Dell Inspirion N5110

[dspok]

Hello everyone,

Board: DQ15 Discrete Nvidia
PL9201 pad2 shorted
PL4101 pad1 shorted

SIO brunt, replaced. KBC on gate brunt, replaced. Injecting little volt to PL4101 Pad1 consumes little current nothing heats, PL9201 Pad2, Nvidia chip heats.

Please help , to find the faulty component.

[dspok]

Re: Dell Inspirion N5110

Schematics here,
https://www.badcaps.net/forum/showthread.php?t=23407

[BlueMidnight]

Re: Dell Inspirion N5110

Ignore PL9201 for now. Power rails with very low voltage and high current always look shorted (e.g. CPU and GPU power rails).

The PL4101 rail should definitely not read as shorted. In diode mode, with red probe on ground and black on PL4104, you should read approximately 0.200V-0.600V (i.e. one diode drop). How much current does it draw when you inject 3.3V?

"KBC on gate brunt"
Assume you mean burnt. Correct me if I'm wrong please.
You mean the SIO and another chip were burnt? Or you mean that part of the SIO was burnt?

Also if you mean literally burnt, make sure there is no scorching/charring on the board (including underneath the chip). That stuff is conductive.

[dspok]

Re: Dell Inspirion N5110

I mean U2701 and Q2703 was fried, sorry for bad english.
PL4101 rail reading 0.012v with both side of probe.

I found another short PIN12 of U2701 (U2701 is currently off board).

[BlueMidnight]

Re: Dell Inspirion N5110

No problem. Your English isn't very bad at all.

Alright, so you do have a short on the 3D3V_S5 rail. If you look at page 100 of the schematic it shows everything that rail connects to. The problem could be any little component in any of those circuits. But because it doesn't act shorted when you inject power ("consumes little current"), maybe the bad component is one of the switches or regulators listed on that page. Or maybe a component on the other side (downstream) of them.

Some things to try:
- Remove U3602 and then check PL4101 for a short again.
- Remove PU4702 and then check PL4101 for a short again.
- If that notebook has a LAN port, then it says there should be a switch (p/n: PA102FMG) for that circuit. But it's not listed anywhere else in the schematic. I think it's on the I/O board plugged into IOBD1. Maybe. But that board can just be unplugged (if it's not already) and then test PL4101 again.

Hopefully that narrows down where the short could be. Removing 100 capacitors, etc. on the 3D3V_S5 rail would be no fun at all.

Pin 12 of U2701 is the 1D05V_VTT rail, and that is downstream from U3602. So if the short on PL4101 goes away when U3602 is removed, then the same problem may be causing both shorted readings. (For example, PU4501 or PU4503 might be bad.. or something else around there). Just try to narrow it down by removing as few components as possible.

[dspok]

Re: Dell Inspirion N5110

Thanks @BlueMidnigt
I found more short, Fan controller is blown too..
It looks like this mobo has big headache, thinking to give up..

[BlueMidnight]

Re: Dell Inspirion N5110

Sometimes that's the best thing to do. But maybe if you fix it, future generations will tell stories and sing songs about your bravery. :P