Acer Aspire 4820TG - No display, black screen

I own an Acer Aspire 4820TG with Windows 10 Home installed. The laptop worked just fine until yesterday.

It started freezing during normal desktop operation, i.e. web browser and spreadsheet opened. The only way to exit from the frozen state was a hard shutdown (holding power button down 10 seconds).

The laptop would boot with a working display two more times after being turned on again, but only after waiting >1 hour after the shutdown. However, on both occasions the display would freeze again after a couple of minutes while working in Windows 10.

Since then I observed the following:
- There seems to be no picture on the laptop screen itself or an external monitor via HDMI at all. However, there were occasions where the mouse cursor was visible for one to two seconds, a snow storm picture briefly showed (static black and white), or a sort of melting snow storm picture is displayed (edges slowly turn completely white).
- The Acer boot logo/screen does not display (except for the two occasion mentioned above)

In general, the laptop seems to boot. I can enter the bios with F2 as well, but I don't see anything on the screen (laptop display or external monitor). There seems to be a video signal from the HDMI port, but it drops (the external monitor switches between looking for HDMI signal and a black screen with a signal).

I tried the following already:
- Removed battery
- Drained power by holding power button for >20 seconds after removing battery and power cable
- Removed RAM modules and cycled them through available slots individually and in pairs (either module works in the bottom slot, having a RAM module in top slot only prevents laptop from starting)

As this laptop has switchable graphics, I wonder how it could be that both of them don't work/are damaged? Is this an overheating issue with the GPU?

On another thread I read that taking out the CMOS battery for some minutes might help. Before I embark on disassembling the laptop, I wanted to see whether anyone has any other ideas.

Thank you

Accepted answers

billsey

Yeah, as long as you know how to take it apart and put it together such that it still runs when you're done, just go the one extra step and replace the thermal compound with new. Clean the surfaces good while apart so none of the old is still in there and use the the little pea sized drop on each surface...

All comments

knartz

I disassembled the laptop and removed the CMOS/RTC battery from the mainboard. Waited about 10-15 minutes and then put it back, assembled the laptop and turned it on.

Unfortunately, the issue persists. After waiting for the laptop to boot, and logging in blindly, I managed to make the mouse cursor appear by moving the mouse or moving my finger across the trackpad. It just shows on the external monitor, and does not remain for more than a couple of seconds.

Image: https://us.v-cdn.net/6029997/uploads/editor/vl/nw1co2quj6zt.jpg

knartz

UPDATE: I left the laptop outside on the balcony for several hours at 12°C to 14°C, then switched it on, and the display worked again. The Acer and Windows boot screens would show, and I was able to log into Windows as well. However, after 2-3 minutes the screen would freeze again, leaving a hard shutdown as the only option.

Is the problem overheating of the GPU or CPU? I thought in that case the laptop would just turn off, or restart rather than freeze the display.

HULU

Could it be that too much disk cache garbage caused the computer to overload?

knartz

So I turned the laptop on again after leaving it in the cold for another couple of hours. As previously, it would display the boot screen. This time I entered the bios straightaway and updated the Graphic Mode setting under Main to Switchable (from Discrete). Since then, the laptop works fine again. No idea if the change had anything to do with it, and why the discrete setting wouldn't work. The laptop was connected to the power adapter all the time, so discrete graphics mode should have been used anyway.

billsey

It sounds as if you've done a decent job diagnosing it. Likely the thermal module is not making good enough contact. You could replace the thermal grease to see if that helps. Also double check the fan is running...

knartz

HULU said:

Could it be that too much disk cache garbage caused the computer to overload?

Thanks for your answer. However, I don't believe that was the reason. I use CCleaner on a regular basis to get rid of temp files etc.

billsey said:

It sounds as if you've done a decent job diagnosing it. Likely the thermal module is not making good enough contact. You could replace the thermal grease to see if that helps. Also double check the fan is running...

That might indeed be the case. I have a suspicion that the graphics card used at the moment is the integrated Intel GPU rather than the discrete ATI/AMD Radeon GPU. There is no sure way to tell as Windows 10 does not have the "Switchable graphics" context menu item. The fan is running fine. I gave it a bit of a clean with the vacuum as well when I had disassembled the laptop.

billsey

Yeah, as long as you know how to take it apart and put it together such that it still runs when you're done, just go the one extra step and replace the thermal compound with new. Clean the surfaces good while apart so none of the old is still in there and use the the little pea sized drop on each surface...

knartz

I finally got around to replacing the thermal compound on the ATI GPU and the CPU. The laptop works again with discrete graphics mode enabled, so it must have been the ATI GPU that was overheating. The thermal paste on the GPU was almost like dried bubble gum and peeled off easily. On the contrary, the CPU thermal paste was very dry and I had to use some white spirit to dissolve it and remove it with cotton buds.

In summary, if you have a similar issue, it's most likely due to overheating which can be fixed by applying new thermal compound and cleaning the fan.

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