Extreme CRT flicker/wobble

[albertyay]

I use an LCD (Samsuing 910t) with no problems, but when I hook up a CRT (Samsung 997df) at a refresh rate greater than 60mHz, I get an extreme screen flicker or wobble. It's more of a wobble around 70-75, but then turns into a a flicker (or a very quick side-to-side shake) at higher response rates.

The problem occurs with both the onboard video and the Radeon 9200 video card. I've unhooked the case fan and the psu fan from the system and the problem is still there. I've also plugged the monitor into an extension cord connected to a different circuit from the computer, with no change.

Could the PSU (only 250W) cause something like this to occur? Anybody else have experience with this problem?

Thanks.


MOBO: ASUS A7N8V-LA
CPU: AMD Athlon 3200+ (Socket A)
Memory: 1G PC3200@2700
Video Card: ECS Radeon 9200
OS: XP Home

 

[Matthias99]

Ah, Shaky Monitor Syndrome (SMS). I used to fix this all the time when I worked tech support.

Invariably, the source was an electrical motor (such as a fan, air conditioner, fridge, etc.) either on the same circuit as, or physically very close to, the monitor or the VGA cable. Transformers (such as the power "bricks" that things like printers and scanners use) also screw with the video signal pretty badly.

It sounds like you already tried a different circuit -- try physically moving the monitor/computer to a different location and see if the problem persists. If it goes away in a different room, you have something nearby causing interference. It is also possible (although unlikely) that your monitor or VGA cable are defective. Usually when a monitor goes bad it's much more obvious, though.