Macbook Pro A1707 820-00281 Stuck @5V

[JasonC89]

Given that there is no short on this low current rail, you could consider using your DC power supply and limit the current of your external power source to 500mA and inject as you are considering @ R6923 (without R6923 installed). This will confirm that U6903 is defective since it wimps out upon attaching the downstream (consumer side) load.

I tried this and it kicks the charger to 20V.
Current on the charger goes up over an amp and then drops down to almost nothing. (maybe to be expected since it's not taking to the regulator.

[mon2]

Excellent. Replace U6903 and consider to also replace the dual common cathode diode and test again.

[JasonC89]

Okay, so I think I have it sorted. Upon testing R6907, instead of 2R2 ,I was getting around 62 ohms, I replaced it with a new resistor, and tested and the charger immediately went to 20V.

Im getting 3.4V on R6923 (while on the board) and Im getting 12.61V on PPBUS_G3H.

D6902 is also bad though, as when I put it back on the board instead of the wire I had for testing, it no longer was getting 20V from the charger and the other voltages also dropped to the old values.

A new diode (need to source a replacement, would windows laptops have similar ones?) and it should be back up and running!

Really appreciate your help on this mon2 you really helped with the whole troubleshooting process. Thank you

[mon2]

Bravo! Well done. The least I can do for the great music from your side (U2 / Pogues / Van Morrison)

Yes, you may be able to find one on the charger IC of any laptop. It will be used in a similar way - one anode will be from the battery / other anode from the DC power adapter. Cathode to the charger IC to power via VCC pin. However the physical fit may be a bit off but will work if you can squeeze it onto the PCB pads. Worth a try.

Otherwise...

D6902 = BAT30CWFILM

BAT30CWFILM STMicroelectronics | Discrete Semiconductor Products | DigiKey

Mouser should also have stock of these.

[JasonC89]

Bravo! Well done. The least I can do for the great music from your side (U2 / Pogues / Van Morrison)

Yes, you may be able to find one on the charger IC of any laptop. It will be used in a similar way - one anode will be from the battery / other anode from the DC power adapter. Cathode to the charger IC to power via VCC pin. However the physical fit may be a bit off but will work if you can squeeze it onto the PCB pads. Worth a try.

Otherwise...

D6902 = BAT30CWFILM

BAT30CWFILM STMicroelectronics | Discrete Semiconductor Products | DigiKey

Mouser should also have stock of these.

Good taste in music I see

Perfect, I will have a quick look at some boards I have here, if not I will order from a local electronics site, they seem to have the exact correct one (although they have a MOQ of 25 lol).

Thanks again and enjoy your day! (or night lol)