Dell XPS 15 9500 (LA-J191P) don't see ssd after switch replacement

[Tom_avia]

Hello,
I've got this notebook not turning on. After tear down and connecting the charger I saw heating switch IC - UZ4 on motherboard. It is G5029ARC1D TDFN2X2 in schematic. There was sign of previous attempt to solder it. So I soldered out it, but didn't find what to replace it. So I took the same switch IC from this board UZ32, because here are two SSD slots. So I thought, that the second SSD slot will work. After placing UZ32 instead of UZ4 laptop turned on and works. But BIOS shows this error 2000-0155, which means "Hard drive not installed". I tried to put SSD into other slot, but result is the same. Why SSD aren't detected if one of two switches are in place?

[mon2]

Re: Dell XPS 15 9500 (LA-J191P) don't see ssd after switch replacement

Measure the voltage on each pin of this load switch.

Was the load switch soldered in the proper pin #1 orientation?

Was the load switch properly reflowed onto the pcb?

The logic board may be sensing the absence of the load switch or ssd through a current sense feedback loop.

Is there a setting in the bios on which ssd is the active or primary unit?

[Tom_avia]

Re: Dell XPS 15 9500 (LA-J191P) don't see ssd after switch replacement

Ordered APE8937 ICs from China. After soldering it in everything works well. Thank you for attention.

[mon2]

Re: Dell XPS 15 9500 (LA-J191P) don't see ssd after switch replacement

Thanks for your positive update for the closure of this thread. That is a very clever part replacement and should work fine.

Is this the same part that was onboard your logic board ? Just curious.

Datasheet is attached for future readers.

[Tom_avia]

Re: Dell XPS 15 9500 (LA-J191P) don't see ssd after switch replacement

Yea, nothing special, just simple analog of that switch IC.