Macbook Pro A1708 PPBUS Short

[Instafixx]

PPBUS is short. Diode Mode is 0.007
Fuse is already removed.
L7410/20/30 is also 0.007.

Someone already injected voltages before.

Can it be salvaged?

 

[2informaticos]

Remove U7410/20/30, one by one.
Check when short disappears from PPBUS_G3H; replace corresponding chip.

 

[Instafixx]

Removed U7410 .PPBUS is no longer shorted.
But the Coils L7410/20/30 are still the same reading.

 

[2informaticos]

007 is the expected reading on these coils.
Replace U7410 and give it a try.
CPU may be already damaged by overvoltage; nothing to lose.

 

[Instafixx]

U7410 replaced.
PPBUS is no longer shorted but not getting any voltage on the Fuse Pads without the Fuse and amp meter wont turn on.
Previously was getting 7V and amp meter wont turn on.

 

[2informaticos]

Fuse may be burnt, did you replace it?
What is C7050 voltage, without fuse in place?

 

[Instafixx]

I am checking without the Fuse. The machine came in with fuse missing.
No voltage and amp meter wont turn on

 

[2informaticos]

USB-C charger was recognized before you've touched U7410?
In such case, the heat applied on the board affected something else.

 

[Instafixx]

No it wasnt recognised before as well.
But was getting around 7v with the fuse removed.

 

[2informaticos]

Check diode mode readings around CD3215 chips; compare with good board.
Don't forget CC1/2 lines...

 

[Instafixx]

USBC_XA_CC1_CONN IS 2.78
USBC_XB_CC1_CONN IS 2.78
USBC_XA_XX1_CONN IS 2.78

These diode mode readings are very high. These should be 0.700 as per openboarddata.

 

[2informaticos]

Check the 4 Ace RPD Strapping resistors (page 28).

 

[Instafixx]

All 4 resistors Ohms value across pins are same as a good working board.

Found PP3V3_UPC_XA_LDO to be OL.

 

[2informaticos]

Bad solders unde U3100, or broken trace...

 

[Instafixx]

Both U3100 and U3200 has bad solders. Re-did that.
All readings are back to normal.
AMP Meter turns on as well.
But the port corresponding to U3200 - the amp meter reboots every 5 seconds.

 

[2informaticos]

The other port switches to 20V?

 

[Instafixx]

No. 5V with 0.033 current draw

 

[2informaticos]

Actually same readings (diode mode) on LDOs and CC1/2 lines on both ports?

 

[Instafixx]

Yes. All Same.

 

[2informaticos]

Remove F7000 and see if still restarts.
Also check C7050 voltage.