Macbook A1990 820-01041-A No Power on

[Strolch]

I have an Apple MacBook A1990 15" 2018 board 820-01041. It just went out during operation and won't start anymore. When I connect the charging cable, there is only 5V but it shows 1.55A see picture. I exchanged the Q3200 but it didn't help .

[dellxps15]

Re: Macbook A1990 820-01041-A No Power on

remove battery and check again

[Strolch]

Re: Macbook A1990 820-01041-A No Power on

I already have, even if it is removed 5V. It also doesn't start up in the other Mac with a full battery

[mon2]

Re: Macbook A1990 820-01041-A No Power on

What is the voltage to ground of PPBUS_G3H @ F7000 ?

[Strolch]

Re: Macbook A1990 820-01041-A No Power on

Hi mon2 its 0,0002V

[mon2]

Re: Macbook A1990 820-01041-A No Power on

Remove all power. Measure the resistance across fuse F7000 and also F7001.

Are any of these fuses blown? Resistance should be ~0 ohms if ok.

Next, remove both fuses, F7000 & F7001 off the logic board.

Power up again with your adapter and measure the voltage to ground of F7000 PCB pad, pin # 1.

Pin #1 is the producer side of this voltage rail which is created by U7000 (ISL9240).

What is the voltage of PPBUS_G3H now ?

[Strolch]

Re: Macbook A1990 820-01041-A No Power on

I removed the board from the Mac

[Strolch]

Re: Macbook A1990 820-01041-A No Power on

The fuse F7000 and F7001 are ok 0 ohms

[Strolch]

Re: Macbook A1990 820-01041-A No Power on

ok i unsolder the fuses

[Strolch]

Re: Macbook A1990 820-01041-A No Power on

I had left the power supply on the board and now wanted to unsolder the fuses. I just noticed that L7030 is very hot!

[Strolch]

Re: Macbook A1990 820-01041-A No Power on

Here you can see the short circuit.

[mon2]

Re: Macbook A1990 820-01041-A No Power on

Ok - remove all power.

Meter in resistance mode.

Measure the resistance to ground @ F7000 pin # 1. Best if the fuse is removed.

[Strolch]

Re: Macbook A1990 820-01041-A No Power on

ok i remove

[Strolch]

Re: Macbook A1990 820-01041-A No Power on

but it changes by 9M ohms when measured

[Strolch]

Re: Macbook A1990 820-01041-A No Power on

Fuse is removed

[mon2]

Re: Macbook A1990 820-01041-A No Power on

Ok if the fuse is removed, the 9M ohms is on which pin of F7000 PCB pads?

Pin #1 is towards the U7000 (ISL chip). Pin # 2 is the consumer side.

Suspecting that pin #1 is with the high resistance? If yes, power up without these fuses.

Measure the VOLTAGE to ground @ Pin #1 of F7000 PCB pad.

What voltage is now present?

[Strolch]

Re: Macbook A1990 820-01041-A No Power on

pin 1 0,002V

[Strolch]

Re: Macbook A1990 820-01041-A No Power on

the 9M ohms is on Pin1 of F7000

[mon2]

Re: Macbook A1990 820-01041-A No Power on

Resistance is great but voltage is not.

Confirm the voltages on the input of U7000.

With a 5 volt adapter voltage, this regulator should kick into BOOST voltage mode to supply a higher voltage @ pin #1 of the F7000 pad.

Be sure that you are truly on pin #1 of the fuse pad.

[Strolch]

Re: Macbook A1990 820-01041-A No Power on

I hope it's right
R7015 Pin1=4V
R7021 Pin2=4V
R7022 Pin2=4V
C7081 Pin1=0V