Please help me debug it : dead after resolution change

[geok1ng]

Z39 kit running on Seiki panel.

1080ti.

was at 4k120Hz mode with cyan light

tried to start no man sky, but screen went nuts showing only middle of screen with black bars on both sides. NVIDIA control panel no help. so i power cycled the monitor.

No pop sound, no smell sounds, but also no image. i tested for no backlight - used a light source inn the dark to look for ghost images. nothing. 

the led changes colour, and the PC recognizes resolution changes but nothing gives it an image again. 

removed all cables and put them back, still same behaviour. 

what is the next step?

[geok1ng]

just to add : when the screen went nuts showing black bars, it also started strobing in an almost seizure inducing way. 

[ZisWorks]

Is your firmware new enough to support test mode?  Try enabling test mode by holding power button down for 10s.

This is weird enough to troubleshoot over videocall, emailing directly with contact info.