Hi there - was wondering if someone could offer some advice to a noob...

I recently acquired an emac with a burnt tube. I have an LG Flatron monitor and the cable to hook it up to the computer, but when I turn it on I get a message that says:

Out of Range
71.9kHz / 89Hz

Can anyone tell me how to fix this without being able to see anything? Any advice would be greatly appreciated. If it helps, I currently have the emac connected to my older imac - so I can see it as a drive.

Forgive my ignorance...