820-01521 (MBA A1932) - pulling 5V and 0,008A

[jub]

Hi, i have a MBA which does not turn on and try to restore the data, thats the goal. There were some signs of corrosion (although the owner said, its unlikely that there was a water damage) around C6415, Q7660, Q7680.
First, it pulled 5V and 0,018 A (both ports) - i exchanged ISL9240 (U7000) with a new one, same result (on advice from here https://repair.wiki/w/MacBook_Air_A1932_Not_turning_on,_pulling_0.00-0.02A_at_5V_repair - section "PP3v3_G3H_RTC Low or Absent"). I replaced it again with a chip from a donor board, now its getting bad: 5 V and 0,008A. I am waiting for new (and cheaper) chips from aliexpress.

Better to wait for the new chip ans measure again?
Thanks!
(all measures are current voltages with a usb-c charger and NO battery)

PPBUS_G3H = 0V
PP3V3_G3H = 0V
PPDCIN_G3H = 5,12V
PP3V3_G3H_RTC = 0V
CHGR_EN_MVR_R = 0,13V
PPDCIN_G3H_CHGR_AMON = 5,12V
CHGR_AUX_DET = 1,27V
CHGR_HPWR_EN_L = 0V

usb-c connected to XB // XA:
PP1V8_UPC_XA_LDOD = 0V // 1,79V
PP1V1_UPC_XA_LDO_BMC = 0V // 0V
PP3V3_UPC_XA_LDO = 0V // 3,27V
PP1V8_UPC_XA_LDOA = 0V // 1,79V

PP1V8_UPC_XB_LDOD = 1,78V // 0V
PP1V1_UPC_XB_LDO_BMC = 0V // 0V

usb-c connected to XB:
PP3V3_UPC_XB_LDO = 3,3V
PP1V8_UPC_XB_LDOA = 1,8V
PP1V8_UPC_XB_LDOD = 1,78V

usb-c connected to XB:
UPC_XA_GATE1 = 5,3V
UPC_XA_GATE2 = 0,48V
UPC_XB_GATE1 = 10,9V
UPC_XB_GATE2 = 7,0V

 

[2informaticos]

First of all, welcome to the forum!

Post diode mode to ground readings at PPBUS_G3H & 3V3_G3H_RTC.
Also post U7000's basic voltages: P_IN, AUX_DET, SMC_RST_IN, VDDA/P, EN_MVR, AUX_OK, A/BMON.
Use adjacent components as test points.

 

[jub]

Thank you! I'm excited...

values diode mode (red to ground):
PPBUS_G3H = 0,473 V
PP3V3_G3H_RTC = 0,455 V

Voltages:
P_IN (PPDCIN_G3H_CHGR_AMON) = 5,12 V
AUX_DET (CHGR_AUX_DET) = 1,27 V
SMC_RST_IN (CHGR_RST_IN) = - 0,001 V
VDDA (PPCHGR_VDDA) = 0 V
VDDP = 0 V
EN_MVR (CHGR_EN_MVR) = 0,13 V
AUX_OK = (is that NC_CHGR_AUX_OK ? -> NC)
CHGR_BMON = 0,067 V (measured after R5470 - 4.53K, as SMC_BMON_ISENSE) (stupid idea to measure here??)
CHGR_AMON = 0,057 V (measured after R5472 - 4.53K, as SMC_DCIN_ISENSE)

 

[2informaticos]

You should done these measurments before changing the chip; be aware in the future.

Check diode mode at VDDA/P lines.
If no short, then bad U7000, or bad solders.

 

[jub]

Thank you for your quick answers and help!
I have done some (basic) measurements and with the infos from repair.wiki i decided to exchange the chip (mainly because of the missing CHGR_EN_MVR and no found shorts).

I think, i have done something wrong with the soldering (VDDA is OL). Now i am waiting of the new chips (i cannot reball the first chip, no stencils with the right diameters... ) and will do my best to solder it better.
Please be assured, that i will be back