Arcade monitor and pc gfx card settings

[lodoss118]

Hi i am having a problem in which when i plug my tri sync arcade monitor in and when windows starts or during the windows boot screen
my monitor gets out of range/sync. I have an ati 4850, if i connect to my pc monitor first then change it to 640x480 at 60hz and then
plug back my arcade monitor it works. After i restart though it still is out of sync its like window forgets the monitor settings?

[Gray_Area]

I think it's not detecting the arcade monitor, so it defaults to something higher than 640x480. Ask Sailor Sat if you might need an EDID dongle.

[Brenry]

have you tried booting with dual screen mode?  The multisync may be on the fritz defaulting at 1024x768 or higher mode, but you should be able to set the resolution on your lcd.