Dell inspirion n5110 Po zalaniu

Witam serdecznie.
Kupiłem nie sprawnego (całkiem martwy) laptopa w celu jego naprawy, po wyjęciu płyty okazało się że laptop był zalany, co prawda ktoś wcześniej wyczyścił płytę jednak pod mikroskopem widać ślady zalania.
Płyta główna. DQ15 DN15 (0G8RW1 REV: A01)
Trafił
Początkowo było brak wszystkich napięć na cewkach, po wymianie przetwornicy "PU4103", rezystora "PR4111" i kondensatora "PC4104" pojawiły się napięcia na cewkach:
PL4101- 3V
PL4102- 5V
PL4601- 1.5V
Po podłączeniu zasilania plyta się włączą samoczynnie lecz nie można jej wyłączyć, po naduszeniu POWER gaśnie na chwilkę dioda i nic więcej się nie dzieje.
Płyta bez ramu pobiera 20mA
A z pamięcią 100mA
Doszedłem do tego że brak jest napięcia "0D75V_DDR_P" na "PU4601" idąc tym krokiem doszedłem do "q3602" na którym brak jest napięcia "3D3V_AUX_S5" niestety nie moge zlokalizować "R3606" i "PG4125"

Czy w ogóle idę w dobrym kierunku?

Kalmar11 ha scritto:którym brak jest napięcia "3D3V_AUX_S5"

Hello!

"3D3V_AUX_S5" is generated by PU4103.
Measure voltages to ground on pins 8, 16 and 17 of PU4103. If there is no voltages on pins 8 and 17, measure resistances to ground on this two pins.

yes i know. PU4103 works well. All voltages are present. That's why I'm looking for the R3606

Ok.

Specify voltages to ground on pins 2, 3, 5, 6, 9, 16 and 17 of PU4601.

Measure voltages to ground on all pins of Q3602 and Q3704.

Hi. What is the converter for you? I ask because I see that in different schemes they are differently marked. Do you mean the 1.5V and 0.75V converters?

I look at the schematic: Wistron Queen 15, Rev.: A00
This one: ***click***

According to the schematic:
PU4601 = TPS51216 (20-pin QFN package)
Q3602 = 2N7002KDW (6-pin SOT363 package)
Q3704 = 2N7002K (3-pin SOT23 package)

gives the voltage.
PU4601
2-1.5V
3-0.19V
5-0.76V
6-1.8V
9-1.5V
16-3.3V
17-0V

Q3602
1-0V
2-3.36V
3-0V
4-0V
5-0V
6-0V

Q3704
1-0V
2-0V
3-0V


As I wrote in the beginning, I can not find R3606 and PG4125

3.3V and 5V on pins 8 and 17 of PU4103 present?

Yes, voltages are present. I noticed that when I press POWER, 3.3V appears on pin 1 Q3704. Should the voltage at pin 3 Q3704 also appear at this time?

Kalmar11 ha scritto:I noticed that when I press POWER, 3.3V appears on pin 1 Q3704. Should the voltage at pin 3 Q3704 also appear at this time?

When the logic "1" (3.3V) appears on pin 1 of Q3704, voltage on pin 3 of it should be 0V and the other way around (in assuming that the PU4501 runs ok).


Measure voltages to ground on pin 1 of diode PD4101 and on pin 2 of diode PD4103 after pressing on the power button.

PD4101
Pin1- 5V

PD4103
Pin2- 15V

Voltage does not change when you press POWER

Measure resistances to ground on pin 3 of Q3602 and on pin 3 of Q3704.

Q3602
Pin3- The multimeter has not detected the resistance

Q3704
Pin3- 10.75kΩ

Measure voltages to ground on both pins of resistor R3604.

No voltage on the resistor "R3604", only after pressing the POWER button for a while appears 40mV on both sides of the resistor

One pin of resistor R3604 should be connected to pin 3 of transistor Q3602, and another pin should be connected to pin 2 of diode PD4103 through jumper PG4104.

Use continuity tester, and check connections of this resistor. The corrosion is probably damaged paths on the PCB.
If the path is broken use thin wire, and bridge it.

you were right. There was no connection between "PD4104" and Pin2 "PD4103" and between "PG4101" and "R3604". Now the motherboard turns on and off by pressing the POWER button. The current is up to 700mA and drops to 400mA.

Kalmar11 ha scritto:Now the motherboard turns on and off by pressing the POWER button. The current is up to 700mA and drops to 400mA.

So, what is the issue now? No picture? Does the laptop stays turned ON?

yes, the laptop turns on without a picture. I tested on different RAM and CPU.

Check, if you get picture on external monitor via D-sub or HDMI port.

If there is no picture on external monitor, measure voltages to ground on all coils.