Acer Aspire 5742G - no power up

[DeniS182]

Hi,
I have problem with my notebook - won't start , only clicking sound is heard from motherboard. PL28 was shorted to ground - +3VALWP rail.
I lifted up one side of this coil (side marked as "2" in schematic), sound stopped, and also PJ6 jumper, but short persist. I mean RT8206BGQW is bad , pin 30 - VOUT2 is shorted to gnd.I think correctly?
Can someone help me with this?
Thanks!

[ridamouh159]

Re: Acer Aspire 5742G - no power up

give me the voltage in all pins of RT8206BGQW -write it in photo -above incuded

lader my english is bad

[DeniS182]

Re: Acer Aspire 5742G - no power up

Measured with lifted up one side of PL28 (side marked as "2" in schematic) , and also PJ6 jumper.
RT8206BGQW:
1 - 2V
2 - 2V
3 - 4.966V
4 - 10V
5 - 0V
6 - 19.38V
7 - 5.07V
8 - 0V
9 - 0V
10 - 0V
11 - 0V
12 - 1.968V
13 - 0V
14 - 4.561V
15 - 0V
16 - 0V
17 - 4.554V
18 - 0V
19 - 5V
20 - 0V
21 - GND
22 - 0V
23 - 0V
24 - 4.554V
25 - 0V
26 - 0V
27 - 2V
28 - 0V
29 - 0V
30 - 0V
31 - 1.327V
32 - 5.06V

[mielta]

Re: Acer Aspire 5742G - no power up

HI
Check PQ48 it can also have bin shorted.

[DeniS182]

Re: Acer Aspire 5742G - no power up

hi,
PQ48 is not shorted.

[ridamouh159]

Re: Acer Aspire 5742G - no power up

Try to change the RT8206B if you haven t any short-circuit in the around of him
and no short-circuit in the picture included here

but be sure that your replacement circuit is new or worked sure

[ridamouh159]

Re: Acer Aspire 5742G - no power up

good chance

[meritosari]

Re: Acer Aspire 5742G - no power up

Probably Solid or tantalum capacitor have shorted

[nasrojee]

Re: Acer Aspire 5742G - no power up

Check PQ48 it can also have bin shorted.

[DeniS182]

Re: Acer Aspire 5742G - no power up

I lifted up RT8206B and short circuit persist. There isn't shorted components near this IC. Do you have any idea please?

[DeniS182]

Re: Acer Aspire 5742G - no power up

.

[DeniS182]

Re: Acer Aspire 5742G - no power up

Hi all,
at the end I bought new motherboard (second hand). Model is the same - NEW70 LA-5891P. But I found one difference. Connector in which is power button connected is on other place. - JLED1 and JLED2. But I have also problem with this motherboard, wan't to post. Only fan is running, led brights, but screen is black. I tried another cpu Intel i3-370m, another RAM, but nothing changed. Have someone bios file for this board? Thanks for any answer.

[mcplslg123]

Re: Acer Aspire 5742G - no power up

Try

[mcplslg123]

Re: Acer Aspire 5742G - no power up

Hi all,
at the end I bought new motherboard (second hand). Model is the same - NEW70 LA-5891P. But I found one difference. Connector in which is power button connected is on other place. - JLED1 and JLED2. But I have also problem with this motherboard, wan't to post. Only fan is running, led brights, but screen is black. I tried another cpu Intel i3-370m, another RAM, but nothing changed. Have someone bios file for this board? Thanks for any answer.

Is the pch same?? Check whether its Hm55 or Hm65?? If its Hm65 , 1st gen intel wont run.

[caspian]

Re: Acer Aspire 5742G - no power up

both the boards have got the same revision number and the same production date. So it is not expected they have major differences on PCH and BIOS.
To make sure, check whether they have got the same PCH model.

[shuc]

Re: Acer Aspire 5742G - no power up

Hi all,
at the end I bought new motherboard (second hand). Model is the same - NEW70 LA-5891P. But I found one difference. Connector in which is power button connected is on other place. - JLED1 and JLED2. But I have also problem with this motherboard, wan't to post. Only fan is running, led brights, but screen is black. I tried another cpu Intel i3-370m, another RAM, but nothing changed. Have someone bios file for this board? Thanks for any answer.

Your new second hand motherboard come from Packard Bell laptop... I don't know the exact model (if I'm not wrong, it's EasyNote TM85)...

[DeniS182]

Re: Acer Aspire 5742G - no power up

Chipset is same - HM55, GPU also. I tried it on external monitor, it post's but look what was on LCD. Internal lcd was black.I mean this is GPU problem and I need to do reflow/reball.

[DeniS182]

Re: Acer Aspire 5742G - no power up

After reball notebook works fine. But after some time, notebook won't charge battery. When adapter is connected on bar is written Connected, charging and battery is still on 26%. I replaced charger IC ISL6251 from other motherboard, but problem persist and on pin DCIN is 0V.

[DeniS182]

Re: Acer Aspire 5742G - no power up

I tried other battery, adapter, checked mosfets, but nothing changed.

[DeniS182]

Re: Acer Aspire 5742G - no power up

isl6251:
Pin 7- 0.2V
PIN 19 - 19V
PIN 20 - 19V
On other pins is 0V