Computer Monitor Cuts Out When Switching Lamp

Hi, I have been having issues with my computer monitor and laptop recently where the monitor will cut lose signal or cut out and go to a fuzzy screen and I have to turn off and on, this happens quite randomly every hourish so isn't to bad and I can live with it I am just curious at what might cause it. Initially I thought it was a problem with the monitor or laptop, but now I have just realised that when I flick the switch of a lamp 3 or 4 times it causes the monitor to cut out. The lamp is plugged into the same ring main.

Can anybody think why this might be? Like I say its not a big problem but I'm quite interested in what might cause it.

Thanks

It's probably cause by spikes or electrical noise that's created when something somewhere else in the house is switching on and off. Easy option is try using one of those surge arrestor plugs for your computer and monitor.

They come as either a multisocket like this


Or as a piggyback type plug like this


or as a replacement plug like this

If you're not very handy with ascrewdriver opt for one of the first two. All three options should be available from your local B&Q, electrical wholesaler or computer shop.

Is it just the monitor? Does the same thing happen to the laptop when it is used on its own?

If it is the monitor, how old is it? It sounds like a capacitor is starting to go bad/has already blown (depending which capacitor) in the monitor. When you are switching the lamp, the capacitor is failing to cope with the changes in voltage. After a while the monitor may not work at all.

If it is both the laptop and monitor, how big is the area served by the ring main and what else is plugged in? It is possible that there is a voltage drop from too big a run of cable (or cable size is not big enough for area served).

There is another possibility that the ring is broken somewhere - now acting as two radials which are being overloaded. This is a more remote possibility and I would not think it is that unless you have checked everything else. An electrian can test the cables if it comes to that.

The most likely thing however, which I believe is causing your problem, is a faulty capacitor in the monitor.

So the issue relates to.
1 Computer Monitor
2 Laptop
3 Lamp being switched on and off affecting the above.
All plugged into the same ringmain.
Deffo get the ring checked for poor connections somewhere.
And if the earthing arrangements PME loose connections can cause all kind of weird symptoms.

I'd agree about suspect caps in monitor, however if it is connected to the laptop with HDMI, it might be worth trying a different HDMI cable. A failed contact in one or other plug (which is very common) can cause serious interference pickup, which could be throwing the monitor into chaos, although it should normally correct itself when the interference has stopped.

Hi thanks everyone for the replies. I have bought a new monitor today and so far is working better as it does not cut out, but every now and then there are still slight glitches. I think I will order a surge protected extension lead and hopefully that will fix it. Thanks again.

Would of been cheaper to try the sp extension lead first.

Whether it fixes your problem or not it's a good investment to put a surge protector on you PC and monitor. Let us know how it goes and good luck.