MacBook A2681 (Board 820-02862) - UP700 Likely Shorted

[Dylan Jones]

Hi all,
I'm a beginner at laptop repair. I bought a MacBook Air A2681 that doesn’t turn on, just for practice. PPBUS_AON and the other always-on voltages are present and look fine. I did some diode mode measurements and got unusual readings (compared to reference values I found online) on LC320 (44mV) and L82D0 (40mV). LC320 corresponds to the PP5V_S2 power rail, and L82D0 to PP1V25_S2.

I injected 1V (current limited to 100mA, the board consumed around 86mA) into PP1V25_S2 to see if anything would heat up, but everything seemed normal. I did the same with 5V (current limited to 300mA, the board consumed 300mA) on PP5V_S2, and noticed that UP700 (SLG5AP1451V) appears to be shorted. According to the schematic, this chip is part of the display power sequencer circuit, and I haven’t found any information suggesting this chip commonly fails.

Is it normal for UP700 to get warm, or is it likely shorted? I’m considering removing it to see what happens, but I’m concerned I might damage it during removal, and I'm not entirely sure that's the cause. Does anyone have experience with something similar? Any thoughts or suggestions on how to proceed would be greatly appreciated!

[Ponto da Manutenção]

It is recommended to remove it.
After removing it, you can do a test (reverse conduction on the pads).
Then we will be sure that the problem is only in the
(UP700 SLG5AP1451V).

[Dylan Jones]

Thanks! I'll remove it then. If the UP700 turns out to be the issue, would you recommend buying a replacement individually (USD $10 on AliExpress or eBay), or getting a scrap board and pulling it from there ($150 on eBay)? What do you think?

[Ponto da Manutenção]

If you have access to a "scrap" it is recommended.
Chinese products are not 100% reliable.

[Dylan Jones]

I'm going to try to get a donor board . Thank you so much for your help!