Dell E6430 shortcircuit

[Andreasbest]

Hello!
I received one E6430 that has a shortcircuit, when i plug the charger in it, the charger turns off. Must unplug and plug from mains to make charger work again.
Any ideas???
Thank you in advance!!

[Sametbey]

Re: Dell E6430 shortcircuit

Check DC_IN input on page 44 and PQ1300 mosfet on page 52. Check if there is a short circuit on the Pr1301 shunt resistor. Good works.

[Andreasbest]

Re: Dell E6430 shortcircuit

Check DC_IN input on page 44 and PQ1300 mosfet on page 52. Check if there is a short circuit on the Pr1301 shunt resistor. Good works.

Just to mention i found shortcircuit to ground in PQ914, pins 1 2 3 & 4 (pin 4 is already ground anyway) soldered and unsoldered.
Is that change what you told me before??

[Sametbey]

Re: Dell E6430 shortcircuit

If there is a short circuit on the 1 2 3 pins of the PQ914, there may be a short circuit on the 19v line of the motherboard. like nf capacitor.

[Andreasbest]

Re: Dell E6430 shortcircuit

If there is a short circuit on the 1 2 3 pins of the PQ914, there may be a short circuit on the 19v line of the motherboard. like nf capacitor.

Can you show me please?

[Spider1211]

Re: Dell E6430 shortcircuit

Just to mention i found shortcircuit to ground in PQ914, pins 1 2 3 & 4 (pin 4 is already ground anyway) soldered and unsoldered.

Pin 4 of PQ914 should not be grounded. Remove PQ914 and check again. Usually short on main rain is due mostly because of shorted caps (those brown little bricks).

Do you have a microscope or a good magnifying lens? Before removing any parts, do a close visual check with special attention to those little brown caps. If you find any that is cracked/missing part of the brown part or looks very discolored, its most likely the culprit. Remove it and check if your short is gone.

[Andreasbest]

Re: Dell E6430 shortcircuit

Pin 4 of PQ914 should not be grounded. Remove PQ914 and check again. Usually short on main rain is due mostly because of shorted caps (those brown little bricks).

Do you have a microscope or a good magnifying lens? Before removing any parts, do a close visual check with special attention to those little brown caps. If you find any that is cracked/missing part of the brown part or looks very discolored, its most likely the culprit. Remove it and check if your short is gone.

My mistake, pin 4 is not grounded.

[Spider1211]

Re: Dell E6430 shortcircuit

OK good. I wont worry about PQ914 yet though. If you want, remove it and check if the short is still there (pretty sure it'll still be). Then look for the shorted caps as mentioned above.

[Andreasbest]

Re: Dell E6430 shortcircuit

OK good. I wont worry about PQ914 yet though. If you want, remove it and check if the short is still there (pretty sure it'll still be). Then look for the shorted caps as mentioned above.

Problem is all capacitors on the top left (DC_IN area) are all grounded.
Can't desolder them all to test and none is discolored or cracked, i searched before opening the thread.

[Spider1211]

Re: Dell E6430 shortcircuit

Look throughout the board and on both sides, not just the DC_IN area.

[Andreasbest]

Re: Dell E6430 shortcircuit

Perhaps it's better to open the jumpers one by one until i notify the shortcircuit is gone.

[Spider1211]

Re: Dell E6430 shortcircuit

You could do that also but will take a bit more time. Or if you have a bench power supply, you can inject voltage. Start at 1V 1A, then increase the AMP only slowly until you find something getting hot.

[Andreasbest]

Re: Dell E6430 shortcircuit

Yes i was thinking that after the jumpers.
Tell me something, all these under CPU socket are C or PL?? (except the black cap in the middle)

[Spider1211]

Re: Dell E6430 shortcircuit

Remove the white-ish plastic cover. The parts should be labelled, but judging from the shape outline in your picture it looks like a capacitor (C).

[Andreasbest]

Re: Dell E6430 shortcircuit

Unfortunately they are not labeled.
I open the jumpers and i only see shortcircuit now on the very top left dcin area and in this under cpu area.
That's why i want to know if they are c or pl.

[Spider1211]

Re: Dell E6430 shortcircuit

It is actually labelled, Capacitors are sometimes also labelled as "PC". In your case that would be PC1077. And no, I don't think its a short circuit. Measure its resistance and report back. +VCC_Core will have a low resistance because of the CPU.

Also, post a picture similar to post #13 but without the plastic, I saw a cap that looks a bit odd (not sure if its because of reflection, glue or dirt). Maybe you could take a closer look.

Edit:
Nevermind, the capacitor is not present looking at picture in post #15.

[Andreasbest]

Re: Dell E6430 shortcircuit

It is actually labelled, Capacitors are sometimes also labelled as "PC". In your case that would be PC1077. And no, I don't think its a short circuit. Measure its resistance and report back. +VCC_Core will have a low resistance because of the CPU.

Also, post a picture similar to post #13 but without the plastic, I saw a cap that looks a bit odd (not sure if its because of reflection, glue or dirt). Maybe you could take a closer look.

Edit:
Nevermind, the capacitor is not present looking at picture in post #15.

Resistance in all capacitors there is 3.2Ω
PC1077 in the center is tantalum cap, i know. I meant about all these around it, are these caps too?

[Spider1211]

Re: Dell E6430 shortcircuit

Just make sure you are factoring in your probe resistance. Short your probes together and check its resistance value (should be 0).

Otherwise 3.2 seems fine for CPU. If your CPU is socketed remove it and measure again, it should be a much higher resistance value.

[Andreasbest]

Re: Dell E6430 shortcircuit

yes with probes short i get 0.05Ω.

Without CPU i get 3.22KΩ, much higher indeed
Now without pjp601, pjp1301 and pjp702 i get the shortcircuit only in top left dcin area.
Pins 1 2 and 3 of PQ914 to be more precise.

[Spider1211]

Re: Dell E6430 shortcircuit

Don't remove Jumpers blindly. By the looks of it, you have a short on 19V rails (system side) [Assuming you removed PQ914 and pin 5 to 8 is not shorted to ground].

The shorted rail is named +PWR_SRC. Jumpers are usually present when another 'section' of the board need 19V to convert it to something else, as is the case with PJP702 where the 19V will be converted to +VCC_GFXCORE.

Removing jumpers to find shorts is only really helpful to figure out which 'section' is faulty/shorted but is useless if the fault is on +PWR_SRC.

Think of it like this:
Imagine you have an underground main water pipe that feeds say 5 houses. Each house gets water from the main pipe through a vane/valve (which in your case is the jumper).

Now say you get a complaint that water is leaking. You could eliminate leaks through the houses by closing the water vane/valve for each house.

But there is also the other possibility that the leak is coming from the main pipe itself in which case closing the valve/vane would not be helpful since the leak could be anywhere along said pipe. In such cases you might maybe inject a marker in the water and use a detector to locate the leak (which in your case is analogous to injecting voltage and feel for what gets hot).

Hope that somewhat helps.

Coming back on topic, if you cannot find anything wrong visually I suggest you inject voltage and locate what gets hot.