Hi, I was trying to connect my S330 to an external monitor. The monitor is an old one, monochromatic, Hercules tipe.
I'm having problems with it because I can't see very well. The screen moves horizontally and veritcaly and I can't fix this with the buttons on the back of the monitor.
Is it my monitor which is broken or the s300 interface is not "hercules" compatible?

I'd appreciate any help. Thanks!

These monitors are reported to work. you might be able to find them second hand if you are really lucky. The NEC 3D was a popular monitor, try that one first.
These monitors require special adapter cables from Redmond Cable (206) 882-2009 / (615) 478-5760.

Atari 1224
Atari 1435
Mitsubishi DiamondScan
Commodore 1080 & 1084
Darius TSM-1431
Taxan 610/420 Sony KV1311 Sony PVM
NEC 3D
Magnavox 8762
Zenith ZVM133Nyrup

It seems also that you can use a TV via the RCA output.
http://www.lilchips.com/roland/samplers/s330/