A2338 820-02020 TrackPad Stops Working

[RepairxD]

Issue: TrackPad & Keyboard Stops Working
Have Tried Replacing TP + Cable, Same Issues - Works for a few minutes, a few moments later, stops working fully. Occasionally has Haptic Feedback, Other times there is no feedback either. I'm not sure if this is linked with any Sleep/Wake functions. Have replaced UT301 multiple times, replaced a few potentially faulty caps.

UT301
1 - 0.364
3 - 0.541
4 - 0.313

PP1v85_S2_IPD 1.85v now switches off within a few seconds.

UT360 - Replaced (Primary Issue when TrackPad wasn't working at all)
UT101 - Replaced
CT302 - Replaced
CT303 - Replaced
CT361 - Replaced

LT400 - Previously was replaced by another Shop with a random Capacitor :/

Any advice will be appreciated.

 

[2informaticos]

First of all, welcome to the forum!

"PP1v85_S2_IPD 1.85v now switches off within a few seconds."
IPD_PWR_EN_GATE drops also?
Check UT311 input voltages too.

What about IPD_LID_OPEN_1V8?

 

[RepairxD]

Thank you, glad to be here but this has been a headscratcher. Thought I'd ask some of the best.

Board on Bench
IPD_LID_OPEN_1V8 - 1.8V Staying on currently
IPD_PWR_EN_GATE - 1.8V Staying on currently
PP1v85_S2_IPD - Turns On & Switches Off after about 3-5 seconds

UT311
1 - 1.8V 0.354
2 - 1.8V 0.353
4 - 1.8V 0.608
6 - 1.8V 0.402

 

[2informaticos]

1V85_S2_IPD is controlled by IPD_PWR_EN_GATE.
If its enable doesn't drop, UT301 should still deliver output voltage.
Remove CT304 and test again.

 

[RepairxD]

i have removed CT304 , then tested same occur..1V85_S2_IPD in this line voltage come and then gone(1.85v).. now also
IPD_P1V8_PWR_EN_RC voltage come and gone(1.8V).

 

[2informaticos]

IPD_PWR_EN_GATE drops too?

 

[RepairxD]

IPD_PWR_EN_GATE drops too?

No...stay high. 1.8volt

 

[2informaticos]

Force the signal with 10-100K in place of RT301.

 

[RepairxD]

with 50k, voltage 1.85 ok on PP1V85_S2_IPD.
keyboard and trackpad work 10 to 15 minute then not work..

 

[2informaticos]

Voltage drops too?

 

[RepairxD]

no.. voltage 1.85 ok.

 

[2informaticos]

Other JT400's voltages and signals OK?

 

[RepairxD]

I2C_SMC_IPD_1V8_SCL 1.789 V
IPD_LID_OPEN_1V8 1.792 V
TPAD_KBD_WAKE_L 1.789 V
I2C_SMC_IPD_1V8_SDA 1.793
KBD_INT_L 1.829V
SPI_TPAD_INT_CONN_L 1.779V
I2C_KBD_SDA 1.846
I2C_KBD_SCL 1.846
SPI_TPAD_MOSI_CONN 0V
SPI_TPAD_CS_CONN_L 0V TO 1.8V FLUCTUATION
SPI_TPAD_MISO_CONN VOLTAGE VARY
SPI_TPAD_EN_CONN 0V
SPI_TPAD_CLK_CONN 0V

PPBUS_AON 12 V
PP3V3_S2_TPAD_ISNS 3.3 V
PP5V_S2_TPAD_CONN 5V
PP1V85_S2_TPAD_ISNS 1.85 V

 

[2informaticos]

Try known good trackpad board/flex.