A2442 820-02098 5v 0a

[sewsulle]

Good afternoon,
I'd appreciate help diagnosing my A2442 that's only taking 5v and 0a

This was my personal laptop and I had closed it at the end of a class and opened it in the next class when it just didn't wake up from sleep (The battery was charged). I connected a charger later that night and it booted right up but touch ID stopped working. The next day it did the same thing but never turned back on when I plugged in a charger.

I though the touch ID issue was weird but I'm not sure if that info helps.

When this happened months ago I tried to diagnose the issue and suspected U5200 but there is no visible damage.

I'm not sure where to start with this one and any help would be appreciated. I only have experience working on intel boards. This is my first M1.

Thanks in advance

[mon2]

What is the voltage to ground of:

PPBUS_AON @ F5200 / F5201 ?

Check both sides of these fuses.

[sewsulle]

I have 0.97v on both sides of each fuse

[mon2]

Remove all power. Meter in resistance mode (not diode). Measure the resistance to ground of PPBUS_AON at either of these fuses. What is the measurement?

[sewsulle]

PPBUS_AON resistance to ground is 109.4 ohms

[mon2]

This is a low resistance value for PPBUS_AON.

Flux and remove both of these fuses @ F5200 and F5201. Then measure the resistance to ground again to note which side of the fuse(s) is shorting?

Is it the producer (ISL9240) side or the consumer / downstream side. After the fuses have been removed, power up again and measure the voltage to ground at the PCB pad where either of the fuses were soldered. Measure at the upstream or ISL9240 side of the PCB pad.

What is the voltage to ground now (without the downstream loading since the fuses have been removed)?

Update:

Do confirm the voltage from the power adapter is reaching the ISL9240 - check the voltage to ground of PPDCIN_AON.

[sewsulle]

I have 12.4v on the producer ISL9240 side. As I understand, that means U5200 is not the problem.

The consumer side is shorting

Edit:

PPDCIN_AON: 5.3v

[mon2]

Measure the resistance from this downstream fuse pad to test each and every inductor (usually are grey in color). If you measure a low resistance,post a list of which inductor. Checking a high side mosfet shorting.

[sewsulle]

Good Morning,

Resistance from downstream fuse pad:
L5230: 156.6 k ohms
L5840: 108.1 ohms
L5820 108.1 ohms
L5800 108.1 ohms
LF800: 1.46 k ohms
LN480: 1.34 k ohms
LP800: 6.5 k ohms

I also noticed that UR660 looks slightly damaged. I'm not sure if this could be the problem.

[mon2]

Post a pic of UR660. It may be a factor or may have been damaged from a leaky high side mosfet.

L5840: 108.1 ohms
L5820 108.1 ohms
L5800 108.1 ohms

These are of concern. Remove all power. Meter in resistance mode. Measure the resistance to ground of any of these inductors. What is the measurement in ohms?

[sewsulle]

Unfortunately I won't be home or have access to the board until Wednesday.

I really appreciate your help and will post a pic and measurements ASAP.

[sewsulle]

Thank you for your patience.

Resistance to ground on L5800, L5820, and L5840 is 2.8 ohms

I've attached a pic of UR660. There are indents/chips in the surface and a nearby capacitor, CR663 is missing.