HP x360 Black Screen

[lostsurfer]

I'm having the weirdest problem with an HP x360 I sometimes get a display on the laptop screen other times I dont. I've googled this problem a lot and have tried stripping the laptop, recovering the bios via windows key and B button on boot, I've flashed the latest bios, checked all the drivers etc etc etc.. It works fine via HDMI to another source but when the screen does work, it works great touch screen and all...i'm about to pull my hair out on this, anyone have similar issues with this model or this issue in general, any suggestion and insight would be much appreciated.

 

[SchizTech]

Just to be clear, it always works over HDMI? When the screen goes dark, look closely at it and try to determine if the image is still there, but unlit. Also, if you move the screen around (flex the hinge a bit or something) can that get the screen back on? These would point to a hardware issue, possibly the screen itself or the cable.

In Windows, you can check your power settings. If the screen goes off randomly, that sounds more like a hardware than a software issue but if it's predicable, there's a possibility that the laptop is turning the screen off and has a problem turning it back on for whatever reason.

How old is the laptop (might it still be under warranty)?

ETA: since you mention the touch screen: does that work when the screen is dark (over HDMI display)?

 

[lostsurfer]

Yea the image isn't there. I checked the hinges to make sure they weren't pinning down a connection and they're not. I've reseated the memory, the only thing i have done due to it having an internal battery is discharge the system with the battery removed.

 

[SchizTech]

Well then, at this point it's hard to pinpoint the culprit without taking apart the laptop and doing hands-on testing. At the shop where I work we'd try a different screen but the problem for you is that you wouldn't just have one sitting in stock like we do. It does sound to me like it's probably a hardware problem of some kind, if not the screen or cable than the motherboard. On that note, how hot does the laptop run? Can you tell if the insides are relatively clean?

 

[lostsurfer]

Yup it's litterally like brand new i checked and the warranty is good for 3 more months. all the connection are solid. the funny thing is that in the past i was able to get it to sometimes boot with the screen when doing a cntrl-f10 or f2. I almost want to say it's something with the freaking bios, but i've flashed the latest bios, i even have tried multiple bios recoveries to no avail...do you think that having not discharge the motherboard might have cause the bios to stay hung???sounds nuts but when i do the bios recovery i notice the caps locks light blinks fast 3 times then two short blinks..looked up the codes and it matches up the corrupted bios as the culprit.

 

[SchizTech]

Well a BIOS problem is a plausible scenario. If you're comfortable doing it, a hard reset of the BIOS (powering down, with no battery and the CMOS battery, if there is one, also removed) would be one step to try. However, doing opening the laptop to do that could also void the warranty, so if that procedure doesn't work, you could be stuck. HP might re-image the laptop on any warranty service, so keep in mind to back up any of your stuff if you do eventually ship it back under a warranty claim.

 

[SchizTech]

Leaving it unplugged until the primary battery drains would be a "safer" option, though it might not be enough if the unit does have a BIOS battery as most conventional laptops do.

 

[lostsurfer]

Well this one doesn't have a cmos battery which is kind of a bummer, and i've already taken the laptop apart to upgrade the hdd to a ssd and check to see if the memory was the culprit so the warranty might be void....i'll run a memory test tonight and disconnect the battery and hold down the power button for a minute then hook the battery back up and see if that does the trick, if not i'll try warranty road i guess..

 

[lostsurfer]

so update. I powered on the laptop to an external display, and as i touched the screen i could see the touches on my second monitor. So the touch screen is responsive, it must be the back light or power? which cable would i need to examine closer?

 

[SchizTech]

Actually the touch sensor (digitizer) is a second piece on top of the LED proper. If it's a problem with the LED backlight, you'd still see an image, just not lit (and you'd still have to replace the screen anyway). The cable in question is the LED cable between the board and LED panel. Typically you can diagnose a problem there if the screen flickers or changes when the cable is moved or flexed (sometimes just in moving the hinge forward or backward).