If using DOS, try arcmon.sys
It's a tiny little prog that you put in your config.sys startup file.
Just: "DEVICE=arcmon.sys"
You might drop lucky with the onboard card and it runs from it. Test it out on a spare PC monitor first, if the screen goes garbled then it's most likely worked. Immediately switch off the PC though then to save any problems. Also, make sure you can get back out of the monitor refresh rate if it DOES work !
One way is to create a batch file, so if you press a key it runs arcmon.sys, if not, things are normal. Doing that can then allow you to tweak your system. When it's finished yuo can just delete the batch file and have it always boot to monitor frequency.
arcmon.sys is available here:
http://www.mameworld.net/pc2jamma/downutil.htmlI've used it with great success on a number of cabs and PC systems
