Focusrite Forte audio device repair - step-down DC-DC converter problem

[lasworren]

Hello,
I'm trying to repair a Focusrite Forte, a PC/MAC usb audio device.
It can work only via usb, but for phantom power it needs external power supply, 5V 1A.
At the moment is dead, no power-up at all.

I've checked the pcb and found a burnt smd autoswitching power mux ic (Tps2113Apwr, U21 on PCB, already changed).
There are also two shorted sot23-5 step-down DC-DC converter, marked as "GALRXA" (U6-U7 on PCB).
Found them here: http://chip.tomsk.ru/chip/chipdoc.nsf/vc1!readform&view=smd&cat=G&start=1501&count=500
described as NCP1521BSNT1G - NCP1521B - TSOP-5 - 1.5MHz, 600mA Step-Down DC-DC Converter. Probably adjustable version.
I suppose the damage was caused by a wrong external power supply, probably 12v instead of 5V.

Anyway, I've found exactly the same step-down converters on aliexpress, already purchased (and arrived after 5 months!). Same package, but marked as "QUW" instead of "GALxxx". I searched online for information on these ic but can't find anything for sot23-5 package.
What can I do? Do I trust the Aliexpress seller? Can I use some other buck converter, always adjustable but working on a different frequency?

thanks
f

[fzabkar]

TLV70218DBVR, Texas Instruments, 1.8V, 300mA, LDO regulator, SOT23-5, marking QUW:

http://www.ti.com/lit/gpn/tlv702

Did you try here?

https://it.farnell.com/on-semiconductor/ncp1521bsnt1g/converter-buck-adj-o-p-0-6a-smd/dp/1432258

[lasworren]

TLV70218DBVR, Texas Instruments, 1.8V, 300mA, LDO regulator, SOT23-5, marking QUW:

Thank you! At the end, I'll try to buy original NCP1521BSNT1G from another shop.

Did you try here?

https://it.farnell.com/on-semiconductor/ncp1521bsnt1g/converter-buck-adj-o-p-0-6a-smd/dp/1432258

Yes, it's also available on mouser.it, digikey.it, etc., but too expensive shipping costs (about 15-20 eur) for €2 worth of ICs.