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LCD Monitor Interference - Is there any hope?

by powermanaf / December 9, 2008 8:15 AM PST

First off I would like to say thank you to anyone who has taken the time to read this. This is my first post, and I am hoping someone here can help me out with this problem.

I recently purchased an ACER X213w LCD monitor to hook up to my laptop, an ACER Extensa 4420. I am having problems with horizontal lines running across my screen and I have figured out that it is an issue with my laptops power cable being too close to the VGA out port. The lines go away when I unplug the power cable, so this is how I came to that conclusion, and with a little reading on the internet. I have another external monitor that I hooked up just to see if it would do the same thing, but it didn't have the lines. This monitor though has the VGA cable coming right out of the monitor, as opposed to my ACER monitor that just has a VGA cable with two male ends that you can remove.

I am thinking it has to do with the cable. I have tried two different VGA cables, and neither of them have worked so far. I was wondering if someone could suggest a good quality cable that you know will block this interference. Or could the reason it isn't happening on my other monitor be the fact that the VGA cable comes straight out of the monitor?

I am stumped on how to fix this if it's not the cable, so any suggestions would help. Please let me know if I haven't described this well enough.



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do your cables have ferrite blocks?
by ramarc / December 10, 2008 4:11 AM PST
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Ferrite Cores
by powermanaf / December 10, 2008 5:51 AM PST

The two cables I have tried are advertised as having ferrite cores, but there is still interference. I might try the ones you have listed though.

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don't bother
by ramarc / December 10, 2008 6:13 AM PST
In reply to: Ferrite Cores

if you've already tried them, you'll get the same results.

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RF issue
by Willy / December 10, 2008 6:19 AM PST

It appears you have an "RF interference" issue. While ferrite cores limit this, the fact that the power cable is so close doesn't help the matter. If you can route the laptop power cable elsewhere, try it. As the other poster mentioned, adding "snap-on" ferrite cores to the cable could help but if the problem persists, you need to shield the power cable in some way. Better made cables have "metal foil" within them to reduce such issues. If you have access to yet another laptop power cord/supply, try it. Generic laptop power supplies can be had, if you really want to go that route. If the video cable itself can be replaced, try that as well. You can try copper or alum. metal tape, to wrap around the problem cable and check results as a last resort.

tada -----Willy Happy

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Power Supply
by powermanaf / December 11, 2008 8:06 AM PST
In reply to: RF issue

So what kind of power supply should I be looking for? What specs should I be getting the same of my current power supply? (power specs) Should I just be looking for one that is advertised as shielded?

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by Willy / December 11, 2008 8:29 AM PST
In reply to: Power Supply

The specs of the laptop power supply usually are located on them. Check them and look at those sold at computer shops or electronics, etc., for those by Targus and HP and verify the connector is propular as well. There are new/used at laptop resellers as well -OR- surplus vendors like:

and others, google for surplus vendors. The specs will need to be a close match, voltage can vary but the amps must be on the money. You can also complain to the laptop maker of your problems as well, its worth a shot.

tada -----Willy Happy

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Any follow-up?
by bluemanchu / December 18, 2008 9:11 PM PST

Hello, I have been having a similar problem with my Gateway laptop(same as Acer) and asus lcd monitor. Came across this thread and was wondering how things worked out or if these suggestions fixed the problem? Thank you

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by powermanaf / December 18, 2008 10:59 PM PST
In reply to: Any follow-up?

I still have not found a good enough VGA cable, and I haven't looked for a different power supply yet. I'm betting the power supply would be a better choice, if I can find a shielded one.

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try a good power bar
by lamprey / January 22, 2010 2:03 AM PST
In reply to: Well,

sometime a dirty power supply and interference from other equipment can cause interference. keep you cable away from other equipments and us a good high end power bar.

also, you can try shielding the cable and switch to digital like DVI or HDMI cable. you might need to upgrade you graphic card to do so.

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LCD Monitor Interference
by chuckg44 / March 28, 2011 12:09 PM PDT

This sounds like a ground loop issue.

When you plug in the power cord to the lap top you the monitor and the laptop are bonded together at the plug and they are also connected at the monitor cable. Unfortunately it sounds like the bond connection are not all that great. When you unplug the laptop you are eliminating one of the bond connections. One bond connection point means no interference. 2 bond connection points create a ground loop.

Good cables will have a choke on the wire ( at one end ) that reduces this effect.

Try using a good wire with a choke or find a way to bond all the equipment together in order to get rid of the ground loop.


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Bad Caps in Power Brick
by idoubtthat / November 16, 2011 11:11 AM PST

It's been my experience to find bad capacitors in the power-brick, find a good generic replacement power brick. I find them on New-Egg and problem solved so far. You can also try different wall outlets that are not getting feed back from the power brick. I have opened suspicious power bricks after finding a good replacement and it is always a scary fire hazard that had been going on inside the power brick. It is incredible what gets past UL cert now days.

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