An old source to cover most difficulties around connecting third party monitors to vintage Macs is the LAM page of Uwe Draeger:

edit: the page has been moved to: http://lam.kilu.de/

(was: http://www.fortunecity.de/wolkenkratzer/486/60/inhalt.htm)

It is written in German, not maintained any more and full of pop up advertisements, but with the descriptive illustrations most information will be understandable with few words.

Even a scheme for a DSub15-SCART-connector is given to use a TV set as a Mac monitor (lo res but impressive size).

(LAM stands for "Loeten Am Mac", it is a Mac specific guide relating to hardware hacks.)