FH5LI LA-J801P Rev:1.0 Motherboard problem in Acer Aspire 3 A315-56-54EL

[Darren Hibbert]

Hi. I'm a newbie so please go easy on me 😊

My Acer suddenly stopped working. When you turn it on, the power button lights up for 5 seconds then shuts down.

I opened it up and did the usual checks. 19v is coming in through the DC jack and the 19v is being distributed through the board where it should be. I originally thought that the BIOS was corrupted so I reflashed it with a CH341 programmer. This did not fix it, but then I measured for 3v from pin number 8 on the BIOS and found nothing!! Pin 8 should have permanent 3v. I then checked by schematics the other 3v points on the board and found nothing again. When I got to the Super IO chip (ENE KB9052QD) I was receiving the 3v from the associated pins.

Does this mean my IO chip is faulty or doing what it should?

Any further help would be appreciated 😉

[mon2]

Did you keep a backup of the original flash contents? If not, you will have to raise a request for a good bios image in the dedicated bios forum.

Reference the labels in the schematic - which bios chip are you measuring? Was the bios chip soldered back exactly the same as the original? Assuming the original bios was removed and reflashed and soldered back onto the board?

Often, the faults are with the power rails where a capacitor shorts and raises a higher than normal current draw so the local power rail will shut off and the party ends.

[Darren Hibbert]

Hi.

Yes I kept the original BIOS contents.

I never took the chip off the board and there is no 3v on pin 8.

The chip is XMC.

I have a thermal camera so could I use this to see if a cap has shorted?

[Sephir0th]

Playing with the BIOS firmware without removing the flash from the PCB is a risky task and often leads to permanent corruption, to start with.

On recent devices it is not common to have the +3VALW present at the BIOS chip anymore while the board is turned off. This requirement was decades ago and therefore this assumption will lead you in circles.

Additionally when you are looking for voltages then you have to do it during the highest consumption of the board, so inbetween these 5 seconds there the LED is on. I am convinced, the +3VALW will be present, otherwise there will be no way that the power LED works.

The question here is more whether the sequence stops at +VCCIN_AUX or whether it does even reach the late sequence, before the system shuts down.

You're asking for us being "easy" with you. However then you need to stop leading the repair attempt here, otherwise I see no way how you can make progress or even success here.

[mcplslg123]

I fully agree with @sephiroth's view.