A1708 820-00840-01 Chime Loop

[Aitorflores7]

Hi everyone!
I have A1708 13'' Macbook Pro with 820-00840-01 board. When i connect the charger with the amp meter it goes to 20V 600-660mA and the down to 280mA and stays there. Chime sound stays repeating all the time. No backlight, yes trackpad clicking. I don´t have an usb-c usb pendrive or mouse to test cpu activity.

PPBUS_G3H: 13.04V
PPDCIN_G3H: 20,24V
PP3V3_G3H: 3,14V

Any suggestions?

[Spider1211]

Re: A1708 820-00840-01 Chime Loop

Try to reset your PRAM and NVRAM and see if that helps.

[Aitorflores7]

Re: A1708 820-00840-01 Chime Loop

Nothing, stays like at the beginning. Starts the chime loop and to ended i have to maintain the power button. I have the touchpad click but not any light in the caps lock. Maybe bios?

[Aitorflores7]

Re: A1708 820-00840-01 Chime Loop

I found two capacitors with some cracks in PPBUS_G3H_CPU rail. In resistance mode it measure 5Kohm and rising. I attach a photo. Could it be related?

[mon2]

Re: A1708 820-00840-01 Chime Loop

The resistance are ok but crack is never good for anyone

Remove the caps off the logic board and test again.

PP3V3_G3H: 3,14V

This rail looks to be low. Can you confirm it again ?

Then remove all power -> meter in resistance mode -> check & post the resistance to ground for this rail.

[Aitorflores7]

Re: A1708 820-00840-01 Chime Loop

Sorry mon2, I made a mistake when i wrote it. PP3V3_G3H is 3,41V. Is 4,5KOhm to ground. I´m going to remove the caps now.

[Aitorflores7]

Re: A1708 820-00840-01 Chime Loop

I remove the caps and tried it again. It´s doing the same.