1200 display color problem

[zombi]

One of my friends has a display problem in his 1200. I remember a smiliar problem and the solution mentioned in amiga.org.

I searched the thread. But couldn't find it.

The problem is a missing color. It display yellow instead of white and grey instead of light blue and light yellow. Do you have any idea?

[zombi]

I think in this case the problem, although i hope so, is not the cable. It is the Amiga that produce wrong colors. There should be a failed think inside.But i dont know what is it.  

[zombi]

AmigaMance wrote:
So, the missing color is the red one. Have you checked the R wire of your cable if it is uninterrupted, or if the respective pin in your Amiga/monitor port is broken?

Then, what can i do if there is no blue signal in video port?