Acer VN7-592G no power at all

[Lorenxo]

Dear friends, i have a problem with my acer VN7-592G equipped with mainboard Rayleigh SLS 14302-1M
the board non power on (no battery led, no signs of life)
The notebook power on correctly until last week. But now nothing.
I test the Power Supply with multimeter and is OK (19v releaved)
If i put the Power Supply to board i have no 19v in board, nothing never in dc pin!!! and the power supply itself go in a some protection state and give me no more output current until i disconnect from dc connector and from wall plug.
I search for hot component in board...but nothing.
Where i can start my investigation??
I attach also the electric schematic...so if someone have some tips...
Thanks in advance
Lorenzo

[mon2]

Re: Acer VN7-592G no power at all

Remove all power. Meter in resistance mode (2k scale or similar).

Check the resistance of the first mosfet @ PU4302.

Source (1-2-3) & drain (5-6-7-8)
Source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

Post the readings. If 'OL' = over limit, this is a good start. Increase the resistance scale on your meter and continue to test.

Any liquid damage ?

[Lorenxo]

Re: Acer VN7-592G no power at all

No, no liquid damage.
Thanks... I will try..

[Lorenxo]

Re: Acer VN7-592G no power at all

Remove all power. Meter in resistance mode (2k scale or similar).

Check the resistance of the first mosfet @ PU4302.

Source (1-2-3) & drain (5-6-7-8)
Source (1-2-3) & gate (4)
gate (4) & drain (5-6-7-8)

Post the readings. If 'OL' = over limit, this is a good start. Increase the resistance scale on your meter and continue to test.

Any liquid damage ?

I have two meters... in one i read 1 (OL) until i set MΩ
In other meter that have automatic resistance mode i read the following value (that are the same on the first meter when i set MΩ)

.712 MΩ (Source - drain)
199.7 kΩ (Source - Gate)
.516 MΩ (Gate - Drain)

[mcplslg123]

Re: Acer VN7-592G no power at all

Check resistance on CLR?? Seems like shorting on +19v

[Lorenxo]

Re: Acer VN7-592G no power at all

Check resistance on CLR?? Seems like shorting on +19v

Do you refer to PR4404 of the schematic or PR4415? or other component?

[Techtiger]

Re: Acer VN7-592G no power at all

Do you refer to PR4404 of the schematic or PR4415? or other component?

as mcplslg123 pointed out when adapter getting cut off it's main line +19V short to ground PR4404

[Lorenxo]

Re: Acer VN7-592G no power at all

as mcplslg123 pointed out when adapter getting cut off it's main line +19V short to ground PR4404

Thx. I will check this.

[Lorenxo]

Re: Acer VN7-592G no power at all

I desolded the pr4404 and check with meter and the meter give me between 0.00 to 0.01 and on the surface component i read R010.
Is the component ok?

[Lorenxo]

Re: Acer VN7-592G no power at all

May be a diode PD4301 problem? If it is in short condition, it can make syntoms that i decribed?

[mcplslg123]

Re: Acer VN7-592G no power at all

Measure resistance on both pads of PR4404(while being removed from board). One side should show healthy resistance and the other side should show low resistance. You need to inject not more then 1V on the shorted side of PR4404 and see what is getting hot. You can increase the amp but dont go beyond 1V.

[Lorenxo]

Re: Acer VN7-592G no power at all

It's ok if i start with 1V and 0,5 amp?
Before inject power I measured the two pads resistance with ground... From one pads to ground i read 4,4 ohm from other pads i read OL (open loop) in my meter...

[Lorenxo]

Re: Acer VN7-592G no power at all

I inject 1volt in pr4404 pad starting from 0.5 to 2.5 Amp but no components become hot....
I must increase the amp/voltage or i have make some error??

[mcplslg123]

Re: Acer VN7-592G no power at all

pump more amps. Your dc supply is 5 amp?? If yes, then pump 5A. Voltage not more then 1V. What is the consumption on dc supply With 1V,5A?? Let it remain injected for 10 mins and then check if anything is hot.

[Lorenxo]

Re: Acer VN7-592G no power at all

My dc supply can go until 10 Amp. When i put 2,5 Amp i read 0.304 on display of my bench dc supply...
Now as you tell me i try 5 Amp...

[Lorenxo]

Re: Acer VN7-592G no power at all

Measure resistance on both pads of PR4404(while being removed from board). One side should show healthy resistance and the other side should show low resistance. You need to inject not more then 1V on the shorted side of PR4404 and see what is getting hot. You can increase the amp but dont go beyond 1V.

One doubt... what is shorted side of Pr4404 in which i must inject 1v the one with 4.4 ohm or the other side where i read OL?

[mcplslg123]

Re: Acer VN7-592G no power at all

The pad which reads 4.4 Ohms is where you need to inject voltage. Since your dc supply can take 10A, You can slowly go up to even 10A and observe consumption. However, voltage should be not more then 1V.

[Lorenxo]

Re: Acer VN7-592G no power at all

Injected 1V 10Amp for 1 hour... nothing became hot... very, very strange...

[mcplslg123]

Re: Acer VN7-592G no power at all

Injected 1V 10Amp for 1 hour... nothing became hot... very, very strange...

What was the consumption with 1V,10A on dc supply?? Dont expect anything to be wildly hot. A particular part of the mb should be marginally hot and then you need to concentrate on that area. Since voltage is too low, nothing will hot up like wildfire. Did you removed the heatsink on SOC??

[Lorenxo]

Re: Acer VN7-592G no power at all

Yes i removed the processors heatsink.
I read 0.390 in consumption... (that remain almost the same at various Amp)
OK... I will try to identify if there is a slightly hot component...