Dock connected screen showing blank screen through DisplayPort

[PeterZhao]

Hi 

I have a HP EliteBook 840 G3 on a HP 2013 Ultraslim docking station. The docking station is connected to 2 displays. A Dell 1440p monitor, and a Dell 4K monitor, both through DisplayPort (DP to DP). However, I can only get the 1440P monitors working, the 4K one is detected, however shows a blank black screen. If I disconnect the 1440P monitor, then the 4K monitor starts working. I've switched cables around just to ensure that it's not the cable causing the problem. Is running a 4K display and a 1440P display not supported?

Is there a fix for this? 

Thanks in advance. 

Peter Z

[banhien]

@PeterZhao 

That is too much pixels for an Elitebook 840 G3 and an HP UltraSlim Docking Station 2013 dock. You can get one 4K monitor @30Hz and 1 FHD monitor @60Hz.

Please note: resolution does up, refresh rate will go down

Regards.

[PeterZhao]

I see in other user's post that the docking station can support one 4K monitor, just not two. I be satisfied if I can get a picture when I downscale the 4K monitor to 2560x1440. However, the 4K monitor still shows a blank screen even if i downscale. 

[PeterZhao]

If I downscale 4k monitor the resolution to 1440P, or FHD, I still get a black screen. Any idea what this is caused by?