ASUS G15 G513QM-HN064T liquid spill on RT8231A

[Chemox]

A while back I cleaned a laptop that had liquid spilled on it.

After a week or two of working just fine it started to 'not boot' properly.
Fans spin up to the maximum and keyboard backlight goes on but screen remains black. Power cycling resulted in a hit or miss. One time it would boot the next it wouldn't.

Few weeks later, it never boots and only gets stuck in this intermediate mode. I suspect the DRAM doesn't get powered.

With the help of reddit I figured out that the IC next to the spill is the RT8231A from Richtek.
https://www.richtek.com/Home/Product...RT8231ART8231B

If I am correct the spill 'shorted' the TON and the VID pin. How am I supposed to go from here? I attempted to measure the resistors that were beneath the spill. Only the right one returned a reading. I'm new to this so I have no idea how I can ensure that the IC is broken or that the pull-up resistor broke.

Ordering the IC is currently a bit of a hassle due to short supply and shipping. So before I get a replacement IC, I want to be sure that the IC is a bust and that it's not just one of the resistors or caps nearby that broke.

[mcplslg123]

Re: ASUS G15 G513QM-HN064T liquid spill on RT8231A

What is the resistance on TON & VID pin?? How you concluded that these two pins are shorted?? The VID pin is connected to 5V_S5 rail. Maybe your 5V_S5 rail is shorted.

I'll suggest the following:
01.Measure resistance on 3V coil & 5V coil(LDO pin if you can figure it out)
02.Measure resistance on VID/TON pin of Ram IC

The resistors around the IC seems fine in appearance.

PS: You can refer to dell 3567 Vegas_turis 15341-1 mb schematic of ram ic. Its listed on pg51. Boardview for this dell is also available-so will make it easy for you.

[Chemox]

Re: ASUS G15 G513QM-HN064T liquid spill on RT8231A

I meant that the liquid caused a short on those pins and possibly did some damage, as the liquid was certainly conductive.

Do I measure the coils and pins to ground?

[mcplslg123]

Re: ASUS G15 G513QM-HN064T liquid spill on RT8231A

Yes, measure resistance on those points to Ground in Ohms mode. Start with a scale of 200 ohms and if reading is OL then move on to higher scale.

[Chemox]

Re: ASUS G15 G513QM-HN064T liquid spill on RT8231A

Pin 9: TON pin: No readout (OL @ 2000k)
Pin 11: VID pin: 0-1 Ohm

How am I supposed to find the 3V and 5V coil? Can you show me on the schematics from the dell 3567 Vegas_turis 15341-1 mb? So that I have an idea what I'm supposed to look for.

[mcplslg123]

Re: ASUS G15 G513QM-HN064T liquid spill on RT8231A

Do you have boardview for this model?? If yes, then post it here. Its difficult to tell where the coil is. You can post clear photos of your mb which may help. Look for IC marked 1225 or 2N. If any of these ic is present on your board, then thats your 3/5V regulator.

Going by your readings i feel your ram ic may not be shorted -rather it may be 5V_S5 rail which is shorted.

If you have a hot air gun,flux and necessary skills, to remove the ram IC, then remove it and then measure the resistance on VDD pin pad.

[Chemox]

Re: ASUS G15 G513QM-HN064T liquid spill on RT8231A

Sadly I don't have a board view. I only have one from the GA502IU which has the RT8248A which according to the documentation seems near identical.

Resistance on the VDD pin is 880 Ohm.

I measured again at the TON pin (1) and the resistor (2) and at the opposing side of the resistor (3), which according to the above mentioned schematic is connected to ground through a capacitor, I have a fast increasing resistance until OL (so fast that it only gives a valid reading for a few seconds, which I missed the first time round). If I then switch to voltage sensing mode, I measure a few millivolts dropping to 0 very fast.

[mcplslg123]

Re: ASUS G15 G513QM-HN064T liquid spill on RT8231A

VDD pin resistance is too low-should be atlest a few Kohms. Remove the ram ic and check resistance on VDD pin again.