Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
Hey Guys,
it's been a while since my last post and it seems we're running out further ideas. In the meantime I did these further things:
* Rework of the N2=-soldering using another new chip.
--> The measurements are the same as before.
* Read the [URL="https://www.richtek.com/assets/product_file/RT8249A=RT8249B=RT8249C/DS8249ABC-02.pdf"]manual of the N2=-Chip[/URL], hoping to get some new input...
There are several interesting spots:
First one...
chrisphl
Member
Last Activity: 01-05-2023, 12:44 AM
Joined: 08-11-2022
Location: S-H
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
36.2 kOhms
OL. I can see the value running higher and higher until some cap is fully charged and then the meter shows OL.
Which seems very logical to me. But -- and this is what I understand so far -- it does not fit the OL measurement which says "no load at all"... :-/
Yes, 0.0 Ohms when I shorten the probes. It's an auto ranging multimeter though.
Image is attached. The "2N=" is the same the following numbers...Leave a comment:
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
Hey Guys,
it's been a while since my last report. I got new N2-Chips (RT8249CGQW) recently. It took me quite a while until I figured out how to best redo the lift off solder pad on the VIN line so it connects to the chip properly. As I'm not a professional at the soldering hot air station (yet ;-)), I needed three attempts to get the chip soldered without shorten some other pins to ground. But finally I think I got it.
The Ohms measurements on LDO's didn't change (LDO3: ~36 kOhms, LDO5: OL) in...Leave a comment:
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
Hey everybody,
I got the messy chip out and got the Ohm readings to GND of the LDO's pads as well:
LDO5: OL
LDO3: 36,2 kOhms
My feeling is that LDO3 is OK ut LDO5 could be bad... what do you think?
I'm still waiting for the spare RT8249C chips though.
kind regards
ChristianLeave a comment:
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
In case it matters: At the moment (defective RT8249C is still installed) LDO3 shows 2.0 Ohms and LDO5 shows 2.4 Ohms.
kind regards
ChristianLeave a comment:
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
Thank you so much, I'll follow your suggestions. :-)Leave a comment:
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
I just ordered two at aliexpress and two more pcs an ebay which shall arrive between 6. and 8. Sept.
That's OK for me.
To speed things up, would it be OK to desolder the destroyed chip and inject 3V3 on LDO3 to determine some hardware that's getting hot which should be "short to GND"?
Kind regards
Christian...Last edited by chrisphl; 08-22-2022, 05:32 AM.Leave a comment:
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
Thanks for the advice! :-)
What do you think, is it a 3V3 short to GND for sure?...Leave a comment:
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
Thanks for the link. Very good price but ETA is 22. Oct... phew... I'll check my options... :-)Leave a comment:
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
I need to post further news on this case:
While looking and measuring around the board I found a chip that gets very hot for the first few seconds after connecting the power cord. I marked it on the attached photo. It has "2N=5F" written on it, must be a [URL="https://www.richtek.com/assets/product_file/RT8249A=RT8249B=RT8249C/DS8249ABC-02.pdf"]RT8249C[/URL] which is most probably the 3V3 source of the board.
Unfortunately I was not careful enough when measuring the pins and...Leave a comment:
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
Hi mon2,
thanks again for your reply!
...which I fully understand. :-)
...and means 3v3 line is not up and running, does it? :-)
That was easy so far...
...which I understand but that's the not so easy part for me: As one can see on the last image I posted, the connection from BQ to {SDA, SCL, ILIM} go straight to a via each. Unfortunately I cannot any tracks on the other side of the board so it is difficult to find the I2C-pull...Leave a comment:
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
Here we go: I wrote every measurement result into the BQ-chip overview image including their names to make it easier for you. Nevertheless please check that I named the pins correct.
I am very excited to see what we have to do next. :-)
kind regards
Christian
P.S.: I was able to determine D1 and D2 of schematic on page 36 in [URL="https://www.ti.com/lit/ds/symlink/bq24780s.pdf"]bq24780s.pdf[/URL]. So at least the upper left quarter can now be matched to the broken...Leave a comment:
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
Thank you for the educational link! Very helpful... :-)
Coil voltages are 0,0 mV for each but the one nearby the BQ-chip and the battery connector.
Update: After reviewing the datasheet of the BQ I think the 239 mV Coil must be (the only) L (3.3uH) in the schematic since I found the same voltage on SRP...Last edited by chrisphl; 08-17-2022, 07:13 AM.Leave a comment:
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
BATPRES show 0,0 V not matter if battery is connected or not :-/
(Q1: M3056M, the larger one; Q2 M3006M, the smaller one)
[CODE]
| Q1,M3056M | Q2,M3006M
Source and drain | 0,846 / 0,435 MOhm | 1,22 MOhms / 57 kOhms |
Source and gate | 1,55 / 0,504 MOhms | 1,55 / 0,504 MOhms |
Gate and drain | 1,18 MOhms | 1,77 / 0,435 MOhms |
[/CODE]
Note: If there are two/values it depends on changing the probes.
Why does...Leave a comment:
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
Hi again,
thanks you for your explanation. This helps me a lot to understand how the motherboard should work.
I did some measurement on the Mosfets Q1 & Q2 and also an the BQ-chip according to the schematic.
Drain and Source of both Mosfets are 19,54 V, Both Gates show up 24,22 V, which seem very OK from my point of view.
Find the attached image to get the readings on the BQ-chip.
My understanding is that it is working fine according to the switching of the Mosfets...Leave a comment:
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Re: Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
Hey mon2,
thanks for your fast reply!
I'll try to answer as detailed as possible:
Yes, the cats are absolutely fine.
I cannot locate the nearest Mosfets to the power connector in terms of shortest trace to the Mosfets. However I was able to take some interesting photos and I found the [URL="https://www.ti.com/lit/ds/symlink/bq24780s.pdf"]BQ...-chip[/URL].
I made copies of the overview images and marked the spots where I took the microscope shots....Last edited by chrisphl; 08-16-2022, 12:45 PM.Leave a comment:
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Dead Asus VivoBook S13 (Model: S330U); Help on repair wanted.
Hi folks,
I got a Asus VivoBook S13, Model: S330U. It is absolutely dead after the power cord was bit by cats...
I disassembles the device and did some measurements already. I attached two photos of its motherboard.
What I've done so far:
* I tried to check voltages but couldn't find any other than 19V and some <1mV at some Mosfet gates (The single pin at the side where there three further source source pins).
* I searched for all caps and checked if they *beep to ground* for more than a sec. on both sides. There are a lot of them... -
Re: New Members - please post your introductions here
Hello Folks,
nice to be onboard with you all! I just came across the forum while searching datasheets for several ICs of a nearly dead laptops motherboard. I'm an Embedded Software Developer with some knowledge of circuits.
Thought it could be cool to learn more about circuits and maybe give something back.
kind regards
ChristianLeave a comment:
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