820-00840 MBP 13" 2016 - Liquid Damaged - Dead - No PP5V_S5, PM_SLP_S4_L, PP5V_S4

[Alan.L]

820-00840 MBP 13" 2016 - Liquid Damaged - Dead - No PP5V_S5, PM_SLP_S4_L, PP5V_S4

USB-C circuit was fcked. corrosion on U3100 and the same area of the back as well. I had to replace U3100,U7650, Q7680 and fix a couple of missing traces.

before rework iget no voltages anywhere at all. after U3100 area rework, I get 20v on PP20V but sometime I get 5.2v then give it a minute or so then the voltage rise to 20v.


ppbus_g3h = 13v
pp3v3_s5 = 0.4v
PP3V3_LDO3V = 3.3
3V3_S5_SMC = 3.3
pp3v3_g3h 3.4
PP3V1_RTC = 3v
PP3V3_G3H_UPC_XA 3.3v

PP5V_S5 = 0
PP5V_S4 = 0v

SMC_PM_G2_EN = 3.4V
PM_SLP_S4_L = 0V
ALL_SYS_PWRGD = 0V



Do i have a dead SMC or U7800?


i have two 820-00840 donor boards. what stencil pitch size i use on this new SMC?

 

[dukefawks]

So G2_EN is present and 3v3_s5 is not. I would say something around U7650 is a problem.

 

[Alan.L]

Is it possible the u7659 replacement i took from a donor is bad?

 

[dukefawks]

Possible or bad soldering. Replace it again including both FETs on the 3V3 side and check resistors/traces around there too, especially the VIN pin.

 

[Alan.L]

While replacing u7659 with a new one, then I notice “R7686” resistor was missing. I must have forgotten to put this resistor back on. Logic board can power up and boot now. But battery status says “replace now” and won’t charge. Is it possible I have a bad communication battery circuit, don't really want to replace the battery, it looks new.

 

[JohnB8812]

Um no replace now means replace now lol. You could install the board in a different housing if you have one and see if that goes away to confirm it's the battery.

 

[Alan.L]

nope, they are super expensive. I did replace U7000 from a new spool, could this have caused? I've heard original chip contain firmware.

 

[dukefawks]

Just a dead battery