Asus X555LD Rev. 3.1 no power

[caspian]

Re: Asus X555LD Rev. 3.1 no power

now check whether any pad located under PU9100 is shorted or not.

[Conste]

Re: Asus X555LD Rev. 3.1 no power

How do you mean?
If the solder points are directly shorted? This is not the case.

[caspian]

Re: Asus X555LD Rev. 3.1 no power

If there is no shorted pad, then it is ok to solder the new IC.

[Conste]

Re: Asus X555LD Rev. 3.1 no power

Hello,
Managed to buy a defective board from eBay. Board is okay, but no video on internal screen, but on HDMI. With this board I can test all the voltages and maybe find the fault of my board.
Regards,
Constantin

[Conste]

Re: Asus X555LD Rev. 3.1 no power

The defective board arrived yesterday and works expect of the internal screen. I measured some voltages and found out, that the screen isn't recognized by the board at all...webcam works btw.

I also found out, that Panel VCC of J4502 is not available

+3VS is there and also AC BAT SYS

What shall I do to revive the board?

[caspian]

Re: Asus X555LD Rev. 3.1 no power

first measure voltage on both sides of R4512.

[Conste]

Re: Asus X555LD Rev. 3.1 no power

Hello caspian,

Thanks for ur help in Advance!

Voltage on both sides is 0v, but the board is Rev. 2.0 and not 3.1 - when I look at the boardview of Rev. 3.1, there are two resistors in this area, on my board are only two of them.

Regards,
Constantin

[caspian]

Re: Asus X555LD Rev. 3.1 no power

If it is rev2, measure voltage on both sides of R4513.

[Conste]

Re: Asus X555LD Rev. 3.1 no power

Hello caspian, could you please send me the boardview of rev. 2, please?

[caspian]

Re: Asus X555LD Rev. 3.1 no power

here it is:

[Conste]

Re: Asus X555LD Rev. 3.1 no power

Hello caspian,
0v on both sides - does that mean that U4501 is bad?

Rrgards

[caspian]

Re: Asus X555LD Rev. 3.1 no power

U4501 is the main suspect now. but you cannot be sure unless you mention voltage on all pins of it. take a lot of care not to shorten it's pins when measuring. Es ist wirklich riskant zu messen.

[Conste]

Re: Asus X555LD Rev. 3.1 no power

Hello,

I tried to measure the Pins of U4501.

1 1,204V
2 1,164V
3 1,178V
4 3,268V
5 1,202V
6 0V
7 3,246V
8 3,261V
9 0V

10 0,04V
11 0,04V
12 0,04V
13 0,041V
14 0,04V
15 0,04V
16 3,26V
17 0,047V
18 0,048V

19 3,261V
20 0V
21 0,0047V
22 3,26V
23 3,24V
24 3,238V
25 1,202V
26 0V
27 0V

28 0,540V
29 0,540V
30 0,546V
31 0,548V
32 0,0014V
33 0,84V
34 0,84V
35 3,26V
36 1,206V

Thanks in Advance and have a nice evening!

[caspian]

Re: Asus X555LD Rev. 3.1 no power

If the laptop shows picture on the VGA and the HDMI ports, then U4501 is probably faulty. In another case, it is also possible that the CPU or GPU be faulty. Is there any GPU on the mainboard?
finding the datasheet of ANX1121 would help, but it seems it is not available. I found just a single page datasheet for it which is not useful to us.

[on/off]

Re: Asus X555LD Rev. 3.1 no power

ANX3111-ANX3112 pin out

[Conste]

Re: Asus X555LD Rev. 3.1 no power

If the laptop shows picture on the VGA and the HDMI ports, then U4501 is probably faulty. In another case, it is also possible that the CPU or GPU be faulty. Is there any GPU on the mainboard?
finding the datasheet of ANX1121 would help, but it seems it is not available. I found just a single page datasheet for it which is not useful to us.

Okay
GPU is an NVIDIA GeForce 820m

Maybe tomorrow I will manage to solder the N Channel mosfet to the other board, to make it power up again. Maybe then the laptop works again.

[Conste]

Re: Asus X555LD Rev. 3.1 no power

Hello,

I tried to solder the part, but I think I didn't suceed, no voltage after the part. Maybe the soldering is bad - can you tell me a good flux?

We also found out that on the board which powers up we has around 6v on PIN 12 of PU 9100. In the datasheet this pin is called SS1 (soft start 1). Does the IC get a voltage from here or does it produce this voltage by itself?

If the voltage Comes from outside, the Problem is another one.

Thanks in Advance!

[caspian]

Re: Asus X555LD Rev. 3.1 no power

pin SS1 does not come from outside.

[Conste]

Re: Asus X555LD Rev. 3.1 no power

Well, then the soldering job was shit. The solder didn‘t even melt, so I guess that is the problem.
Tomorrow I try to take the solderiron down and put new one on the pads.

I also ordered solderpaste, if this doesn‘t work.

Thanks again caspian

[caspian]

Re: Asus X555LD Rev. 3.1 no power

first practice soldering of a similar IC on a useless scrap board. then, when you learned the skills, try on the board which you are repairing.