Dell Inspiring 15R

[dspok]

There was short circuit, replaced PC4114 and PU3801, short circuit gone.

Now PU4103 is overheating no 3.3v or 5v, power button 1.8v, PL4501 is ground. Lifted PL4501 still PU4103 is overheating. Changed PU4103 still overheating. PL4101 0.800kohm, PL4102 37.00kohm to ground.

Somebody please help to solve this problem.

[ganeshcell]

Re: Dell Inspiring 15R

change PU4501.if not solved then ur BD82HM67 is short.

[dspok]

Re: Dell Inspiring 15R

PU4501 seems to be good, but strange that I found short at C2709, C2710, C2701 and C2708 of SIO chip. And are you sure PCH is dead?

[BlueMidnight]

Re: Dell Inspiring 15R

PU4103 (like pretty much any 3/5V regulator chip used in notebooks) has 4 main voltage output rails: 3.3V/5V linear regulator (LDO) outputs and 3.3V/5V switch mode (buck converter) outputs.

1) Recheck 3.3/5V rails for shorts. Make sure the voltmeter is in diode mode. Red probe on ground and black probe on the pin you are testing.
2) Check the 3.3V and 5V LDO rails for shorts (PU4103 pins 8 & 17). C2709, C2710, etc. are on the 3.3V LDO rail, so it sounds like you may have already found a short there. That will definitely overheat PU4103 because it's not smart enough to shut off an LDO output that is shorted.
3) The original short also went through PU4002, so it's best to replace that too after fixing everything else. Just for the sake of reliability.

If you find a short, then you'll have to isolate sections of the board and see if the short goes away. For example, you can remove Q2703 to disconnect the EC/KBC/SIO (whatever you want to call it) area.

[dspok]

Re: Dell Inspiring 15R

Thanks @BlueMidnight

No short on 3.3 or 5v, diode mode from gnd shows voltage. No short on pin8, pin17 of PU4103, C2709, C2710 shows full short. PU4002 is working correctly. I have no idea how to be sure to find out the faulty component.

[BlueMidnight]

Re: Dell Inspiring 15R

Q2703 starts in the off state. So if there is a short near the SIO, you will read a short on one side and no short on the other. But if the board is powered up, that FET turns on, and now PU4103 is shorted to ground on pin 8. If you remove Q2703 you can make sure PU4103 doesn't get hot anymore.

The odds are that the SIO is bad. It's the most delicate thing there. But it's not 100% certain.

You can remove everything connected between 3.3V and ground until the short is gone. Start with the SIO or start with the stuff that's easier to solder. Your choice.

Otherwise, you could inject a higher current at 3.3V with a current-controlled bench PSU and see what gets hot. But if it's the SIO, it might not get hot.

PU4002 should be replaced, not because it's failed already, but because the short sent a high current through both PU3801 and PU4002. They are exactly the same part number. If a current is high enough to damage one, it is high enough to damage the other. Even if you don't notice it yet.

[dspok]

Re: Dell Inspiring 15R

After removing Q2703, found PU4103 isn't going hot and PL4101, PL4102 have 3.3v, 5v respectively.
Injecting 3v to C2709, SIO gets hot and injecting 3v to PL4101, consumes current but nothing gets hot.

[BlueMidnight]

Re: Dell Inspiring 15R

Good, that's progress. Unfortunately it looks like the SIO is bad and needs to be replaced. You can make sure the short is gone after removing it. The good news is that it stores its firmware on the same external flash IC that the PCH does. So, you won't have to program the new chip.

[dspok]

Re: Dell Inspiring 15R

Good, that's progress. Unfortunately it looks like the SIO is bad and needs to be replaced. You can make sure the short is gone after removing it. The good news is that it stores its firmware on the same external flash IC that the PCH does. So, you won't have to program the new chip.

Thank you,
Short is gone on C2709 , C2710 but I can't find NPCE795PA0DX in my stock, is NPCE795LA0DX compatible with it?

[BlueMidnight]

Re: Dell Inspiring 15R

Hmm I honestly don't know. They make it almost impossible to find datasheets for those. But I can find them for purchase online and sometimes they list the 795L, 795P, 795G, and 791G in the same description. So, if I trust that, it means that all 4 of those are compatible.

[dspok]

Re: Dell Inspiring 15R

Changed SIO, laptop turns on with 3 beeps. Looks like PCH is dead.

[ridamouh159]

Re: Dell Inspiring 15R

your kbc is good or new ؟
if yes you must to take off and solder good -all pins-
or change it

[dspok]

Re: Dell Inspiring 15R

your kbc is good or new ؟
if yes you must to take off and solder good -all pins-
or change it

KBC new @ridamouh, all pins were good but I will look into it again.
Thanks btw.

[dspok]

Re: Dell Inspiring 15R

@ridamouh
You were right, thanks everybody specially @BlueMidnight

[BlueMidnight]

Re: Dell Inspiring 15R

Glad to help. Great work