# Blown Inductors on a Dell Laptop Board

#### Portastormo

Joined Feb 12, 2021
2

I have cracked open a Dell XPS13 9350 that I've diagnosed the motherboard being dead. It's my mothers old laptop. I figured this would be a good chance to learn more about the micro parts on a board. Upon taking it apart, I found some blown inductors (atleast I think theyre inductors) they're little silvery looking boxes with the Numbers "R15 623 279". Doing a bunch of research online I haven't found much.

I can't seem to find any replacement inductors or even how to read the parts. Dell isn't very generous with information about these parts.

So my question is, does anyone know what part this is and where I can find a replacement?

I have also read that if inductors were blown, other parts could be damaged. Is this true?

I attached some photos of the parts that appear burnt out.

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#### AlbertHall

Joined Jun 4, 2014
11,305
The inductors didn't burn themselves. Some other failure caused too much current in the inductor. A replacement inductor will fail the same way unless you fix the fault causing the increased current.

#### drc_567

Joined Dec 29, 2008
1,107
The section between the two R15 parts looks a little oxidized, as if overheated.
Was an additional R15 part in that location, or was it left blank?
A shorted out voltage regulator or DC to DC converter chip might be something to look for.
A sharper picture of the inductor section would allow legibility of adjacent parts.

... As suggested previously, one option is to search for an identical used motherboard or laptop and compare the parts, switching out any that look questionable.

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#### PowellRog

Joined Feb 11, 2021
6
Check all connections with a multimeter

#### Portastormo

Joined Feb 12, 2021
2
The section between the two R15 parts looks a little oxidized, as if overheated.
Was an additional R15 part in that location, or was it left blank?
A shorted out voltage regulator or DC to DC converter chip might be something to look for.
A sharper picture of the inductor section would allow legibility of adjacent parts.

... As suggested previously, one option is to search for an identical used motherboard or laptop and compare the parts, switching out any that look questionable.
There was none there, that spot is blank, and on the other side of the board there are some capacitors (it looks like). Unfortunately these replacement boards are anywhere from 300-700$and ultimately I'm trying to save as much$ as possible. If its unrecoverable without a replacement, probably not worth the investment since this thing is quite old.
Check all connections with a multimeter
Does this work if I can't boot the computer at all? Does just plugging in the charger put current through the board? I did multimeter the charging port and it is getting 20v, however testing a few chips I wasn't seeing much, unfortunately I don't have the schematics for the board and I am quite new at this so its hard for me to infer the direction.

The inductors didn't burn themselves. Some other failure caused too much current in the inductor. A replacement inductor will fail the same way unless you fix the fault causing the increased current.
I think I know why this happened and it was something she was doing that she no longer would do. (Assuming she could've done anything to increase the current.) She use to use spare monitors with adapters and hook it up to the laptop.

I put in a couple closer photos, unfortunately this is the closest I can get without it losing all focus. The backside included.

#### Rakaia

Joined Feb 20, 2021
1
Hello, I have the same problem with my laptop (turns on and switches off right away with Ram installed) with Ram removed it Boots up ,but still no display, the R15 Inductor Power Coil is getting really hot, the voltage is jumping between 1.4v to 1.8 at the R15 Pin, nothing else is getting hot, mosfets and caps have been tested and seem to be ok, the 19v, 5v, 3.3v rails are all present, no shorts to ground anywhere, 3.3v at the bios pin and start switch, I think it is the R15 Inductor Choke that is causing the problem. but i wonder what is pulling the amps to cause the heat on the chip, Cheers

#### kennybobby

Joined Mar 22, 2019
75
What makes you think the inductors are blown--how did you determine this?

What i have found in several dell laptops is that a short will appear across the 3.3V or VHCORE low voltage power supply, in some cases shorted mosfets, in others the mcu is fried, or the internal traces of the board have shorted. None were possible to repair.