Each adapter has its own settings for the switches, you need to either see if there are settings on the adapter itself (look on both sides), or figure out who made it and google. Mae sure that monitor does not have multiple input settings and you are connected to the wrong input by mistake.

Generally Sony trinitron monitors do all mac video modes, and quite a few came with Mac adapters in the packaging. So if by chance that adapter is the original for the monitor you might find the settings in the owners manual which you can download in PDF form on Sonys website.

Does the 9600 bong when you turn it on (if not there might not be a video problem at all)?