Laptop ACER A315-51-52TW po zalaniu nie uruchamia się

PU5 :
1:5.19V
3:3.28V
4:5.19V
5:3.28V
7:5.19V
8:0V
14:0.62V

PU8:
1:3.42V
3:3.28V
4:5.19V
5; 3.28V
7:3.42V
8:3.42V
14:3.42V

Czy PU5 nie powinien podawać 5V jeśli dostał sygnał ON na pin 3 i pin 5?
Oryginalnie wmontowany jest układ z oznaczeniem: 22976 TI 788 A48V
Wymieniałem już kilkakrotnie PU5 ale dalej brak jest napięć na VOUT1 i OUT2.

terabajt ha scritto:Czy PU5 nie powinien podawać 5V jeśli dostał sygnał ON na pin 3 i pin 5?

Yes, it should.
Measure the resistances to ground on pins 8, 14 of PU5.

terabajt ha scritto:Oryginalnie wmontowany jest układ z oznaczeniem: 22976 TI 788 A48V

Please, post a clear picture with visible markings on chips PU5, PU8.

Pu5
PIN 8: 4 MOhm
PIN 13: 0.303 MOHM
PU5 PO WYMIANIE:


PU8 oryginalny (taki sam był PU5)

Okay, original chip is TPS22976, the replacement one is AOZ1331DI.

Switch the chips PU5 and PU8 - solder the original chip TPS22976 to the place of PU5 and place replacement chip AOZ1331DI to the place of PU8.
After that remeasure the voltages to ground on both chips as suggested in post #101.

PU5
1:5.19 V
3: 3.29V
4: 5.19V
5:0V
7:5.19V
8:0V
14:0V
PU8:
1:3.42V
3:3.29V
4:5.19V
5:0V
7:3.42V
8:0V
14:0V

Check your solder joints on all pins of both chips.
Measure the resistances to ground on pins 10, 12 of PU5, PU8.

ok, now:
PU5
1:5.19 V
3: 3.29V
4: 5.19V
5:3.28V
7:5.19V
8:0V
14:0V
PU8:
1:3.42V
3:3.29V
4:5.19V
5:3.28V
7:3.42V
8:3.42V
14:3.42V

PU5
pin 10: 6.98MOhm
Pin 12: 6.79 MOhm
PU8
Pin 10: 43 MOhm
Pin 12: 43 MOhm

Now you have the replacement chip (marking AY0A) on the place of PU8?

Are you 100% sure that the solder joints on all pins of PU5 are okay?

Yes, on PU8 is AY0A.
On PU 5 is oryginal chip .
Yes, all pins on PU5 are ok solder

Measure the resistances to ground on pins 8, 14 of PU5.
Measure the voltages to ground on pins 10, 12 of PU5.

PU5 after discharged to The ground:
PIN 8: 2.5 MOhm
PIN 14:10.3 KOhm
PIN 10: 0v
PIN 12:0v

By the way, you lost the capacitor PC103 near the PU5. It is not related to the missing voltages on the PU5 outputs, but solder it back anyway. Value of this capacitor is 1µF/25V, package 0402.




Open (cut) the jumpers PR127 and PR128 (highlighted on the following picture). Check, if the voltages on pins 8, 14 of PU5 occurs with opened jumpers.
The board is multi layer, so be careful to not cut too deep (cut the top copper layer only).

After cut the jumpers PR127 and PR128 on pin 8, 14 of PU5 is still 0V.
On pin 14 side is 5MOhm and growing, on other side (jumper) is 138 KOhm
On pin 8 side is 22.26 KOhm, on other side (jumper) is 123 KOhm
Try to remove PC97, PC99, PC98, PC102 and check again?

PC100 and PC101 measure on board have 1.51 nF. It's not too low?

terabajt ha scritto:Try to remove PC97, PC99, PC98, PC102 and check again?

Try to remove the capacitors PC97, PC98, PC100, PC101 and try again without them.

terabajt ha scritto:PC100 and PC101 measure on board have 1.51 nF. It's not too low?

It seems ok.

After remove the capacitors PC97, PC98, PC100, PC101 on pin 8, 14 of PU5 is still 0V.
After remove PU5 (without PU5 on the MB):
PIN1:19.84KOhm
PIN3:0.42MOhm
PIN4:19.83KOhm
PIN5:46KOhm
PIN6:19.81KOhm
PIN8:OL
PIN10:OL
PIN11:GND
PIN12:OL
PIN13:OL
Why PU5 won't start?

Solder the chip PU5 back to the place and post a clear picture from both sides of the chip to inspect the solder joints.

Ok, I think I used too high a temperature. After solder fourth PU5 I have 2.5V on PIN8 and 5.19V. The fifth time I used a much lower temperature and now on PU5 i have 5.19V on PIN 8 and PIN 14.
Now, when i connect the power supply and push the power button, fan starts for 2 seconds and for 5 seconds:
PL 8004: 1V
PL 8000: 0V
PL 8002: 0V
The main board turns off and 3.3V 5V only tensions are present.
Try to replace PU8000 ISL95829AHRTZ-T ?

Measure the resistances to ground on all coils.

Measure the voltages to ground on all coils for a short time when the machine is turned on. You may have to turn on the machine multiple times to measure all of the voltages.

PL2: 8.51KOhm / 5.19V
PL3: 23KOhm / 3.3V
PL5: 4.5MOhm / 0.22V
PL12: 51Ohm / 1V
PL2001: 142Ohm / 1.20V
PL8000: 7.03Ohm / 0.0001V (use PEAK function: Pmax: 0.59V)
PL8002: 6.52Ohm / 0.0004V (use PEAK function: Pmax: 0.48V)
PL8004: 16.76Ohm / 1V

Measure the power consumption (in mA) of the board when the machine is turned off.
Measure the power consumption (in mA) of the board when the machine is turned on with and without RAM memory connected.