Acer Aspire ES1-431 no Power LED

[noipi]

I have an Acer Aspire ES1-431 Laptop, actually the normal behavior is whenever we turn on the acer es1-431 it must have Power LED should remain turned on (Blue)after pressing the power botton. However, after I received the laptop, the Power LED does not turn on, but the laptop is working fine. So I opened the laptop, and trace the LED with the DAZ8ADMB6D0 code schematic.

The 3v are present when i turn on the unit, and the resistors are good, the LED light of both PWR/Battery parts are fine.

any idea why there is no PWR led(BLUE) even the battery led no light(amber LED)

[mon2]

Re: Acer Aspire ES1-431 no Power LED

hi. You are saying that the PWR dual color LED is not defective but the BLUE / AMBER does not light up ?

The signals are linked to the IT8987 (U8) and driven by its GPIO pins.

The # suffix on the signal names = ACTIVE LOW. So if the signal is 0v (as an example); the led should be ON.

Check the voltage @ R313, both sides of the resistor against ground.

meter in DC volts (5v or higher is ok); red meter probe @ R313 & black meter probe to ground. What is the voltage reading ?

Then repeat for R312.

If U8 is not pulling this line LOW, the LED will not enable. Not familiar with the ITE chip operation but you can try a fresh BIOS upgrade which may reflash the firmware inside this controller and then test again.

[noipi]

Re: Acer Aspire ES1-431 no Power LED

hi. You are saying that the PWR dual color LED is not defective but the BLUE / AMBER does not light up ?

The signals are linked to the IT8987 (U8) and driven by its GPIO pins.

The # suffix on the signal names = ACTIVE LOW. So if the signal is 0v (as an example); the led should be ON.

Check the voltage @ R313, both sides of the resistor against ground.

meter in DC volts (5v or higher is ok); red meter probe @ R313 & black meter probe to ground. What is the voltage reading ?

Then repeat for R312.

If U8 is not pulling this line LOW, the LED will not enable. Not familiar with the ITE chip operation but you can try a fresh BIOS upgrade which may reflash the firmware inside this controller and then test again.

Thank you for the very fast reply.
i measure the voltages of the resistors and the result is here in the picture that attached. i will next to flash the bios, while im preparing my tools for it. I just post the result of the voltages.
sorry for the pic, im just using a low resolution cellphone, and also for my english, i'm Asian.
thank you bro.

[mon2]

Re: Acer Aspire ES1-431 no Power LED

Remove all power. Place your meter into DIODE mode.

Place one meter probe directly onto pin #1 of the dual color led.

Place other meter probe directly onto pin #3 of the dual color led.

Can you see the LED light up? If not, reverse the meter probes.

Then repeat using pin #4 of the dual color led. This is only to confirm that both LEDs are ok.

[noipi]

Re: Acer Aspire ES1-431 no Power LED

hi Mon2, yes it lights up when i test it in diode mode, lights up red and blue when test it with the probe.
Its very interesting problem, but the owner now wants to use it, even though without blue ON led on it.
Sadly, Now i need to re-assemble the acer es1-431 and give it back to the owner, he will return it next week after school weekend. Then i will update again sir mon2 after i flashed the bios. Maybe it needs to be updated, but if not, there might be a problem somewhere, or the IT8987 (U8) malfunction?
Thank you for your time, hope next week will update again.

[mon2]

Re: Acer Aspire ES1-431 no Power LED

Yes, appears that U8 is not enabling the respective LEDs.

As a work around, you can hard wire the BLUE led circuit by:

a) carefully removing the resistor and rotating so that one leg is towards the LED; the other side of the resistor is floating on the PCB or just sitting on the green solder mask (acts like an insulator so it is safe to do)

b) then with a quick use of the soldering iron, attach a thin wire (wire wrap wire is good) onto the floating side of the resistor and then ground this new wire

You are basically hard wiring the BLUE led to be always ON when there is power to the board.