Problem with Dell D1025TM (17" Trinitron) at lower refresh rates?

[Tarkus]

Just purchased a used Dell D1025TM 17" Trintron, and noticed a 1/2 inch horizontal "wave" at the very top of the screen if the refresh rate is set lower than 100Hz. At 120hz, the "wave" disappears, and at 70Hz the wave is most noticeable. I doubt this is normal, but I did want to ask before I start yelling at the selling party.

Thanks!

 

[wurmyhi]

I've seen this with a florescent lightbulb nearby. Any electrical devices near your screen?

 

[jiffylube1024]

Check for interference (is your computer too close to the monitor?), but it's probably a problem with the monitor. I've learned the hard way that buying refurbished monitors is not the smart long-term thing to do.