DELL Latitude E6520 płyta: LA-6563P - Nie wykrywa zasilacza.

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Komputer: Dell Latitude E6520
Płyta Główna: LA-6563P Rev 1
CPU: SR03F Intel i7-2620M
GPU: N12P-NS-S-A1
Chipset: BD82QM67 SLJ4M
KBC: SMSC MEC5055

Usterka: Laptop nie wykrywa ładowarki, przez co nie ładuje baterii.

Zasilacze jakie mam to oryginały Della i w innym delu wykrywane są prawidłowo.
Bateria 100% dobra, nowa z pudełka.
Nie posiadam schematu.
Na płycie głównej znalazłem spalone dwa elementy PQ3, PQ2 nie da się z nich odczytać marking code. Prosił bym kolegów o identyfikację tych dwóch tranzystorów.

Pomiary oporności na PQ3 po demontażu:
1-15kOhm i rośnie
2- 14,93 Kohm
3- 1,3 Ohm ale taką to mają rezystancje moje kable pomiarowe

Pomiary oporności na PQ2 po demontażu:
1- 114,7 kOhm
2- 13 kOhm i rośnie
3- 8kOhm i rośnie

I tutaj moje pytanie do bardziej doświadczonych, oporności wydają się być poprawne - więc co mogło spowodować uszkodzenie tych dwóch tranzystorów.

I kolejne pytanie po wlucie tranzystorów mogę już testować czy ładowanie wróciło czy na coś jeszcze powinienem zwrócić uwagę?

Hello!

Such damage is usually caused by damaged DC socket or damaged DC cable on the power supply.

The resistance measurements seems ok.
Also measure the resistances to ground on pins 3, 4 of chip PU1.

Damaged transistors should be as follows:
PQ2= FDV301N
PQ3= MMST3904

Matic thank you for answer.

PU1 have J7R marking code i dont find datashit for this ic in internet.
I did measurement resistance for PU1 IC and measurement result look good.
Pin 1- Resistance is OL,
Pin 2- 1,6 Ohm but this resistance have my measurement cables,
Pin 3- 5,5 kOhm and resistance grow up,
Pin 4- 30 Mohm
Pin 5- 2 kOhm and resistance grow up,
Pin 6- 19,61 Mohm.

I dont know what this IC do, becouse i dont find datasheet for this ic, but i think measurments result look good.

What you think about this?
In my country I was looking for PQ2 and PQ3 transistors and I did not find them do you know any replacements?

Ok i found FDV301N. But the MMST3904 transistor was not available for sale in our country.

Pierun napisał(a):PU1 have J7R marking code i dont find datashit for this ic in internet.

PU1 is analog switch IC (J7R marking = TS5A63157DCKR).
The resistances on PU1 seems ok; PU1 is probably ok.

Pierun napisał(a):In my country I was looking for PQ2 and PQ3 transistors and I did not find them do you know any replacements?

Transistors PQ2 and PQ3 are not critical, there are many replacements available. Do you have any old scrap boards (best from dell laptops)? If so, specify the boards marking codes; you may find the appropriate replacements on them.

Also check the following components:
- Resistor PR9 (33Ω/5%, package 0402)
- Coil PL2 (check, if it is not interrupted)
- Diode PD6 (Dual diode DA204U)
- Diode PD7 (Suppressor diode SM24)

There is no PD7 in this motherboard. PD6 is good is not damaged conducts current in one direction. PL2 is also good. But where is PR9? Resistors is'nt marking on this board. Im not sure, but i loking PR9 near PQ2 and PQ3 i found two resistor, first resistor is connect to source pin PQ2 and resistance this resistor is 1,82 kOhm. Second resistor is connect to Gate pin PQ2 and resistance this resistor is 9,97 kOhm. Resistors look good under microscope. I measure resistance this resistors after desoldering them.

If I'm not mistaken the resistor PR9 should be the highlighted one:


One pin of this resistor should be connected to pin "S" of PQ2, onother pin should be connected to pin 3 of chip PU1.
If so, this resistor is damaged and should be replaced.

Matic, you typing is correct! This is PR9. First pin PR9 is connect to Source PQ2 and second pin PR9 is connect to 3 pin PU1. Did you have any damaged resistors this way? I first met with the fact that a damaged resistor has a much higher resistance than it should. OK resistor I replaced. I am still looking in my damaged motherboards for transistors corresponding to PQ2 and PQ3.

Pierun napisał(a):Did you have any damaged resistors this way?

Yes, of course.
When the resistor goes bad, his resistance usually increase significantly, or the resistor goes to open circuit. Depending on the type of overload.

Ok Matic, i would like to thank you. Problem witch this motherboard has been resolved. Thank you. He helped already click

Summarizing the problem of this vulnerability:

The problem was probably caused by a damaged charger cable or power socket.
The PR9 resistor and PQ2 and PQ3 transistors have been damaged on the motherboard.