MSX problem!

[ave]

hey guys,

a couple of months ago I finally decided to buy an MSX computer because I want to play the exclusive Konami shooters on the original hardware! I succeeded getting a Sony MSX2+ F1XV in flawless condition and got it yesterday by seamail from Japan.
But here's the issue. I can't get the video signal straight, it keeps flickering or scrolling. When I connect it to my Philips CM8802 monitor (50/60Hz RGB), the picture is just "scrolling" really fast. I attached a picture of it:

http://img194.imageshack.us/img194/9373/msx1.jpg

I decided to try connecting the MSX with my rgb TV and it looks much better, but the picture still "scrolls" about once a second and certain areas are "wobbling".

http://img706.imageshack.us/img706/5545/msx2.jpg
http://img268.imageshack.us/img268/7558/msx3.jpg

I tried to capture that effect on the last picture with the blue screen and text. The text is wobbling back and forth and not just bent to the right as you can see on the picture.
My guess is that it is caused by the cable because the MSX itself boots and plays cartridges perfectly fine, but the video signal i.e. gets worse when I reconnect the cable: The image shifts when reconnected whilst the MSX is switched on, like the bottom of the picture is right in the middle.

My RGB-cable is an 8-pole DIN->Scart RGB, selfmade by a guy from the Netherlands. The people I've contacted to far don't have a clue, so you guys are basically my last hope.