Macbook Air M1 2020 A2337 - running on reserve battery (without battery)

[BMCappelletti]

Well, it took me some time to try again, cause I got a new job and didn´t have much time for it.
I replaced U5200 and on the very first try got 20V on the meter. Set it aside as it was dinner time.
Came bak, connected the meter and power again... back to 5V. Q5230 is glowing hot. I lifted L5230 and the short comes from CHGR_PHASE1. So still issues with the ISL chip? Why did it show 20V and the next try went to 5V again?

[BMCappelletti]

Sorry for interrupting, but have you tried it with a new battery? It looks like the original problem was a deeply discharged battery or a blown fuse, and if you don't have a battery repair tool, the only option is to replace it!

I don't think this board requires a connected battery to negotiate 20V. At least I don't remember connecting one to it when I first solve the original issue. And I have repaired two or three M1s before and also think I never had to connect it.

[PITERPENY]

Welll, made some progress.
Replaced U5340 with one from a donor board. Now the short on PPCHGR_VDDA is gone.
Still 5V on the meter, though.
But also 5V on U5340 pin 5 and 1V on the F5200.
Back to previous step. 5V and no current drawn, at all. Will replace the ISL again. Have one extra.

Sorry for interrupting, but have you tried it with a new battery? It looks like the original problem was a deeply discharged battery or a blown fuse, and if you don't have a battery repair tool, the only option is to replace it!

[BMCappelletti]

Welll, made some progress.
Replaced U5340 with one from a donor board. Now the short on PPCHGR_VDDA is gone.
Still 5V on the meter, though.
But also 5V on U5340 pin 5 and 1V on the F5200.
Back to previous step. 5V and no current drawn, at all. Will replace the ISL again. Have one extra.

[BMCappelletti]

Ok. So the hunt is for any leg of this shorted trace that may end up also to ground. It appears that the short is under the ISL chip but do study it when fully alert. I am into my Netflix time of the evening...

You will have to reflow with flux and gently nudge this ISL chip with hope to correct any underside balls to make them stand 'like soldiers' as Louis would say in his videos.

Did that. No luck.
So, removed the ISL chip. Still a 3.4 ohm short on C5275 PPCHGR_VDDA.
PPCHGR_VDDA goes to (among other places) R5275. That resistor is measuring fine, at 4.7 ohms. The cap above, which is C5277, is also fine.
So maybe my option is to check U5340. I do have 1.3V on the enable pin, but nothing on pin 4, which is PPCHGR_VDDA. Does this make sense?

[mon2]

Ok. So the hunt is for any leg of this shorted trace that may end up also to ground. It appears that the short is under the ISL chip but do study it when fully alert. I am into my Netflix time of the evening...

You will have to reflow with flux and gently nudge this ISL chip with hope to correct any underside balls to make them stand 'like soldiers' as Louis would say in his videos.

[BMCappelletti]

Suggest to flux and lift up one leg of L5230. Then measure on which side of this lifted inductor is shorted.

Short comes from pin2 (CHGR_PHASE2) connected to mosfet Q5240.
I removed Q5240 and short is still there.

Seems like this line comes from C5240, connected to C5275 and the ISL chip I replaced.

[mon2]

Suggest to flux and lift up one leg of L5230. Then measure on which side of this lifted inductor is shorted.

[BMCappelletti]

What is the resistance to ground of L5230?

A full short. 0.1 ohms.

[mon2]

What is the resistance to ground of L5230?

[BMCappelletti]

Well... it took a long time for the new ISL chip to get here, due to a post office strike.
Anyway, I installed it and... no luck. Still not negotiating 20V. But I noticed L5230, on the side of the board, is shorted. A full short.
Those are CHGR_PHASE1 and 2, and it comes from the mosfets beside it.
I guess it can come from a not well installed ISL chip, even though I think it is correct installed.

[BMCappelletti]

These look ok to me. At this time, suspect that the ISL9240 is defective and should be replaced. This is a very dense and small component. Proceed only if you have confidence in the process. Many videos on this topic. Watch the air pressure so you do not lose any of the surrounding components. Use plenty of flux to help.

Yep. Will try to do it without the need for reballing. Let's see how it goes. If a reballing is needed I still have some 0.35 (I think) ones that I used on a PS4 south bridge. Also have some paste.
At least it does not seem to have the undefill, that the Macbook Pro 2018 has on the CD3215 chips. I posted about it some time ago and I believe I need to replace that.
There is a first time for everything.
Thank you!

[mon2]

These look ok to me. At this time, suspect that the ISL9240 is defective and should be replaced. This is a very dense and small component. Proceed only if you have confidence in the process. Many videos on this topic. Watch the air pressure so you do not lose any of the surrounding components. Use plenty of flux to help.

[BMCappelletti]

What is the voltage on pin #1 of R5215?

The voltage on R5216 pin 1 must be the same as the voltage on R5215 pin 2. Unless there is a trace break between these 2 parts or the resistors are not soldered properly.

Nevermind. They are inverted. It is 1.2V on both.
R5215 pin 1 is 5.1V.

[mon2]

What is the voltage on pin #1 of R5215?

The voltage on R5216 pin 1 must be the same as the voltage on R5215 pin 2. Unless there is a trace break between these 2 parts or the resistors are not soldered properly.

[BMCappelletti]

This should be 5v on each side.

What is the voltage of CHGR_AUX_DET?

1.2V on R5215 pin 2. But 0V on R5216 pin 2.
Resistance on those is around 200 k ohms.

[mon2]

This should be 5v on each side.

What is the voltage of CHGR_AUX_DET?

[BMCappelletti]

Resistance is ok. Confirm the voltage on each side of this part.

0V on this resistor.

[mon2]

Resistance is ok. Confirm the voltage on each side of this part.

[BMCappelletti]

What are the voltage measurements for R5275?

4.8 ohms, across.