My new Dell U2415 cycles through all-screen, solid White/Red/Green/Blue/Black colors when turned on, both when connected or disconnected from a computer.

The monitor was bought from Amazon (ships and sold by) on Aug 9, 2016. The problem first appeared on Sep 21, then on Nov 18, and now on Nov 28, 2016.

The first time, leaving the monitor unplugged for a week solved the issue. The second time, I could get back to normal operation by triggering a built-in diagnostics (BID) by pressing the 1st and 4th buttons simultaneously; then by pressing the 4th button I could cycle through solid Wh/R/G/B/Bl colors (and control cycling, in contrast with automatic cycling). After exiting from the BID, the monitor was working again (a "no input present" screen was shown, I just needed to reconnect the computer). Strangely, the initial screen of the BID was not solid gray (as expected from the manual), but a noisy pattern.

This time, I repeated the same steps, but the monitor still cycles through solid colors on exit from the BID. The initial noisy pattern of the BID looks even noisier. These videos illustrate the three events:

Link to video

The last video illustrates the BID test.

I tried to connect the monitor to a desktop computer with integrated Intel HD 530 video from Intel i5-6600 CPU (and Gigabyte GA-Z171N motherboard) with Debian Linux, to a Toshiba Chromebook 2 (2015) with GalliumOS Linux, to a Mac Book Air (Late 2013) with MacOS X Sierra, all through the HDMI port and no other cables connected. The result was the same: it didn't matter whether the computer was connected/disconnected or on/off; the monitor would only cycle through colors when turned on.

The 20-digit alpha-numeric monitor serial number is CN-0CFV9N-74261-66A-078S-A03

Date of manufacturing: June 2016 (80-130), Made in China

Model: U2415b

What should I do? I would like this issue to be fixed; even if the monitor starts working again, it is not OK that is happening periodically.