Acer Nitro 5 AN515-54 - сгорел PU301, нет питания, помогите пожалуйста

Hi, I received a non-working Acer Nitro 5 laptop (AN515-54-5133) for repair. When I plugged it into the power adapter, not a single LED lit up, no light or sound codes at all. So I unplugged it from the power source and turned it over to open it up and as soon as I did, I was hit by the smell of a burnt component.

I was hoping it would just be a capacitor, but after opening the laptop I found our suspect labeled PU301. On one side, 4 pins are bridged together on a shared copper trace, and that's exactly where the component was burnt. After desoldering it, a fused remnant of the component was left behind (completely welded on).

I'd like to ask for help identifying this component, and, if I repair the missing section of the burnt trace (I checked the remaining pins with a multimeter and they still conduct) and replace the component, whether there's a realistic chance the fault was isolated to this one part?

Unfortunately I don't have access to a schematic or boardview. I have a multimeter and a digital microscope, and some repair experience (I solder reasonably well).

Any help identifying the part or pointing me toward a schematic/boardview would be greatly appreciated. Thank you!

Any help identifying the part or pointing me toward a schematic/boardview would be greatly appreciated. Thank you!

It could be a silergy SY8288BRAC . Can you post the motherboard model number

SY8288BRAC (not CRAC or RAC)

If no short in +3V then just replace and propaply you're good.

Edit: oh участник beat me to it

It could be a silergy SY8288BRAC . Can you post the motherboard model number

Yes! I searched the archives here and it should indeed be SY8288BRAC_QFN20_3X3, the motherboard is EH5VF LA-H501P Rev: 1A (2019-09-16)

SY8288BRAC (not CRAC or RAC)

If no short in +3V then just replace and propaply you're good.

Edit: oh участник beat me to it

Thank you so much

Thanks to everyone who helped so far. Here's where I've gotten to:• Confirmed PU301 = SY8288BRAC (QFN20, 3x3mm), a synchronous buck converter that generates the +3VALWP rail (always-on 3.3V, Iocp=10A) directly from +19VB (AC adapter input). Schematic snippet confirms this.

• After removing the burnt PU301, I found a hard short to GND on the +3VALWP net (confirmed via CC mode on a lab supply — voltage collapses, current holds steady even up to 550mA, so it's a genuine low-resistance short, not just capacitor inrush).

• Traced downstream through a solder fuse into a load switch, UM2 (EM5209, dual-channel ultra-low RON load switch). After desoldering UM2 completely and testing it in isolation, the chip itself tests clean — no short on the component alone.

• However, the short is still present on the board on the net feeding UM2's input (i.e., further upstream/parallel on the same +3VALWP plane), so UM2 does not appear to be the root cause.

• Found a boardview for this model. The +3VALWP net has 73 parts/pins connected across the whole board (it's a widely distributed always-on power plane feeding multiple ICs, not a single localized branch).

Where I'm stuck:

With 73 parts on this net, manually lifting/testing each one isn't very practical, and thermal tracing hasn't pinpointed anything so far. I don't have a proper short-locator tool (like a Const Instruments OSL200), just a multimeter and lab PSU with current limiting.

Does anyone have suggestions for:• A more efficient way to narrow down the short given this many parts on one net, or

• Whether it's worth checking specific parts on this rail known to fail this way on the AN515-54 / N18C3 board (e.g. common failure points others have seen on this specific always-on rail)

Thanks again for the help so far!

Use the power map on Pg 4 of the schematic to see where this goes. Past experience is always to rule out the major components like the PCH. Schematic has RH99 and RH101 as feeding +3VALW_DSW and +3VALW_HDA. Appear to be no stuff, probably just copper links on the board so you might have to cut them in order to isolate these rails.

A dead short should show up though under voltage injection/thermal camera if it's something like the PCH. Worst case its an interlayer short in the PCB which is a bit of a nightmare.

That ic is usually used on the 3v_alw rail on acer laptops, if the short is still there after you removed the BAB one, there's 99% you have a shorted pch (which is lucky when you're repairing nitros lol) and probably some other stuff also shorted, i've found the parade usb shorted too when dealing with this on the 3v_alw rail, but not much else you can do, you need to repair that part of the motherboard, solder another power supply and replace the pch (and reprogram the bios cleaning the me region)