Help, I have a blank screen on a Samsung ultrabook?

You could or could not get video on the external monitor at some point?

Most laptops have a toggle function key that switches video to/from external VGA port.

All-white on the laptop AND on the external display means the video adapter has failed (or the video circuitry on the motherboard if the laptop has no discreet video adapter).

If you can get video on external VGA, then most likely the laptop screen has failed. It's a possibility that an internal connector to the screen was not properly seated by whoever serviced it, and it came unseated. Some disassembly would be required to fix that, typically removing keyboard and plastics between keyboard and hinge.

To the Monitor from the NB's M???Board. The Flexible leads can crack and not pass any signal so they need to be checked with a Multimeter to make sure that there is no breakage. Though if it was returned like that I would seriously suggest that who ever changed the screen didn???t do a very good job.

As suggested above generally all NB's have a Key Combination to Toggle between the Onboard and external screens so you'll need to grab a copy of the Destruction Manual to find out which keys are involved if they are not marked on the keyboard.

Col

Yes the external monitor worked fine, toggle keys won't switch it back across though.

wires look to be fine but I'll check them with a multimeter, I haven't taken the screen off I've only accessed the connections from MB. are the cables fixed to the back of the screen by a connector or hard wired in?

If the external monitor works fine does this mean its not a driver issue?

Is it possible for the screen not to work even though there is current running to it and the back lights are lit up (it wouldn't glow white if they didn't work, would it?) ie; the LED or LCD's not to function somehow?

Thanks for you time and help

If the external monitor works fine does this mean its not a driver issue?

Yes the Driver and Video Generator are fine.

Is it possible for the screen not to work even though there is current running to it and the back lights are lit up

Most defiantly it can not work, Current only means power no signal. For example turn on a External Monitor but don't connect it to anything and it's working just not showing anything. Or the one that you currently have connected when it's on it has Current but no Signal hence no picture.

(it wouldn't glow white if they didn't work, would it?)

That's the strange bit generally when there is no signal or a scrambled signal the monitor remains black.

ie; the LED or LCD's not to function somehow?

While that is possible I thought that a new monitor had been fitted. I'm just not sure how you fit a new monitor to a NB without testing that it works but there are still many parts to a monitor and the Backlight and LED's are just a small part of what makes a Monitor. There is a Controller Board that turns the signal from the Video Card to a Picture that the LED's can display and this is generally fed by a Ribbon Connector Tracks on a bit of Cellulose that can have broken connectors.

are the cables fixed to the back of the screen by a connector or hard wired in?

Should be fixed at a connector but as I don't know which model you'll have to physically look. Though if the Ribbon Cable is hard wired in that means if it's broken you need another new monitor.

Col

Only sensible conclusion about damage is that it would adversely impact on the Video Card and most are not changeable in NB's.

That would also rule out it working properly with an external monitor though.

You could try clearing the BIOS and seeing if you can get the external monitor working again however.

Col

Now days they generally have a Super Capacitor to do that job. Or probably more correctly today they have returned to the Super Cap of Old to power the CMOS like the 286's had.

None the less there is normally a BIOS Clear Jumper which removes the power to the CMOS Chip though finding it without the Service Manual may be difficult if not impossible. Though here Jumper is probably a Misnomer today they have Pads which need to be Shorted hence the need for the Service Manual.

Col

I have been through all your ideas, and Thankyou all for the time you have given.

I stripped the entire NB down and tested everything possible, my conclusion is that either he has bought a broken screen or it was damaged when it was installed or stood on.
Everything worked fine except the screen itself not giving a picture, it could of been a damaged connector/cable on the ribbon cable, the power cables were working fine with correct current going through them, as was everything else.

So I gave him it back and told him to stand on the next one lol

Again Thankyou all for your time