Member Avatar for naldridge

It started happening about a week ago or so, I turned my monitor on and rippling lines were going up my screen quite small in width. The weird thing is as soon as I opened firefox and therefore my screen was predominately white the rippling stopped. But if there's a slight bit of purple on the screen as with the Daniweb page the screen ripples a bit but if I go to desktop which is mainly black, blue and other colours it starts rippling very intensely. I've tried degaussing to no avail and googleing the problem didn't really come up with anything too related, although its quite hard to describe in accurate search terms.

Any idea what might be causing this or is a new monitor going on my christmas wish list?


I guess its the whole different levels of colour effecting how much it does it that stumps me, I'll find a camera tomorrow and take pictures of the varying levels if that helps.

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The behavior described by — narrow ripples that shrink or vanish with very bright screens and get worse on dark/purple content — is the classic pattern of CRT “swimming,” i.e. a load‑dependent instability inside the monitor rather than a GPU/driver artifact. That the fault disappears with a different monitor (as noted after testing) strongly localizes the fault to the CRT unit itself; ’s swap test was the key diagnostic. ’s identification of “swimming” is on point, and the safety concern about opening a CRT is important.

Recommended non‑invasive checks (safe, in this order):

  • Swap the video cable and try a different input type/port if available (VGA↔DVI). A failing shielded cable can produce noise but usually not scene‑dependent swimming.
  • Change resolution and refresh rate to the monitor’s rated modes and observe whether the ripple tracks with refresh.
  • Remove/relocate nearby electronics (speakers, phones, chargers) and try a different mains outlet or unplug surge suppressors to rule out EMI/grounding.
  • Fully degauss using the monitor control, then power‑cycle and watch warm‑up behavior (note whether the effect changes after 10–20 minutes).
  • Capture a short video (30–60 fps) showing the same scene on dark and white backgrounds and note model/age — useful for shops or remote diagnosis.

If all above point to the monitor, the usual remedy is a technician inspection of the internal power/regulation stages (electrolytic capacitors and related components are common failure points). Opening or servicing a CRT is hazardous; discharge and HV work must be done only by qualified repairers. For low‑value consumer CRTs replacement is often more economical, whereas specialty or high‑quality units can be worth a professional “recap”/repair. Useful diagnostics to post here or give to a shop: monitor model, photos of the rear label, the short video described above, and whether the ripple is steady or varies with warm‑up.

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Member Avatar for barryt

make sure your graphics card are seated properly in the slot
it sounds like you got some sort of a spike on your graphics card , if you can try using another CRT monitor to rule out damage to you graphic card, if you are using onbord graphics try plugging in a graphics card to rule out damage to the on-bord system, if you ruled out the monitor and the graphic card the only other thing i can think of is that you have your cellphone charger or something like that near your screen
hope it helps

Member Avatar for naldridge

Cheers, we've got an old monitor in the spare room, i'll give it a try and let you know what happens

Member Avatar for naldridge

Okay, it appears to be a problem with my monitor as everything is working fine when using a different monitor.

Any idea what might be causing this to happen though and whether or not it might be fixable?

Member Avatar for Rik_

The problem is an effect called swimming. 99.9% of the time it is caused by a faulty capacitor in the monitor. If you feel you can do it, open your monitor up (DO NOT ATTEMPT THIS IF YOU HAVE AN OLD CRT MONITOR) and look for any capacitors that have domed up or leaked. If you find any, you will need to replace them with new ones!

Member Avatar for zash20

Did you tried changing the monitor refresh rate from the display properties option? Also try degauss, anyway.

Member Avatar for barryt

also try just bending your monitor cable just a wee bit to the left than the right oe so but Rik from RCE monitor solusion sounds plausable
:)
barryt

Member Avatar for Rik_

It being a CRT, I would recommend that you DO NOT open it up as there are certain areas that hold voltages that can easily KILL! It would be far far better to just replace the thing as CRT's and small flat panels don't cost a lot these days!

Edited by Rik_ because: n/a
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