Power causing flickering on D-SUB

[jim]

On my work laptop, the HP 550 in my sig, I've had loads of problems with external screen flickering - I thought it was just a dodgy monitor, but I've got a brand new monitor here exhibiting exactly the same problems.

I've realised that it's linked to having the charger on - if the laptop is plugged in, the screen starts to flicker. Unplug it, and go back to battery, and it looks perfect. The sockets are right next to each other, so I suspect that interference from the electrical current is affecting the signal in the monitor cable.

Is there anything I might be able to do to solve the problem? I thought about shielded cables, but I'm guessing that won't make much difference at the connector end where the problem is happening - I've tried rerouting the power cable but it doesn't make a difference.

Or alternatively I guess it might be an internal issue in which case there's nothing I can do. Any ideas?

[mrt9888]

If its electrical intereference then you might need a ferrite core on the power cable just after the plug and if the VGA cable doesn't have any then you could try one that has ferrite cores too.

[jim]

Got a ferrite core on the D-SUB, not the power cable though. I suspect that might be fairly expensive though, to muck around with the charger.

[Fraz]

Got a ferrite core on the D-SUB, not the power cable though. I suspect that might be fairly expensive though, to muck around with the charger.

Clip-on ferrites...

http://www.maplin.co.uk/Module.aspx?...32799&T=Module

[jim]

Clip-on ferrites...

http://www.maplin.co.uk/Module.aspx?...32799&T=Module

Didn't even know they existed! Shows how little I know about electronics I guess...

Thanks for that