820-01700 5v short on PP1V5_UPC_TB_LDO_CORE

[No-Clean]

Board had a little bit of corrosion around UB400 and CB404/PP1V5_UPC_TB_LDO_CORE was shorted.

After removing short and replacing CB404 as well as UB400 and reballing UB300 the problem is the same.

What's weird is that PP3V3_UPC_TB_LDO starts with a higher voltage when the charger is first connected 5V~ then it starts to drop slowly.

The only port that reboots is UB400 all others stay at 5V without rebooting.

 

[2informaticos]

5V is not good for 3V3 LDO at any moment; this point to bad UB400.
Try interchanging UB300/400.

 

[No-Clean]

When I swap them UB400 now has 0V on PP3V3_UPC_TB_LDO and weirdly UB400 is still the only only one that reboots even after swapping CD3217s

 

[2informaticos]

Something more is affected by corrosion in that area.
Check all resistors and caps.

 

[No-Clean]

CB408 was slightly corroded fixed that and also replaced the other CD3217 on that same side, now both of them restart, PP3V3_UPC_TB_LDO is now 3.3V steady, the other 2 ports on the other side don't restart, should I replace those 2 as well?

 

[2informaticos]

I expect to have the problem located on the corroded area.
Change the other CD3217 chips, just in case.

 

[No-Clean]

Ok I am back with this board again, now I have replaced all 4 CD3217 and now all of them get 5V and about 0.270a on all 4 ports on both sides so that will be on all 8 port options, the battery had some charge left on it so the Mac now turns on and battery is recognized.

With battery connected I get 20v most of the time but 0.018a and Mac wont charge, also tested with new battery and same thing, sometimes with battery connected I still only get 5v on charger meter.

All test done with 96w charger.

PP3V3_G3H_RTC_X 3.3V
PP3V3_UPC_XB_LDO 3.3V
PP1V5_UPC_XB_LDO 1.5V
PP1V8_SLPS2R 1.8V

PPBUS 12.3V

 

[2informaticos]

You still have problems on USB-C areas.
Battery can't be charged until get the correct PPBUS_G3H with charger alone.

 

[No-Clean]

That part is now clear to me, I have checked all caps and resistors around the affected area against another same board, and all CD3217 are new, also checked the entire board and found nothing else, but still only 5 volts, any pointers you can give for me to check?

 

[2informaticos]

New is not equal with "good", when you buy chips form China.

Just in case, try DFU...

 

[No-Clean]

The CD3217 came from a board that had 20v on all ports but had an internal short between board layers so I know there are good, revive DFU was done and succeed but problem is still there, should I try restore after backing data?

 

[2informaticos]

Probably not the solution, but try it.
Backup data anyway!