ACER PREDATOR 17x not turning IC get very hot

[waakye]

Hi all,
I have here an Acer Predator 17x that does not turn on when plug in. When plug in the ic circled in red in image 17x1.jpg get very hot. Could someone please help me with which component that is? The marking on it is 3F=3H 51X.
Thank you.

I will also appreciate if someone has a boardview and schematic.

[mon2]

If there is an '=' in the part markings, it is from Richtek.

So, '3F=' equates to RT6575BGQW.

https://www.richtek.com/assets/produ...S6575AB-05.pdf

[waakye]

Thanks mon2. I will order the part.

[mcplslg123]

Perhaps wont help ordering a new IC. Very likely you have short on either 3V LDO or 5V LDO. Measure resistance to GND on both LDO pins.

[waakye]

Thanks, mcplslg123 and mon2 . The resistance on LDO3 pin3 of the ic to ground is 22.12k ohm and LDO5 pin13 to ground is 0.5 ohm

[mon2]

LDO5 pin13 to ground is 0.5 ohm

Too low for the LDO rail. Would you have an adjustable power supply? Dial it up to 1 volt (to be safe) and then inject onto the same LDO5 rail. Hunt for who heats up. Any part that is linked to this low current 5 volt rail is a suspect. It is also possible that this regulator is defective.

[waakye]

Thanks mon2. How many amps should I use?

[mon2]

As high as available on your power supply. With such a low resistance, the part will heat up quickly. Be sure that you are truly on the LDO5 pin and not a ground pin.

It is quite possible that PC325 may be the shorted capacitor raising this observation.

[waakye]

Thanks. After injecting 1V in LDO5, the component circled in green was lighting up in my thermal imager. I measured and 2 pins of the 3 pins measured 0.5 ohms. I think i found the short but without the schematic, I do not know what the component value is.
Thanks everyone.

[waakye]

would be nice if someone can upload the schematic or boardview.

[SMDFlea]

would be nice if someone can upload the schematic or boardview.

Post your request in the "Schematic requests ONLY!" sub forum and someone might just post them, they are available https://www.badcaps.net/forum/troubl...-requests-only

[waakye]

thanks, SMDFlea. I requested them

[mon2]

What are the topside markings of this SOT-23 component that is heating up?

If possible, take a clear topside pic of this component and post here for a review. We find that pouring some alcohol onto the top surface will enhance the markings under proper lighting.

Then suggest to flux and carefully remove this part. Do not lose the part. Then check if the LDO rail is back to a normal range for the resistance without this component. Do not power up but only confirm if the LDO5 rail is with a normal resistance.

[waakye]

The marking on the component is N1H0Z. with the component removed, still shows 0.5 ohms at pin13

[mon2]

Looks like the attached?

[waakye]

yes

[mon2]

Flux and remove this regulator. Test if the low resistance remains on the LDO5 rail.

[waakye]

Thanks to AL._.EX, I got the board view and it seems that I was looking at that IC U8100 wrong. below are the resistance values at all pins on U8100 that was boiling hot under thermal camera to ground.
Pin1> 60.9K
Pin2> 9.5k
Pin3>9.9k
Pin4> 4.2k
Pin5> 69.9K
Pin6> 90.5k
Pin7>99.9k
Pin8> 0.8M
Pin9> 0.9M
Pin10> OL
Pin11>0.8M
Pin12> 0.5M
Pin13> 0.5M
Pin14> OL
Pin15>0.8M
Pin16> 0.7M
Pin17> 0.8M
Pin18> 20K
Pin19>0.6M
Pin20> 9.7K

[waakye]

Based on the attached boardview and schematic, the ic that is getting very hot is U8100 which is TPS51225CRUKR

Link to schematic and boardview - https://www.badcaps.net/forum/troubl...-and-boardview

[mcplslg123]

Are you sure pin13 is 0.5Mohms(Mega ohms) or is it 0.5 Ohms?
If the readings are correct,then there is no short on U8100 and the IC itself may be bad.