Macbook Pro A1708, 820-00840, 19.9V, 60mA

[MicroSMD Lab]

I'm working on an A1708 Macbook Pro, 820-00840 board. It came in with 4.97V, 0.21A on USB-C meter. Both ports gave different readings, the other was 4.99V, 0.14A. Owner said it stopped charging but was running off battery fine. I replaced U3200 because I got 38.9ohm to gnd on C3208 which went to OL after I removed U3200. Both PP1V1_UPC_X*_LDO_BMC were 0V with original U3200. After replacing, I get 19.9V but current stuck at 60mA, I also get the missing 1.1V. I get a slightly different voltage sequence on both ports though, for the U3200 it's 5.02>12.5>19.9 and for U3100 it's 5.02>9.16>19.9. I get 13.04V at F7000 and at L7030 the voltage fluctuates between 9.7-9.8V

[mon2]

Re: Macbook Pro A1708, 820-00840, 19.9V, 60mA

1) Is the DC volts reading of PPBUS_G3H stable ? F7000, pin # 2.

2) Remove all power (no adapter / no battery).

Meter in resistance mode.

Measure and post the resistance to ground of L7030. Red meter probe on either side of L7030, black meter probe to ground.

Keep in mind that the mosfets @ Q7030 & Q7040 are switching ON / OFF to create the target voltage rail of PPBUS_G3H. For this reason, do not expect a steady DC voltage @ L7030.

However, the voltage @ F7000, pin # 1 & #2 must be stable to power the logic board.

Does this logic board power on now ?

3) Where exactly are you measuring the voltage up / down sequences of U3100 & U3200 ? Which pins ?

4) Post the voltages for:

a) PPDCIN_G3H

b) PPVBAT_G3H_CHGR_R

c) PPVBAT_G3H_CONN

[MicroSMD Lab]

Re: Macbook Pro A1708, 820-00840, 19.9V, 60mA

F7000 pin2 = Stable 13V
L7030 resistance to gnd = 4.5Mohm
Logic board does not power on
U3100 and U3200 I measure at C3*08, C3*06, C3*05, C3*04
PPDCIN_G3H = 20V
PPVBAT_G3H_CHGR_R = 20V
PPVBAT_G3H_CONN = 13V
All measurements taken with charger only, no battery connected. Does this suggest a faulty U7000?

[mon2]

Re: Macbook Pro A1708, 820-00840, 19.9V, 60mA

No, your U7000 appears to be working.

Review this webpage and post your updates:

https://repair.wiki/w/A1708_2016,_20...ar_MacBook_Pro

[MicroSMD Lab]

Re: Macbook Pro A1708, 820-00840, 19.9V, 60mA

R7192 was not there. Soldered one from a donor and all is good now. looking for a PP5V_S4 probe point led me to it. Thank you mon2 and thank you Louis Rossman!