Using laptop with external monitor only

[seskanda]

Hello

I have a Dell Vostro 3450 and the internal LCD screen has failed. I can hook it up via blue 15-pin VGA port to an external monitor, but I’m just able to go into the BIOS screen. When I try to boot up into Windows I get eight beeps followed by a black screen. Is any way to get it to work on external monitor without the internal LCD screen?

Thanks in advance

[veeg]

Hello

Yes.. https://www.amazon.com/s?k=usb+to+vg...l_6kng0y9s6b_e

[Rustys]

If the system is still under any type of warranty would file a claim. This could also be caused by the motherboard failure.
Could be a loose cable form the LCD to the motherboard.
Have you attempted the LCD test

To run the Built-In Self-Test perform the following:
[ul]
[li]Turn the computer off. [/li][li]Press and hold the D key while pressing the power button. This will start the BIST. [/li][li]The screen will display multiple flashing colors. Look for lines, distortion, or any other video issues you have observed. [/li][li]The laptop will restart when the test is finished.[/li][/ul]

If no video is shown yet at this point it is recommended to connect the computer to an external monitor (if available) to confirm if video problem is related to the LCD panel or to the computer’s video card itself.

It has also been suggested to clear the power and try removing the CMOS battery.

[seskanda]

Appreciate the help yet so far nothing works. I forgot to mention that I also tried using the HDMI port to my TV, but I had the same results as with the VGA port. Will have to wait until Monday and try the USB to VGA adapter. I got a USB to HDMI VGA adapter as well. It is similar to the one below:

https://www.amazon.com/Adapter-Support-Resolution-Windows-Desktop/dp/B0827W1W3R/ref=sr_1_1_sspa?keywords=usb+to+vga&qid=1577951102&sr=8-1-spons&psc=1&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEzMlo0MUpJNEtTM08wJmVuY3J5cHRlZElkPUEwNTMyMDA4MzY3WkROVFVNVzIwTSZlbmNyeXB0ZWRBZElkPUEwNTU0NzAwMzRDRjM5MFAxVzRZUSZ3aWRnZXROYW1lPXNwX2F0ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

I did the BIST but the screen is just blank, however as stated in original post it works fine when connected to external monitor via VGA port, but can only go into the BIOS after that I get eight beeps and black screen too.

[Rustys]

Then we will keep the thread open for a few days to see what the results are of the USB connection.

[seskanda]

I just got the usb adapter and that does not work at all. Cannot even get into the BIOS, pretty sure these things need an OS. I think since the flex cable for internal screen is disconnected that is what causes the eight beeps. Unfortunately, that cable is broken and do not have another to try, but that is last option for me. Unless someone else knows what else to do.

[Rustys]

Replace the flex cable which may not fix the issue.
It may be the LED screen that is the issue and or some other piece of hardware.

[phillpower2]

I think since the flex cable for internal screen is disconnected that is what causes the eight beeps. Unfortunately, that cable is broken and do not have another to try,

If you are getting eight beeps after having pressed the Fn and the F8 keys to toggle between displays then you are correct and the MBs video to screen ribbon needs to be replaced, the eight beeps is the Dell BIOS telling you that the power on self test has failed, replacement part here

[seskanda]

I really do not know what else the issue could be if not the flex cable or LCD screen itself

If you are getting eight beeps after having pressed the Fn and the F8 keys to toggle between displays then you are correct and the MBs video to screen ribbon needs to be replaced, the eight beeps is the Dell BIOS telling you that the power on self test has failed, replacement part here

I will find one of these LCD flex cables online and see if that fixes it.

[phillpower2]

Can you tell us how you initiated the LCD BIST as in what keys did you use and when did you press them.

The eight beep behaviour that you describe suggests that the video ribbon may have become detached from the motherboard but that would not affect you being able to run the Dell LCD BIST, if the test was initiated correctly it would suggest that there are two problems, bad screen and bad/disconnected video ribbon.

DELL VOSTRO 3450 DISASSEMBLY

[seskanda]

I did LCD BIST using the exact same instructions as mentioned in the above post, that is, holding the D key while turning laptop on.

I ran the LCD BIST on an external monitor not the internal one and the flex cable was disconnected as I threw it away since it does not work, also still waiting on that lcd flex cable to arrive, but if I plug that in and it works on external monitor without internal one I will be surprised, because it seems the BIOS does the eight beeps to prevent external monitor to work if the internal is not working.

[phillpower2]

Will address things one at a time but you need to be made aware of certain important information.

I ran the LCD BIST on an external monitor not the internal one and the flex cable was disconnected as I threw it away since it does not work,

You cannot run the LCD BIST on a non Dell monitor as the function is specific to Dell screens and not even all Dell screens have the function built in, the LCD BIST allows for the screen to self test and, if you run the LCD BIST on this Vostro 3450 notebook and you get nothing on the display the panel needs to be replaced.

It may have been nothing to do with the video cable but regardless of this if no cable connection is detected when the BIOS carries out the power on self test (POST) you will get these eight beeps as the lack of cable connection is detected as a fault by the BIOS.

The crux of it is, you cannot do anything without a fully functional video ribbon that is specific to your Dell Vostro 3450 notebook.

[seskanda]

You cannot run the LCD BIST on a non Dell monitor as the function is specific to Dell screens and not even all Dell screens have the function built in, the LCD BIST allows for the screen to self test and, if you run the LCD BIST on this Vostro 3450 notebook and you get nothing on the display the panel needs to be replaced.

It may have been nothing to do with the video cable but regardless of this if no cable connection is detected when the BIOS carries out the power on self test (POST) you will get these eight beeps as the lack of cable connection is detected as a fault by the BIOS.

The crux of it is, you cannot do anything without a fully functional video ribbon that is specific to your Dell Vostro 3450 notebook.

It turns out I mistakenly ran the BIST on another Dell laptop I have and not the Vostro 3450. I know the BIST only works on the internal screens of laptops. But, in my case, the BIST will not show anything at all. Of course, that can only mean it is dead. But the fact the external monitor works tells me the video card is fine and only internal screen is bad.

So if I simply connect a good, known, LCD flex cable and no screen at all then that should bypass the eight beeps, then? I hope that is the trick, still have to wait until Thursday to get it.

I hope all I need is this LCD flex cable and not an internal screen too just for the external monitor to work

[phillpower2]

It turns out I mistakenly ran the BIST on another Dell laptop I have and not the Vostro 3450.

Wow, how on earth did you manage to that :unsure:

But the fact the external monitor works tells me the video card is fine and only internal screen is bad.

I`m not convinced of this tbh and have my fingers crossed for you that it is just the missing video ribbon that is stopping you being able to use just an external display, the BIOS on OEM brand computers are notoriously picky and it is a toss up between Dell and HP who is the worst.

You need to connect the video ribbon to both the motherboard and the screen regardless of the fact that the screen does not work.

[seskanda]

Wow, how on earth did you manage to that :unsure:

It was a mistake Dell makes too many laptops that look alike

I`m not convinced of this tbh and have my fingers crossed for you that it is just the missing video ribbon that is stopping you being able to use just an external display, the BIOS on OEM brand computers are notoriously picky and it is a toss up between Dell and HP who is the worst.

You need to connect the video ribbon to both the motherboard and the screen regardless of the fact that the screen does not work.

I sure hope that is the case still have to wait until tomorrow to get the LCD cable. I think the BIOS wants an internal screen present even when external display is already connected and we try to trick it by only connecting the LCD flex cable. I prefer Dell BIOS over HP since HP rarely if ever boots from SD card reader but that is another topic.

Well that beats the whole purpose of this thread which is just using the LCD flex cable and external monitor.