MacbookPro A1707 Boot loop with internal KeyBoard and TP

Hi
Macbook A1707 820-00281-A have boot loop with internal KB and TP. But it boots normally without KB and TP. External KB and mouse works fine. I also checked with new Topcase with new KB and TP but still same issue.

There is no liquid damage on the board, looks very neat and clean. I have also checked the J4501 and J4500 diode mode reading couldn't find any clue. compared these diode mode reading with known good working machine which was normal.

please suggest me where to start and what i am missing.
 
Did the new MacOS install and PRAM reset as well several times.

No boot loop with Keyboard connected and TP not connected.
but there is no activity on keyboard.
 
didn't find any issue in that area.
i am getting following values

Q4530. pin 3- TPAD_SPI_CS_L_Conn- 3.28V

U4540 Pin 4- TPAD_SPI_INT_L- 3.32V

U4520 Pin 4 - TPAD_SPI_IF_Conn- 3.32V
 

2informaticos

Administrator
Staff member
Check TPAD_SPI_INT_L voltage on working board.
Remember to keep TP connected, when diagnose this problem.
 
Connected TP only. No KB.
U4540 Pin 4- TPAD_SPI_INT_L- 3.32V

U4520 Pin 4 - TPAD_SPI_IF_Conn- 3.32V

these signal stays at these value. i didn't find any change.
 
While only TPAD connected
these are the values i get
TPAD_SPI_INT_L- 3.32V
TPAD_SPI_IF_Conn- 3.32V
SMBUS_SMC_3SDA-3.32V
TPAD_SPI_CS_L_CONN-5.1v
PP5V4_TPAD_CONN-5.1V
SMC_PME_S4_WAKE_L-3.2V
SMC_ACTUATOR_DISABLE_L-3.2V
KBD_INT_L-3.3V
TPAD_SPI_MOSI-0V
TPAD_SPI_CLK_CONN-0V
KBD_I2C_SCL-0V
KBD_BLC_GSSIN-3.3V
PP3V3_S4_TPAD-3.3V
TPAD_SPI_CLK-0V
 

2informaticos

Administrator
Staff member
Your problem seems to be caused by CPU itself.
Without TP/KB machine works, as CPU is clocked to minimum.

Just in case, try clean ME BIOS...
 
can i please get the fress bios for this machine?
i tried to download from other sources that is having size problem keep saying does not match the chip size.
 
Tried installing Window 10 but no luck same response. Booting properly without TPAD. But when connects TPAD, shut downs in few seconds and reboot.
 
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