How to trick notebook into thinking internal panel is connected?

[joshAU]

Hi all.
I have an asus F505DV that has a smashed screen, broken hinges, bezel and top cover.
The customer cannot afford to repair it, so they wanted me to remove the top of the unit and will just use the base as a desktop and plug into a monitor via HDMI.

However, for some reason, with this model, it REFUSES to display on the external monitor unless there is also an internal LCD.
If there is a internal screen, then the external displays fine.

This is running the latest BIOS.

I have set the display properties in windows 10 using Function-F9 to either external only, internal only, duplicated - and it makes no difference - no signal to external monitor.

I have completely removed the internal screen, cable, WLAN antennas and webcam... it it just the base unit.

Is there any way to trick this unit to think that there is an internal monitor?

There is no options in the BIOS.

Reading some posts on another Asus notebook, the poster was able to get to external monitor only, by first disabling secure boot and enabling legacy (CSM).
This model, however, doesn't support CSM.

However, I tried disabling secure boot then doing the Function-F9 on startup to see if I could get into the BIOS, but still no luck.

I even tried de-soldering the PCB from a LCD panel and connecting that via the LVDS cable, without success.
I suspect it may depend on the EDID (Extended Display Identification Data) data that is returned, and therefore would not be easily reproduced?

This is an internal 120hz FHD screen with a 40 pin LVDS connector.

Any suggestions greatly appreciated.

[mon2]

Re: How to trick notebook into thinking internal panel is connected?

If indeed you require an EDID, there appear to be tools (Aliexpress and others) that will allow you to extract out the EDID contents which can then be used to clone onto another.

Perhaps something like this:

https://www.aliexpress.com/item/3295...d=Fu0XqAKyErrF

Be sure to ask the vendor if this cable will work for your exact case.

Summary -> read out the EDID from the original LCD panel -> clone onto the 24C02 (guessing it is the same density for your LCD) -> solder this programmed eeprom onto this cable for testing.

Then the logic board will hunt for this I2C eeprom and its contents to fool the logic. Just an idea but worth a try if you are stuck. Do update this thread for future readers. Cool trick if it works (it should).

[joshAU]

Re: How to trick notebook into thinking internal panel is connected?

Hi mon2, and thanks for your reply, advice and suggestion.
Unfortunately the customer decided to not proceed with this, so I cannot say whether your suggestion worked or not.
I suspect it may, interesting cable.
Thanks for the suggestion.
I do already use a CH341A, so this cable may be worth adding to my adapters.
Once again, thank you.