External monitor - interference non AC adapter related

Hello,

I have an NEC versa s940 laptop which I have recently tried to run through an external monitor for the first time. I have seen similar threads in the archives but where mine differs is that it is nothing to do with the AC adapter, I am getting the same symptoms irrespective of whether it is plugged in or not, these symptoms are.....

I have tried several different monitors and on all of them (to varying degrees) I am getting what can only be described as interference which can be seen as faint horizontal lines that appear to be scrolling up the screen. The guy at P.C world said it was a mis-match between the refresh rates between my laptop and the monitor which I am not convinced is the the case (Samsung tech support agree with me here) and I still think it is interference of some sort or maybe a fault with the graphics card or it's settings.

I have tried all the possible resolutions and refresh rates all of which had no impact on the problem (better or worse) I have also tried it at different locations to rule out something environmental. I rang NEC support today who was about as much use a a chocolate fire guard and simply said it was faulty but didn't sound like he really understood the problem.

Anybody seen this before? and is there any hope other than replacing the laptop?

Thanks

 

What cable are you using? Have you tried different cables? What are the quality of the cables?

 

Hello,

Sorry yes I should have added I have tried 3 different cables.

In P.C world the tech guy plugged it straight into a nother lap-top and the picture was crystal clear.

 

Are you sure that the outlet you are using has proper grounding? (Is the ground connector working properly ?)

 

Given that this problem happens even when the laptop is running completely off of the battery is this likely to be an issue?

I hope so as it would be an easy one (in theory) to solve.

Thanks

 

Slight update. I did some more testing and it turns out that the power adapter is having an impact but even when unplugged totally the problem is still there just not quite so bad.

Any ideas? Is this common to a lot of laptops?

 

I had the same problem with an HPw1907v LCD Panel connected to my Toshiba Laptop, after reading your article, I disconnected my powersupply and it has gone completly...... I am now in the throws of finding a solution to Toshibas dodgy power supply. and am at present using a universal one which has no such feedback.

Thanks again, hope this helps.

Toshiba site says a suppressor or double maganet on the connector to the laptop should sort it out ........ i will let you know in due time.

 

Sometimes this happens on my CRT's(more than one, different brands).
Happened on the external on my lappy, and my desky's monitor.
It like 50 x 1 pixel line going across (horizontal), scrolling.
But goes away after a few seconds.
Lucky me.

 

Whilst mine improved wuth the power adapter switched off it was still quite bad and as a photographer it just wasn't acceptable for critical work. It would seem that this was an issue with the graphics card and in the end turned into a show-stopper for me as my desktop recently expired.

In the end I have moved to the dark side (or maybe to the light side) and power-bought a macbook. Cracking piece of kit.

 

Unless you are running your monitor off a battery, then yes.