Dell Latitude E5450 Power Short Circuit

[frank123]

Hello to everyone

I have a problem with my Dell Latitude E5450.
When I insert the dell power jack into the laptop, the led on the jack turns immediately off, I tried with a different charger that does not have the self-ciruit test like the dell original adapter, and the laptop does not turn on, and no lights on the laptop.
I disassembled the motherboard from the laptop, and I don't know if this would be helpful but, I noticed that when i plug off the charger ( the non original one) from the motherboard, the CPU fan moves a little bit, but a little little bit.
I would be really grateful if you helped me, thank you so much

P.S. I enclose here the schematics of this laptop, the motherboard revision on this pdf is 0.3, on my motherboard is 1.0

[stj]

Re: Dell Latitude E5450 Power Short Circuit

try without the cpu.

[frank123]

Re: Dell Latitude E5450 Power Short Circuit

try without the cpu.

The CPU is soldered

[stj]

Re: Dell Latitude E5450 Power Short Circuit

damn.

[heartbeat]

Re: Dell Latitude E5450 Power Short Circuit

it could be the power jack.while you got the motherboard out plug the power supply in and check to see if you have your voltage.

[ktmmotocross]

Re: Dell Latitude E5450 Power Short Circuit

"When I insert the dell power jack into the laptop, the led on the jack turns immediately off"

so it work on battery?

check all big grey coils for short to ground

[frank123]

Re: Dell Latitude E5450 Power Short Circuit

"When I insert the dell power jack into the laptop, the led on the jack turns immediately off"

so it work on battery?

check all big grey coils for short to ground

Grey coils are in good condition, the battery is low , so I am not able to test, but the laptop seems dead, I noticed with the other charger( that does not have the self-test circuit), the motherboard starts to heat up in around the area where the electric current enters

[ktmmotocross]

Re: Dell Latitude E5450 Power Short Circuit

"Grey coils are in good condition"

i dont ask about it's condition

[SoporteHR]

Re: Dell Latitude E5450 Power Short Circuit

Hi.

Check that the first Mosfet's and Diodes near the power supply jack are not short-circuited.

[saveE5450]

Re: Dell Latitude E5450 Power Short Circuit

I got a short circuit situation as well, with the charger plugged in, LED on, plug it into the laptop DC jack, LED goes out. All the posts I've seen point to the bad motherboard. If anybody has any idea on how to troubleshoot and replace the diodes/MOSFETs, I'd like to fix it myself if possible, but if I can't I am wondering if I can replace the motherboard, part number ZAM71 LA-A903P(the bad one I have with the i7), with a ZAM70 LA-A901P(i3 or i5 I think). Also can i take out the i7 CPU and put that in the ZAM70 LA-A901P board? Thank you guys in advance.

[vannix]

Re: Dell Latitude E5450 Power Short Circuit

ONLY for ZAM71:
To solve this problem you have check and replace the four capacitor near PQ704/PQ700 (PC714/15/16/17). Only one will be short, but I advise you to change them all.
Then, if needed, check and replace PQ4 (P-channel mosfet) which can be broken by the short circuit.

[titomno2]

Re: Dell Latitude E5450 Power Short Circuit

Hello guys,
Seems we are a lot with the same damn issue with this motherboard (and stock out of spare parts from dell support indicates that this seems to be a bad patch of component).
Whatever I have once with the same issue short circuit, I was able to discover that one component begin to be very hot if I inject some current with stabilized power supply (1.1V and 3Amps) the component is sop8 4435 (PQ700) that begin to be very hot, I have some question regarding the PQ4 that present some strange aspect.
May be the hot PQ700 is due to improper trigger from PQ4, may the PQ4 be defective.
All these elements are near processor heat pipe and I wonder if they are not submitted to too much heat.

So if any of you have some advice, I will be very gratefull (I checked all caps, and did not see short or overheating when injecting current).

Have a nice day and thanks for your help.

Stay safe.

[ESLAM9K]

Re: Dell Latitude E5450 Power Short Circuit

Fuck same issue

[rbvndonh]

Re: Dell Latitude E5450 Power Short Circuit

Anyone have a solution? Is it true, that APU are dead in this mother boards?

[facarr]

Re: Dell Latitude E5450 Power Short Circuit

Have to check, all ceramics CAPs, normally someone have shortcut, have to change it

[ACS-Repair]

Re: Dell Latitude E5450 Power Short Circuit

The LED on the power adapter turning off is telling you that there is an input short and the power supply is shutting down to protect itself. Follow the wires from the input jack to the motherboard and check for a short there. You can unplug that connector and reconnect your adapter to see if the power supply is still shutting down. If the LED stays on, there is a short on the motherboard close to where that cable connects. Otherwise you're looking at a problem with the jack. I've seen this a few times before.

[ACS-Repair]

Re: Dell Latitude E5450 Power Short Circuit

I should mention that there is an over-voltage protection diode on the input that is quite often the culprit in this case. Check that first.

[titomno2]

Re: Dell Latitude E5450 Power Short Circuit

Hello Guys,
After receiveing some new toys (thermal camera and power suplly).
I have injected with power supply 1.2V and the motherboard drained around 5 amps.
With thermal camera I found a bad cap heating near PQ705, once removed with hot air gun, the short disappared and now the motherboard is working again.
I have a donor motherboard to swap badcaps (I have removed also another short circuit on this one but the issue was obvious (cap exploded)) => fixed short circuit but can't use the motherboard because previous owner destroyed the bios chip UC2 (pads are completely out of the motherboard).

I use FLIR TG267 (MSX is sometimes hard to see the good component because of misalignement between HD cam and Flirt cam, but hiding the HD cam with finger help to see only FLIR vision).
Hope it could help some of you.

Best Regards and take care.

[Blitzbirnle]

Re: Dell Latitude E5450 Power Short Circuit

Hello Guys,

I have a following problem with my DEll Latitude E5450 with Motherboard LA9412F Rev1.0:

The problem is that the notebook goes on for about 3 seconds and then switches off immediately. The LED turns on and the fan spins. If I remove the RAM, the notebook stays on...

I've already flashed the BIOS and changed the RAM several times. And I've already changed the CPU too.

Does anybody has an advise?

[Blitzbirnle]

Re: Dell Latitude E5450 Power Short Circuit

Hello Guys,

I have a following problem with my DEll Latitude E5450 with Motherboard LA9412F Rev1.0:

The problem is that the notebook goes on for about 3 seconds and then switches off immediately. The LED turns on and the fan spins. If I remove the RAM, the notebook stays on...

I've already flashed the BIOS and changed the RAM several times. And I've already changed the CPU too.

Does anybody has an advise?

Doesn't anyone have a solution?