I have an LC connected to a Gateway EV700 17in monitor. The issue is to get the adapter set to 600X480, and have H-Sync, V-Sync and Composite signals on - with what ever switches set that. Since I have that set on the LC, I can use it on another LC I just fixed (it needs a floppy drive, the one it has is not reading disks), the IIfx with its 24bit card, and on my Power5300ce through its Monitor Out-Jack.
All adapters are different, that I know. It is just getting the setting right until it turns on the monitor. That is if the monitor can accept Mac signals. If it VGA at its minimum, it should be able too. The hard part is to get it to work on other settings - then you need to play with the switches once again and hope you get it right.