Acer Aspire 5740G wont turn on, won’t power on, no display, black screen problems

Laptop Acer Aspire 5740G won’t turn on, won’t power on, there is no display, just a black screen. This is a general diagnostic and repair steps to fix those problems.
Troubleshooting laptop Acer Aspire 5740G won’t boot, won’t power on, no display just black screen
When you push on the Power Button the Power led lights ON or NOT, your Acer Aspire 5740G won’t start up, and there is no display just a black screen. Possible problem and the fixes steps:
Battery has no charge left + AC adapter failed; you press the power button on laptop Acer Aspire 5740G nothing happens, laptop won’t turns on and there is no display, the battery has no charge left, the motherboard doesn’t receive any power, laptop cannot turn on. You plug in the AC adapter but that doesn’t help, your laptop Acer Aspire 5740G still won’t power on, there is a chance you have failed AC adapter. In this case try with another charger or check AC adapter with a Multimeter. If it’s dead, replaced with a new one.


Power circuit in wrong state or Over volt protection trips; you press the power button but nothing happens, laptop Acer Aspire 5740G won’t turns on and there is no display just a black screen, your laptop has static electric charge made power circuit in wrong state. Unplug AC adapter, take out the battery and hold down power button for 30 seconds, the static charge will dissipate. Plug in the AC Adapter and turn on your laptop Acer Aspire 5740G. This should restore the system to normal operating mode.
Hardware failure; the laptop powers on, but there is no display just black screen with Power led lights ON or your laptop Acer Aspire 5740G stock on logo or restart. In this case, it’s possible one of the Hardware failed. You can try to disassemble the laptop to bare minimum and try to reseat the hardware one by one and power on the laptop every time you reseat a hardware, to know the failed one, replace the faulty hardware.
Screen faulty or bad video cable connection; laptop Acer Aspire 5740G turns on, but screen is black, with Power led lights ON. Test the laptop with an external monitor connected to the HDMI port, VGA port, press the appropriate key to switch to it. If the external monitor works fine and load the operation system, most likely you have a faulty screen or bad video cable connection. Check them and replace the faulty one.
BIOS failed; Laptop Acer Aspire 5740G won’t turn on at all, if the voltage 19V, 3.3V, 5V OK  and electronics components on the motherboard are good, there is chance you have failed BIOS. There is a signal test confirmation on EC/SIO pin name RSMRST# . This pin must available 3.3V(tolerance 10%) than Bios Confirmed OK. If the test failed reprogram or replace the BIOS chip.

Laptop Power System has problem: Laptop Acer Aspire 5740G won’t turn on at all, probably some electronics components or chipset on the motherboard failed;  Disassemble the laptop and take out the motherboard. Ceck No burnt marks visible on the mainboard. Check chepset temperature (CPU,  GPU, Power-Supply IC …). Check power jack. Check motherboard receives 19V. with a Multimeter measure voltages on coils, check for any components shorted to ground.  checked 3.3v/5v is up and running?
If you  have 3VALW And 5VALW at coil. 3VALW should go to sio and from there you should get 3v at power button. Check SIO for corrosion,shorting or any componenets which looks suspect. Check 3 & 5v SUS voltage.
Will need an electronic boardview or Schematic Diagram for Laptop Acer Aspire 5740G. The failed electronic component has to be replaced.
Note: (In the comments we will be updated electronics components failure).
Motherboard dead; The Acer Aspire 5740G motherboard has to be replaced.

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For other Acer Aspire 5740G problems check the comments or write a comment.

6 thoughts on “Acer Aspire 5740G wont turn on, won’t power on, no display, black screen problems

  1. Solved Problem

    Laptop Acer Aspire 5740g dead (no power – no lights) . Adapter is tested ok , motherboard is getting power 19V from power jack . I’ve found some mosfets getting 19V also and one with 3.3V but nothing else (nowhere 5V , or 1.1V) .Also , I can see 3.3V on the power button but nothing on LEDs.
    The Laptop recovery by flashing KBC BIOS (MX25L1005) using a programmer.
    Acer_Aspire_5740G_KBC_Dump.zip
    laptop wont turn on

    Reply
  2. servis

    Today I have fixed one with this same symptoms, eg dead, no 3.3V no 5V.
    Checked supply of the TPS51123 everything ok, but no S5 enable, ok move next to SIO.
    Supply is ok, but there is no RSMRST, next checked with scope U16 EC bios chip, no comunication, removed bios chip, reprogrammed it, checked with scope, it’s working, power button everything ok, problem solved

    Reply
  3. dachi

    Same case happened to me 2 weeks ago, I have managed to fix it reflashing the eprom near to KBC I can’t remember location code but it has smaller size than BIOS, and you can find its dump file at acer official support.
    Good luck.

    Reply
  4. Solved Problem

    Some laptops only have one BIOS which has data for both the chipset and EC/KBC. EC/KBC stands for Embedded Controller/Keyboard Controller. All boards have this, it is a microcontroller that deals with all the basic stuff like handling the keyboard (hence its name), all the buttons and switches (including power button), all the LED lights, controlling the fan speed and so on.
    Other boards have two separate SPI flash chips, a larger capacity one for the main BIOS which the chipset accesses and a smaller one for the EC/KBC. Physically they will be in the same footprint. Your board is like this. It would be better referred to as EC ROM, but for simplicity it is usually called EC BIOS. On your board U16 is EC BIOS. U56 is main BIOS.
    On the board the EC is the large square TQFP package, the one with a lot of pins on all four sides.
    To check the BIOS for activity using your oscilloscope, check pin 1 (Chip Select). It should always have a changing squarewave on it, which means it is constantly being accessed to do stuff. If the waveform moves for a few seconds and then stops, turning into steady DC, then the BIOS is bad and needs to be reflashed.

    Reply
  5. Solved Problem

    I have got the laptop fixed after replaced U72 and re-programmed BIOS (U16).
    I did change mosfet Q38 to fix my laptop!

    Reply

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