Dell E5550 No charge (charger unidentified)

[Andreasbest]

hello.
I have a Dell E5550 that doesn't recognize the charger, the usual Dell problem, i tried multiple chargers that charge fine other Dell laptops so the issue is clearly in mainboard.
I replaced the PQ2 and PQ3 but no luck, so i need your help on what to do next.
Schematics attached.
Thank you in advance

[SMDFlea]

Re: Dell E5550 No charge (charger unidentified)

Check PR9 resistance and voltage

[Andreasbest]

Re: Dell E5550 No charge (charger unidentified)

Check PR9 resistance and voltage

5v in both pins of PR9

[SMDFlea]

Re: Dell E5550 No charge (charger unidentified)

5v in both pins of PR9

Measure the voltage on PU1 next

[Andreasbest]

Re: Dell E5550 No charge (charger unidentified)

Measure the voltage on PU1 next

Goodmorning, sorry for the delay i was away from lab.
PU1
pin1 0v
pin2 0v
pin3 0.66v
pin4 0v
pin5 5v
pin6 0v

[Vesko356]

Re: Dell E5550 No charge (charger unidentified)

5v in both pins of PR9

Goodmorning, sorry for the delay i was away from lab.
PU1
pin1 0v
pin2 0v
pin3 0.66v
pin4 0v
pin5 5v
pin6 0v

Pin3 is directly connected to PR9, so check again - I mean the voltage on PR9 and pin3 of the PU1 must be the same. Also check resistance to ground in the line.

----> Look here. The diode marking for your board is PD5, the rest is the same.

[Andreasbest]

Re: Dell E5550 No charge (charger unidentified)

To avoid any confusion please show me which one is PR9 as there is no writing, just to be 100% i'm measuring correctly

[SMDFlea]

Re: Dell E5550 No charge (charger unidentified)

To avoid any confusion please show me which one is PR9 as there is no writing, just to be 100% i'm measuring correctly

Just posted the boardview - https://www.badcaps.net/forum/showthread.php?t=67214

[Andreasbest]

Re: Dell E5550 No charge (charger unidentified)

Just posted the boardview - https://www.badcaps.net/forum/showthread.php?t=67214

Can't open it, boardviewer and openboardview crash when i attempt to open it

[SMDFlea]

Re: Dell E5550 No charge (charger unidentified)

Can't open it, boardviewer and openboardview crash when i attempt to open it

It opens ok for me with BoardViewer, make sure you have the latest version -

http://boardviewer.net/

[Andreasbest]

Re: Dell E5550 No charge (charger unidentified)

Yes i do (version 1.2)
Probably the problem is in my Windows 7, perhaps NET framework is missing or something, i'll try on Windows 10 laptop.

[Vesko356]

Re: Dell E5550 No charge (charger unidentified)

To avoid any confusion please show me which one is PR9 as there is no writing, just to be 100% i'm measuring correctly

Look the arrows.

[Andreasbest]

Re: Dell E5550 No charge (charger unidentified)

Look the arrows.

Yes i can confirm pin 3 and 5 have both 5v. (not sure why i measured 0.66 before @ pin3)

[Vesko356]

Re: Dell E5550 No charge (charger unidentified)

Yes i can confirm pin 3 and 5 have both 5v. (not sure why i measured 0.66 before @ pin3)

Just ignore the voltage,Check continuity between NB_PSID and PS_ID.


Multimeter in resistance or diode mode, one probe to point1, and with the other probe check continuity between point1 and poin2, and point1 and point3.

Also check resistance in ohms between point1 to ground, and point3 to ground.

[Andreasbest]

Re: Dell E5550 No charge (charger unidentified)

Just ignore the voltage,Check continuity between NB_PSID and PS_ID.


Multimeter in resistance or diode mode, one probe to point1, and with the other probe check continuity between point1 and poin2, and point1 and point3.

Also check resistance in ohms between point1 to ground, and point3 to ground.

No continuity between PL3 and pin 3 and 4 of PU1.
PU1 pin 4 to ground ~1Ω
PL3 to ground ~115kΩ

[Vesko356]

Re: Dell E5550 No charge (charger unidentified)

No continuity between PL3 and pin 3 and 4 of PU1.
PU1 pin 4 to ground ~1Ω
PL3 to ground ~115kΩ

PU1 pin 3 to ground is...?
Pin 4 to ground 1Ω...? So PU1 is most probably defected, unsolder PU1 from the board, and repeat the measurements (with and without the charger connected).

[Andreasbest]

Re: Dell E5550 No charge (charger unidentified)

PU1 pin 3 to ground is...?
Pin 4 to ground 1Ω...? So PU1 is most probably defected, unsolder PU1 from the board, and repeat the measurements (with and without the charger connected).

PU3 to ground ~3kΩ
Desoldered pin4 to ground ~45MΩ

[Vesko356]

Re: Dell E5550 No charge (charger unidentified)

PU3 to ground ~3kΩ
Desoldering now

OK, waiting for new data.

[Andreasbest]

Re: Dell E5550 No charge (charger unidentified)

OK, waiting for new data.

Desoldered pin4 to ground ~45MΩ

[Vesko356]

Re: Dell E5550 No charge (charger unidentified)

Desoldered pin4 to ground ~45MΩ

Excellent, so PU1 is defective 100%, take new measurements and reply.

-----> PL3 countinuity to PU1 pin3 with, and without charger????