard & trackpad are not detected. (USB Mouse\Keyboard works)

With machine off i can reset the SMC via keyboard & power on/off with keyboard.
I cannot do a PRAM Reset. Tried a brand new trackpad cable with same issue.
No corrosion on J4800 area & no liquid damage.
Also, i thought i might have bodged the SMC Reball so i re-reballed it being very meticulous & exact same issue.

Any advice appreciated ?
Thanks.

 

[2informaticos]

Try known good trackpad board first.
New chinese flex can be crappy, so try other flex too.

If TP/KB worked before cleaning the board, then check for broken traces, or knocked off components on the MLB.
Post U4810 voltages.

 

[rupal]

Unfortunately i don't have a spare trackpad for it atm. But just thought i should add: on J4800 (Pin 15) "TPAD_USB_IF_EN_CONN" i am getting 1.2ohm to GND (on the trackpad with cable disconnected)
Is that a short to GND or should "TPAD_USB_IF_EN_CONN" have such a low resistance on the trackpad end ?
And "TPAD_USB_IF_EN_CONN" is only getting 0.3v when connected & 3.3v when disconnected.

Update: If i disconnect the Keyboard from the Trackpad i get 500ohm to gnd on TPAD_USB_IF_EN_CONN & when magsafe connected i get 1.5v then drops to 0.3v after power cycling...

 

[rupal]

Here are U4810 Voltages:

Pin 1 (PM_SLP_S4_L): 3.33v once power cycled
Pin 2 (TPAD_USB_IF_EN): 2.9-3.3v Fluctuating
Pin 3 (TPAD_SPI_IF_EN_CONN): 3.3v when power connected & 0v once power cycled
Pin 4 (GND): 0v
Pin 5 (PM_SLP_S4_L): 3.3v
Pin 6 (TPAD_SPI_IF_EN): 0.04v
Pin 7 (TPAD_USB_IF_EN_CONN): 3.3v
Pin 8 (PP3V3_S4): 3.3v

Also, i tried to connect a different keyboard to trackpad & same issues...
I also replaced U4810 & got same results...

 

[2informaticos]

""TPAD_USB_IF_EN_CONN" i am getting 1.2ohm to GND (on the trackpad with cable disconnected)"
Do you mean short on the MLB, or TP board?
You've just said to get 3.3V there; pin 7 of U4810.

You must get complementary logic level on pins 3 & 7; not 3.3V on both, at same time.

 

[rupal]

Short is on Trackpad side,
The voltages i listed for U4810 is with trackpad disconnected

EDIT: In other words the trackpad has a 1.2ohms to GND on Pin 15 disconnected from MLB
And the voltages for U4810 i listed are measure on the MLB (without trackpad connected)

 

[rupal]

You must get complementary logic level on pins 3 & 7; not 3.3V on both, at same time.

I will double check those voltages soon & post back. Im beginning to really confuse my self... lol

Update: Ok so i double checked & to clarify. Pin 3 gets gets 3.3v until after the MLB has power cycled & then goes 0v.
And Pin 7 gets 3.3v once MLB has power cycled.

I will order a new trackpad & go from there...
Thank You!

 

[2informaticos]

U4810 voltages are irrelevent if TP flex is disconnected.
Change TP, if you already detected short on its circuitry.

 

[rupal]

Thanks 2informaticos, I have gone & ordered a new TP...
I found it odd that it was all working until after i ultrasonic cleaned the MLB & did not even remove the Trackpad from case.
Something must have fried it i guess... Just wanted to rule out anything else.

I will post results here once i receive it.

Cheers

 

[rupal]

The trackpad was the issue, i replaced it & all works fine now.
I guess it must have just been a coincidence for the TP to die right after i reballed SMC & then ultrasonic cleaned the logic board.