Dell Precision 3510 completely dead

[Andreasbest]

Re: Dell Precision 3510 completely dead

I removed QV1 but no change at all, resistance still low

[Spider1211]

Re: Dell Precision 3510 completely dead

Search schematic for +PWR_SRC and open respective jumpers, the measure resistance as you go. Injecting voltage is not recommended since we don't know where the fault is and would thus need to keep voltage low, which means current will also be low and nothing will get hot.

Try removing PU603 also although it should not make any difference since PL602 has been removed. Make sure the pad for PU602 is clear of any soot by the way.

[Andreasbest]

Re: Dell Precision 3510 completely dead

PU603 is difficult to remove because the solder is underneath it.
I'll follow +PWR_SRC and remove the jumpers.

[Andreasbest]

Re: Dell Precision 3510 completely dead

Goodmorning!
I open all jumpers i saw @ +PWR_SRC, these are:
100
101
202
402
601
but the resistance between pin 1 of PU602 and ground is still ~4Ω

What do you thing?

[Spider1211]

Re: Dell Precision 3510 completely dead

PU602 or PL602? If its 4ohms you can try injecting voltage. Do not go above 1.5V and see what gets warm/hot.

[Andreasbest]

Re: Dell Precision 3510 completely dead

PU602, the burnt MOSFET.
Injection from pin 1 and ground, correct?

[Spider1211]

Re: Dell Precision 3510 completely dead

pin 1 as in ZCD_EN#? which comes from FCCM_VCORE

[Spider1211]

Re: Dell Precision 3510 completely dead

To avoid confusion, measure resistance on all pins of PU602 and report back.

[Andreasbest]

Re: Dell Precision 3510 completely dead

To avoid confusion, measure resistance on all pins of PU602 and report back.

Here, measured everything with the ground (except the GND pins)

[Sephir0th]

Re: Dell Precision 3510 completely dead

Why Not Remove PU603 to confirm the short of the Power Rail between PL602 and VIN of the PowerStages?

[Andreasbest]

Re: Dell Precision 3510 completely dead

I will i'm just trying to avoid it but i will if i have to.
Has bottom solder, that's why i'm trying to avoid it.

[Sephir0th]

Re: Dell Precision 3510 completely dead

You also have to solder the replacement IC Back too, ofc course Only If we can get rid of the short(s).

So i don't see the Point to Work around. Most likely Burned layers are welded to together and CPU Fried too, but who Knows. There could be a Chance...

[Andreasbest]

Re: Dell Precision 3510 completely dead

I'm afraid of that too but since i have 5x mosfet i can give it a try and hope.
Plus it has Xeon cpu, if it was a i5 or i3 i wouldn't bother

[Spider1211]

Re: Dell Precision 3510 completely dead

Practice on a donor board if needed. Removing components and testing is safer than injecting voltage. I'ld also remove PL603 and PL604 to isolate +VCC_CORE and check for short again. It also decreases the risk of accidentally sending unsafe voltage to the CPU.

In any case, I strongly suggest you tune in you soldering skills on donor boards if you do not feel very confident yet.

[Andreasbest]

Re: Dell Precision 3510 completely dead

Practice on a donor board if needed. Removing components and testing is safer than injecting voltage. I'ld also remove PL603 and PL604 to isolate +VCC_CORE and check for short again. It also decreases the risk of accidentally sending unsafe voltage to the CPU.

In any case, I strongly suggest you tune in you soldering skills on donor boards if you do not feel very confident yet.

Hello!
I removed the PU603 but the shortcircuit was still there.
I appied 1w from bench psu and while i was searching for shorts the short gone, now Vin to Ground is 40MΩ
The short in Vswh remains though.
What do you think?

[Spider1211]

Re: Dell Precision 3510 completely dead

What voltage did you apply when finding the short and where did you apply it? You most likely burnt out the short .

What is the resistance value of VSWH?
VSWH goes to +VCC_CORE which is CPU core voltage and therefore having a low resistance is normal.

If you remove PL603 and PL604, you should only read low resistance on pin 1 and 2. Pin 3 and 4 should read open circuit.

[Andreasbest]

Re: Dell Precision 3510 completely dead

What voltage did you apply when finding the short and where did you apply it? You most likely burnt out the short .

What is the resistance value of VSWH?
VSWH goes to +VCC_CORE which is CPU core voltage and therefore having a low resistance is normal.

If you remove PL603 and PL604, you should only read low resistance on pin 1 and 2. Pin 3 and 4 should read open circuit.

Ι applied 1v 1A & 2v 1A, not sure when the short burnt, i noticed it right after 2v 1a.
Vswh resistance to ground is 3.5Ω
Just removed both PL. I'll sent measurements in a few mins

[Andreasbest]

Re: Dell Precision 3510 completely dead

pin1 4.3Ω
pin2 0.5Ω
pin3 NC
pin4 inf.
pin5 inf.

(all measurements before the SMD)

[Spider1211]

Re: Dell Precision 3510 completely dead

Vswh resistance to ground is 3.5Ω

This should be fine.

pin1 4.3Ω
pin2 0.5Ω
pin3 NC
pin4 inf.
pin5 inf.

(all measurements before the SMD)

Where were those measurements taken? PU602/PU603? What do you mean by 'before SMD'?

Pin 1 and 2 does not look good. Pin 2 (assuming you meant VCIN of PU602/603) is indicating a short on +5V_RUN and pin 1 (ZCD_EN#) could be due to a faulty PU601. Try removing PU601 and measure again.

If you remove PL603 and PL604, you should only read low resistance on pin 1 and 2. Pin 3 and 4 should read open circuit.

I was referring to pin 1,2,3 and 4 of PL603/604 by the way.

[Andreasbest]

Re: Dell Precision 3510 completely dead

This should be fine.




Where were those measurements taken? PU602/PU603? What do you mean by 'before SMD'?

Pin 1 and 2 does not look good. Pin 2 (assuming you meant VCIN of PU602/603) is indicating a short on +5V_RUN and pin 1 (ZCD_EN#) could be due to a faulty PU601. Try removing PU601 and measure again.



I was referring to pin 1,2,3 and 4 of PL603/604 by the way.

measurements taken on PU602, one probe on the side towards MB (not side towards burnt PU602) and the other on GND.
For some strange reason i can't find PU601 (please check attachment)
PL603 and PL604 have only 2 pins.