Asus UX305CA minor water spill, no display or external

[flasheverything]

Got an asus ux305ca for basically parts price. I've already salvaged the m.2 ssd off of it (working fine), so the rest is basically for testing. Just wondering what diagnostic procedures I should go through to narrow down the problem or call the motherboard gone. Now the battery is still good (I assume) it still reads good voltage but I can't test if the laptop is drawing any voltage. When I plugin the battery and press the power button, the power led turns green and I assume that means atleast the motherboard isn't shorted. I also found out the ALC3236 realtek audio driver is the only smc instantaneously getting hot when initially turned on. I don't have any schematics and I tried finding the schematic for that realtek audio smc but I only found a slight variation. I have the necessary tools and I should be able to diagnose even maybe replace some components. I just want to know if this motherboard is even recoverable. I will attach a link to the motherboard. The circled area shows where the location of the water spill from the keyboard side and seeped into the display connector. I only saw a tiny bit of corrosion on the display connector and only about 3 pins looked darker from the far right. The square bit is the audio smc which gets hot when turned on. I haven't tested anything else since, looking for any help or experience with this. Underneath the motherboard is a black cover between the motherboard and the keyboard. The spill looks like it was right on the power side of the board.

edit* now I don't have the right charger for this and I haven't tested it from a charger adapter. I don't know if that'll make some difference. I have only tested from the battery

https://imgur.com/a/GET4O#nXPfNsp

After opening up and looking underneath the motherboard there was a small dried water puddle outline around the power side of the board.

[piernov]

Re: Asus UX305CA minor water spill, no display or external

First try disconnecting the speakers and see if the audio IC still gets hot. Then check resistance of the ceramic caps around the audio IC. If one of them shows very low resistance, it is likely that the audio IC itself is shorted, so remove it.

[flasheverything]

Re: Asus UX305CA minor water spill, no display or external

First try disconnecting the speakers and see if the audio IC still gets hot. Then check resistance of the ceramic caps around the audio IC. If one of them shows very low resistance, it is likely that the audio IC itself is shorted, so remove it.

I'll check asap. Also is there anyway I can bypass the audio ic without removing it? edit* I turned on with the battery plugged in and remove the speaker connector, still got hot. Should I check cap resistance with battery plugged in or removed?

[piernov]

Re: Asus UX305CA minor water spill, no display or external

Battery disconnected. If you conclude that the IC is internally shorted, you must remove it otherwise it will be causing issues (pulling power and data lines to ground).

[Th3_uN1Qu3]

Re: Asus UX305CA minor water spill, no display or external

Agree, audio IC should not be getting hot. If you remove that the machine will likely boot. Hot air time.

[flasheverything]

Re: Asus UX305CA minor water spill, no display or external

well I accidentally shorted one of the power coils (was trying to measure voltage output and it's no longer power on. I'm trying to figure out where the the short is happening and replace some components to get it to square one again. If someone can help me out, let me know. I accidentally measured voltage on the second power coil and some sparks happened but I quickly took off the power. I don't know how I managed to do that. I have enough experience to know not to do damage. I guess I got too close and put the multi meter leads on both sides of one of the coils. But I read the voltage on that same coil again and it was reading 11.X volts, which I assume is still good then. If you don't mind the questions, where am I looking for the power delivery from the battery? Or should I just jerry-rig a power adapter and maybe that bypasses the battery side of it? Can I trace down where the main board isn't getting power from?

[piernov]

Re: Asus UX305CA minor water spill, no display or external

Which coil got shorted? Was it shorted directly to ground or to another component?

[flasheverything]

Re: Asus UX305CA minor water spill, no display or external

Which coil got shorted? Was it shorted directly to ground or to another component?

I may have shorted it from tapping the closest mosfet. It's the 3R3602V62 coil right next to the battery connector. That's all I did for a split second, then there was a tiny spark, and no green led turning on. I would try diagnosing on my own, but this is getting annoying but every part I try to search online gives no results so I can't really search for datasheets.

[piernov]

Re: Asus UX305CA minor water spill, no display or external

First try disconnecting the battery for a few minutes if you didn't try already.

Repair guide attached, sadly that's the best you could find for this board…
Anyway, start by checking if you've got AC_BAT_SYS, which you probably don't.
If it's missing, check for a short to ground on that line.
If it's there, you could refer to the "AC POWER ON SEQUENCE" page to check which power/signal line is missing.

[flasheverything]

Re: Asus UX305CA minor water spill, no display or external

update* I plugged in the battery for couple of minutes and one ic started heating up, slowly. Again I can't find any datasheet for this, so I don't know what it is I should be replacing. I would also like to know why it is heating up.

http://imgur.com/a/LWjvC

it's the center ic and it says "2n=2m 93" I have no idea what that means and google shows nothing

[piernov]

Re: Asus UX305CA minor water spill, no display or external

Richtek RT8249C, datasheet attached.

Is it really hot, like too hot to touch?

Give voltage measurement on pin 12, 3, 13, 20, 6, 18, 8.

[flasheverything]

Re: Asus UX305CA minor water spill, no display or external

Richtek RT8249C, datasheet attached.

Is it really hot, like too hot to touch?

Give voltage measurement on pin 12, 3, 13, 20, 6, 18, 8.

when I measure pin 12 to ground, there's a tiny spark, Is it shorting somewhere?

[Tiagocamara]

Re: Asus UX305CA minor water spill, no display or external

Thru your multimeter maybe. Check if you dont have the red probe connected in amp socket

[piernov]

Re: Asus UX305CA minor water spill, no display or external

You shouldn't have any spark when measuring voltage with a multimeter (voltage is too low and multimeter's impedance too high for that). Make sure your multimeter is set right and is trustworthy.

[flasheverything]

Re: Asus UX305CA minor water spill, no display or external

nope, it's all good. Now the ics not heating up anymore, so I assume it's done. All I did was the positive lead on pin 12 and the other on motherboard ground. But it sparked for some reason. I don't think even the neighboring pins would cause a spark? Well it's not heating up anymore, so I gotta measure where I originally shorted this thing.

[diif]

Re: Asus UX305CA minor water spill, no display or external

nope, it's all good. Now the ics not heating up anymore, so I assume it's done. All I did was the positive lead on pin 12 and the other on motherboard ground. But it sparked for some reason. I don't think even the neighboring pins would cause a spark? Well it's not heating up anymore, so I gotta measure where I originally shorted this thing.

The spark would suggest your probe touched a neighbouring pin.

[flasheverything]

Re: Asus UX305CA minor water spill, no display or external

The spark would suggest your probe touched a neighbouring pin.

I even fixed some needles onto the probes and had my camera zoomed in on the chip. What are some ways I can check voltage in? I know I could trace back before the pin.