Hi,
Thanks for your help!
The monitor was working, but the image was squished down on the bottom of the screen. I search for advices on many places, but I quickly found help here on Arcadecontrols.
Special thanks to Ken Layton who conviced me to go for a cap kit and telling me where to get it cheap (from Zanen Elect.).
I contact Zanen and they send me a complete cap kit and a vertical deflection chip (a small 21$, shipping incl. to Canada). They advice me to try the caps first and then change the vertical IC if it did not work. But since I had the chassis removed, I decided to do everything in one step. The bad side, I can't know what was the real trouble. The good side, it's now working better than ever!
Thanks again,
Yanick