737 NG Display Test
 

Hello all!
I found the pic below and I would like to learn something more about it, please!

(Author unknown)

https://www.dropbox.com/s/l3k1lobyg7...01889.jpg?dl=0

Out of my training manual:
This is a DU (Display Unit) optical test.
You do these tests to examine the DU liquid crystal display (LCD). The DU BITE circuits do not monitor the LCD quality.
The failures to look for are line defects and element defects in the LCD.

Possible colors are red, blue, green,white and stripe.

It's a DU test you can access via the MAINT LSK on the CDU INIT/REF page. There is a sequence of pages you need to go through to access the test.

Wouldn't try it on an outstation if I were you though...:E

Thank you, gentlemen!
And what about the periodicity of this test, please?