MacBook Air A1932 820-01521-02

[naderk]

Hello,

I am trying to repair the laptop mentioned in the title. I have been searching posts looking for readings similar to mine but cannot find any. I am fairly new at this so please be gentle 🏳

History:
No water damage, screen cracked. Laptop doesn't draw any amps on USB meter from either USB C port. Removed the board, same no amp draw. No standby light on the board. Apart from dust board looks great! No obvious visible burnt components. At the moment I dont have a Mac charger, its on the way. I am using a samsung USB C charger which should get the board on at least? Unless I'm mistaken?

Readings:
I have measured the following after checking the fuses F3000 and F3010, both seem fine showing 5v and continuos when connected to their corresponding USB C port.

PPBUS_G3H= 0.428v
PPBUS_HS_CPU= 0.427v
PPDCIN_G3H= 5.034v
PP5V_G3S= 0v

PP5V_G3S = resistance with no power, + to GND = 0.10 M ohm & dropping, diode mode RED PROBE to GND 0.423v

Fuse Diode Readings 0.183
Voltage
F3010 is 5.040V
F3000 is 5.040V.

U3100 LDO Diode Mode Readings

PP1v8_UPC_XA_LDOD is 0.493
PP1V1_UPC_XA_LDO_BMC is 0.529
PP3V3_UPC_XA_LDO is 0.509
PP1v8_UPC_XA_LDOA is .533

Any help is appreciated. I theres anything else I should measure? I have checked the above for shorts and none found. I dont have a thermal camera yet, just need to sell a kidney first.🤔

Thank you

[mon2]

PPBUS_G3H= 0.428v

Remove all power. Meter in resistance mode. Measure the resistance to ground of PPBUS_G3H.

[naderk]

Hi mon2,

PPBUS_G3H = 8.3 mohm and dropping

[mon2]

https://repair.wiki/w/MacBook_Air_A1...A_at_5V_repair

[naderk]

Thank you! I'll run through that and see how I go.

[naderk]

Check PPBUS_G3H Voltage = 0.428v
≈0 V = Short to ground or absent voltage due to a creation problem. Proceed to repair steps below for shorted or absent PPBUS_G3H voltage.

Just out of interest I measured PP3v3_G3H_RTC Voltage on C3100 and C3200 both 0v,
however PP3V3_UPC_XB_LDO and XA are both showing 3.3v (C3108 & C3208)

PPBUS_G3H Absent or Low with No Short
C7024 or C7026 both showing 5v

CD3215 Troubleshooting
R7021, R7022, R7061, R7062 all showing 1.2-1.5 ohms

According to the wiki, ISL9240 (U7000) chip seems to be the culprit. I'll order a couple along with some CD3215 just incase.

Thank you mon2 for your help.

[mon2]

PP3v3_G3H_RTC Low or Absent

• Diagnose possible shorted capacitor around CD3215 or from CD3215 itself.
• Check GHGR_EN_MVR signal produced by ISL9240 (U7000).
  • If PP3v3_G3H_RTC is not shorted, check for its enable signal, GHGR_EN_MVR. CHGR_EN_MVR is produced by the ISL9240 (U7000). The ISL9240 commonly fails in a way that prevents CHGR_EN_MVR from being produced. If the enable signal above is missing, replace the ISL9240 (U7000.)

[naderk]

There are no shorts around both CD3215 chips, I tested all caps around them.
Yeah this next part was a little confusing, I checked CHGR_EN_MVR (R6960). Wiki doesn't tell you what the signal should be? I researched and found it should be 5v as per PPBUS_G3H which is reading 5v, is that correct ? I'm reading 0.001v or 00.58mv at CHGR_EN_MVR (R6960). I'm assuming thats too low, so it all seems to point to ISL9240 (U7000.)

[mon2]

Are each of the power rails on the CD3215 present? The 1v1 rail will only be present for the active USB-C port.

reference:

https://logi.wiki/index.php/CD3215_Bootup_Sequence

[naderk]

It seems that the answer is no, 1v1 measuring the PP1V1_UPC_XB_LDO_BMC on either USB port is 0v.
That means both CD3215 chips are bad?

