Atari ST & NEC MultiSync EA192M vertical lines

[DonQuichote]

Hi together,

 

i shot an NEC MultiSync EA192M at ebay for my Atari 1040STF. Works pretty good in hi and lo res using a selfmade ST2VGA cable with switch for both resolutions.

 

I used this wiring diagram from internet to build my cable and used good shielded VGA cable.

 

My only problem are vertical lines in the dark areas of the screen.

 

 

 

 

 

Seems not to be an shield problem. The unshielded wires at end of the cable solded at the switch i made so short as possible. Perhaps too high r/g/b level from Atari? Or somthing with the H and V sync signals?

 

Has anyone an idea?

 

 

 

(sorry for my english, i´m from Germany)