Alienware 17 (R5)LA-9331P short

[capelord]

Hi guys ,
I have a little know how when it comes to this sort of thing , not a lot though. So here is the situation that I find my self in . Not sure how but my laptop died, when ever I plug the power in to the DC jack the blue light on the power lead turns off and you can smell a short coming from the jack. I have google around and so far all it indicates is that there is some sort of short on the board, I can not afford to buy a new board so my only option is to try and find the short and repair it. So far the things that I have found and done are :

0. I have tested with two different power leads and have checked the out put from them both, both are good.
1. I have removed the DC jack and plug that in to the power lead , blue light stays on.
2. I have used a different DC jack , blue light on power lead still turns off.
3. by passed the DC connector on the board and blue light on lead still turns off.
4. unabale to try the battery as that is flat, And I don't know of anyone that can charge it for me.
5. the only thing on the board that looked suss was cap PC102 it has lost the colour off the top and it feels like a small indent on the top. Its the only cap that looks in poor condition.
5. once the power lead blue light turns of it only gives 0.450 and that drops over time,
6. using the 0.450 from the power lead and the Schematic I was able to trace the 0.450 to PQ703 and that seems to not be getting the 0.450.
7. I have checked a few parts to see if the 0.450 is getting through and I have been able to pick it up in the following locations
PQ501
PQ502
PQ503
PQ504
PQ512
PQ507
PQ508
PQ502
PQ511
PL3
PL1
PQ704
PQ702
PC905
PC906
PQ701
PC915
PL702
PL701

So far this is all I have checked , any help that you could offer would be good , and any tips on what else I can try , I don't want to waste this laptop.
I have included photos and the Schematic for it.

[smali]

Re: Alienware 17 (R5)LA-9331P short

First you start from PL1 or PR703 check with multimeter on ohm range with Ground if showing 0 ohm then something short on main voltage line..so the simple way to trace out short component inject external supply 10 0r 12v with high ampere on PL1. The positive wire on PL1 and negative on Ground and observe the board components the short component will be heat up.

[dellxps15]

Re: Alienware 17 (R5)LA-9331P short

use pjp point to see where short is......of course using a logic with brain....

a lab psu will do the rest if u dont want to remove each component or jumper.

u have short on mail 19 volt rail that power almost everithing in the notebook. i had a similar problem o ndifferent notebook and without a lab psu took me a while to figure out wich component it was, but with a lab psu, u can find the short in lower time.

it can be a bad 0805 capacitor, or a bad mosfet, or a bad ic .

[capelord]

Re: Alienware 17 (R5)LA-9331P short

First you start from PL1 or PR703 check with multimeter on ohm range with Ground if showing 0 ohm then something short on main voltage line..so the simple way to trace out short component inject external supply 10 0r 12v with high ampere on PL1. The positive wire on PL1 and negative on Ground and observe the board components the short component will be heat up.

So I hooked up a external supply and only injected 5v I wanted to start small and right away I got smoke and it bubbled up on me (PR703).
the rest were very hot but didn't bubble.
I know I will need to replace PQ703 , will I need to replace the other that got hot?

On a side note I did have a 0850 capacitor blow out as well , I have replaced that one , not the best work I have done but it should do.

[smali]

Re: Alienware 17 (R5)LA-9331P short

if you inject supply on PL1 side and PR703 heatup its mean your short circuit is after the PR703 as tick in image apply your 5V external after PR703 and observe the board components....and also the PR703 on multimeter after bubbled up the value must show very low ohm.
Note...i dont understand your 0850 capacitor..what is board part number?

[capelord]

Re: Alienware 17 (R5)LA-9331P short

if you inject supply on PL1 side and PR703 heatup its mean your short circuit is after the PR703 as tick in image apply your 5V external after PR703 and observe the board components....and also the PR703 on multimeter after bubbled up the value must show very low ohm.
Note...i dont understand your 0850 capacitor..what is board part number?

Sorry not PR703 it was PQ703 that heated up and bubbled on me, I have marked it with a red arrow, the 3 next to it with the black arrow seem to be leaking and super hot.

as for where to inject the 5v next you say after PR703 I'm not to sure which side of it I have to do it .
If you could point out on a picture of the board I will inject there. I have marked it A or B. sorry I'm still new to all this.

not sure on the board part number ? but its the I marked in the photo saying blown

[smali]

Re: Alienware 17 (R5)LA-9331P short

As per picture point-B of PR703.
as per schematic PQ703 and PQ706 are parallel for same purpose.
you can remove PQ703 temporary just for checking ....but i dont think that your main rail line voltage short with ground is the problem of PQ703...

[PitViper]

Re: Alienware 17 (R5)LA-9331P short

New to the forums, cool to see communities like this.

After doing a search this is the closest thread I could find to my problem. Keep in mind I don't know about this kind of stuff.

My issue is with and Alienware 18 with an LA-9332P (rev 1.0) (A00) mother board. The IC labled PQ703 had a total melt down. There are a cluster of 4 ICs (PQ706 PQ703 PQ702 PQ705) that all appear to be stamped as follows.

6405
BA3X15

I'm looking to find replacement ICs, but I have no idea how to find the part.

I've only done some mild soldering but I would like to try replacing the chip(s) before spending $300 on a new motherboard.

If nothing else get the chip and give someone else do the soldering.

This wasn't a cheap laptop so I'm not ready to give up on it when it does what I need it to do.

[ivmilicevic]

Re: Alienware 17 (R5)LA-9331P short

I'm far from expert on this, but according to schematics those chips are P-Channel Mosfets - Si7149DP. They seem to be common in laptops, so they shouldn't be too hard to find.
Although it's possible that something is shorted after these mosfets, so even if you replace them with new ones problem could still be there

[PitViper]

Re: Alienware 17 (R5)LA-9331P short

I'm far from expert on this, but according to schematics those chips are P-Channel Mosfets - Si7149DP. They seem to be common in laptops, so they shouldn't be too hard to find.
Although it's possible that something is shorted after these mosfets, so even if you replace them with new ones problem could still be there

Thanks! Any info is very much appreciated.

I was thinking the same thing about there being a short elsewhere. Hoping the chip was just bad. This isnt the first time ive had a problem and both times the same program was running. For some reason I think the program was pushing the GPUs too hard. last time it killed one of the GPUs, now this happened after getting a replacement. But when I only had one GPU everything was fine.

[maki]

Re: Alienware 17 (R5)LA-9331P short

Hello
I have a weird issue with my laptop - Alienware 17 (R5).
For a while I worked only on AC (no battery installed) without any issues.
Recently I’ve bought a battery. At the beginning it looked like its working fine and after a while I’ve noticed that it isn’t charging.
I’ve removed the battery and the laptop wouldn’t turn on AC only.
So, now it works fine only on the battery and won’t turn on with AC.
Any ideas?

[mcplslg123]

Re: Alienware 17 (R5)LA-9331P short

check dc in fets

[maki]

Re: Alienware 17 (R5)LA-9331P short

Thanks for the response, mcplslg123. To which FETs are you referring?
When AC is connected (without battery) the MoBo has 5V and 3.3V.

[boss juben]

Re: Alienware 17 (R5)LA-9331P short

Hello
I have a weird issue with my laptop - Alienware 17 (R5).
For a while I worked only on AC (no battery installed) without any issues.
Recently I’ve bought a battery. At the beginning it looked like its working fine and after a while I’ve noticed that it isn’t charging.
I’ve removed the battery and the laptop wouldn’t turn on AC only.
So, now it works fine only on the battery and won’t turn on with AC.
Any ideas?

same problem did any one have solution for this problem but i will try may best to solve this