Step	Source	Name of Net	Voltage	My Voltages
1	J3300	PP20V_USBC_XB_VBUS	5V	5v
2	U3200 (Check these voltages on each CD3215)	PP3V3_UPC_XB_LDO	3.3V	3.3v on each CD3215
		PP1V8_UPC_XB_LDOA	1.8V	1.8v
		PP1V8_UPC_XB_LDOD	1.8V	1.8v
		PP1V1_UPC_XB_LDO_BMC (On active port after reading TBT ROM) BMC stands for "Binary Mark Code" which is a communication protocol for PD interface. Lack of this LDO is a clear indicator that either cd3215 is failed or its bootcode is corrupted	1.1V	0v
3	U3200	HV_GATE1	High(5v, later 20V)(Air 10v, later 20V)	10v
	U3200	HV_GATE2	High(5v, later 20V)(Air 7.8v, later 20V)	6.19v
4	Q3200	PPDCIN_G3H	5V	5v
5	U7000	TBA_VDDA (PPCHGR_VDDA)	5V	5v
6	U7000	PM_EN_P3V3_G3H (NC_CHGR_EN_VR1)	3.3V (5V on many boards)	Not too sure about this, points to U7000 chip and then maybe PPBUS_G3H = 0.427v or PPDCIN_G3H_CHGR_AMON = 5v. Couldnt find PM_EN_P3V3_G3H
7	U6903	PP3V3_G3H	3.3V	0v
8	U5000	PP1V2_G3H_SMC_VDDC or PP1V2_S5_SMC_VDDC	1.2V	couldnt find these in the schematics
9	U5165	PP3V0_G3H_AVREF_SMC or PP3V0_S5_AVREF_SMC	3.0V	couldnt find these in the schematics
9.1	U7000	SMC_RST	3.3v	couldnt find these in the schematics
10	U5000	SMBUS_SMC_4_G3H_SCL	3.3V (clock)	couldnt find these in the schematics
	U5000	SMBUS_SMC_4_G3H_SDA	3.3V (data)	couldnt find these in the schematics
11	U3200	USB_XB_CC1 (USBC_XB_CC1)	0.8V (data) (verify)	0.8v
	U3200	USB_XB_CC2 (USBC_XB_CC2)	0.8V (data) (verify)	0.8v
12	J3300	PP20V_USBC_XB_VBUS	20V	5v
	J3300	PP20V_USBC_XB_VBUS	20V	5v
13	J3300	HV_GATE1	>20V	couldnt find these in the schematics
	J3300	HV_GATE2	>20V	couldnt find these in the schematics
14	Q3200	PPDCIN_G3H	20V	5v
15	R7015	TBA_AUX_DET	5V	CHGR_AUX_DET = 0.4v - 1.1v, this one was jumping all over in the range noted above
16	U7000	SMC_RST_L	3.3 (verify)	closest was CHGR_RST_IN = 0v
17	U7000	Q7030 Q7040 opening	Unknown (low maybe)

[mon2]

USB-C is a reversible interface. There is a top half of the blade and a bottom half of the same connector blade.

Attempt the following:

a) unplug the power adapter from the mains (AC) socket. This is desirable so that the power supply is not 'hot' on the USB-C port.
b) unplug the USB-C cable and rotate it by 180 degrees. Insert into the same USB-C connector on the logic board.
c) now plug in the mains (AC) socket to power the adapter.

Now do you see the 1v1 power rail for the BMC circuit? Repeat for the other CD3215.

If still no go, remove all power. Meter in resistance mode.

Measure the resistance to ground on this PP1V1_UPC_XB_LDO_BMC rail. What is the exact resistance to ground? If the resistance is very low, this low current power rail will fail to function.

Suggest to also review the USB-C connector on the paddle boards that are onboard the logic board. Be sure they are clean of debris; suggest to wipe the contacts with a cotton swab and IPA (alcohol).

[naderk]

I repeated the procedure exactly as you advised.
PP1V1_UPC_XB_LDO_BMC = 0v (C3204)
PP1V1_UPC_XA_LDO_BMC = 0v (C3104)

Measure the resistance to ground on this
PP1V1_UPC_XB_LDO_BMC = 200.7 kohm (C3204)
PP1V1_UPC_XA_LDO_BMC = 201.5 kohm (C3104)

I inspected the USB C paddles and both connector on the logic board and USB board, cleaned all, they looked ok and the connectors no debris. (see pics, FYI residue on the board is IPA)
I re-did the entire procedure after cleaning, same readings as above.