ASUS 5538G no power at all

[rippergr]

Hello all,
I have an asus 5538G laptop which doesnt power on.
I test the ac adaptor and the power jack , I have power to the connector of the power jack.
Can someone tell me how can I dig deeper?
I found the diagram which is here
https://www.badcaps.net/forum/attach...4&d=1385748314 Thanks to Francisco.s
I think I have to start from the power voard page 35 but I don't know how to start.
If someone can give me directions to start.
Thanks in advance.

[polytek]

Re: ASUS 5538G no power at all

i think its acer aspire 5538G not an asus, please upload schematic or motherboard model name, to help you;

[rippergr]

Re: ASUS 5538G no power at all

Yes you are right. it is ACER and not ASUS
I have the link of the schematics in my first post.
and here is another link to schematics.
http://adf.ly/6548800/https://mega.c...TBnfVaPT57HY8I

[polytek]

Re: ASUS 5538G no power at all

check the B++ of tps51125 see the picture attached;
and then check if pl4 have 3.3V and PL5 have 5V

[rippergr]

Re: ASUS 5538G no power at all

I measure it with power only (the laptop doesn't start anyway)
pin 16 of tps51125 no voltage.
pl4 no voltage
pl5 no voltage

Do I have to press the power button or just to connect the power adaptor?

[polytek]

Re: ASUS 5538G no power at all

just when you plug the power adaptor you should mesure this voltage.

[polytek]

Re: ASUS 5538G no power at all

check between PQ7 and PQ8 you should find 19V if there is no voltage try to change PQ7 (4407)

[rippergr]

Re: ASUS 5538G no power at all

on PQ7 I have in all pins 19,30V
in PQ8 I have 19,30 V in pins 1,2,3,4 and 0V on 5,6,7,8

[fddizon]

Re: ASUS 5538G no power at all

if all pins in PQ7 are 19v, PQ7 maybe shorted.
check without battery and ac adapter, with ohm meter if source and drain is short.
replace if shorted.

if PQ7 gate voltage is high, 5 6 7 8 pins should have 0 volts

[rippergr]

Re: ASUS 5538G no power at all

if all pins in PQ7 are 19v, PQ7 maybe shorted.
check without battery and ac adapter, with ohm meter if source and drain is short.
replace if shorted.

if PQ7 gate voltage is high, 5 6 7 8 pins should have 0 volts

I think you are right. I measure PQ7 with multimeter in diode mode and pin 1,2,3 (which according to datasheet http://aosmd.com/pdfs/datasheet/ao4407.pdf are source)
and pin 5,6,7,8 (which are ground) all measure .000 both ways(I. is infinitive in my multimeter)
in PQ8 it measure only in one way .
So I suppose I must first change PQ7.

[atsio]

Re: ASUS 5538G no power at all

Remove it and check it of the circuit.

[rippergr]

Re: ASUS 5538G no power at all

Hmmmmm I think I broke it :p

I am waiting for a new one.

[Agent24]

Re: ASUS 5538G no power at all

If it broke in half that easily it was probably blown anyway

[rippergr]

Re: ASUS 5538G no power at all

I change the mosfet with a new one but still no the laptop doesnt power on. Any idea?

[fddizon]

Re: ASUS 5538G no power at all

ripper,

you should check voltage signal again bro.

drain, source and gate voltage...

[Agent24]

Re: ASUS 5538G no power at all

Yeah, could be the gate drive circuitry also failed

[rippergr]

Re: ASUS 5538G no power at all

Ok the problem now was that the ac jack was a little out.
It's ok now. Everything working fine.
It was the mosfet PQ7 that was blown away.
Thanks everyone for your help.