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VGA Lead question (maybe an easy question for the I.T members?)


Matt H

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Before I bought my new TV cabinet unit, my PC sat next to the TV screen and the VGA cable that the PC came with was long enough to the reach the RGB input on the back of the TV. Since I started using my TV as a monitor, I’ve been outputting the resolution in 1920x1080 and the TV has scaled it perfectly to fit the screen.

 

Now, I have to sit my PC a bit further away due to the shelving space that encapsulates the TV screen. Due to this, the VGA lead is too short to reach the RGB input in the back of the TV. No problem I thought and I purchased a VGA extension lead. The problem is, using the extension lead, the screen is now no longer scaled and I have that problem where you have to move the screen around with the mouse.

 

Plugging just the VGA cable in without the extension lead and it’s scaled perfectly again.

 

So why is it doing this? It’s obviously something to do with the extension lead. Is it a crap extension cable that I’ve bought?

 

Ta

 

Matt

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Thats very strange and shouldnt happen, Maybe take the lead back and get another one? Have you reset the resolution yourself?

 

I've tried all sorts, changing the resolutions back and fourth, turning the computer on and off, but only when I take the cable out of the equation does my TV scale it. V.odd.

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I've tried all sorts, changing the resolutions back and fourth, turning the computer on and off, but only when I take the cable out of the equation does my TV scale it. V.odd.

 

Ok without me being able to mess with it myself I would say it seems the vga cable is faulty. Ive never seen this problem before and ive used VGA extensions, So unless someone knows better I would suggest getting another one.

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I’ve been outputting the resolution in 1920x1080 and the TV

 

Where did you get 1080p from?

 

The term 1080p usually assumes a widescreen aspect ratio of 16:9, implying a horizontal resolution of 1920 pixels by 1080 vertical pixels.

 

Fair enough the P is progressive frames per second, but if you want to be pedantic

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How long is the extension? Resolution support decreases with length. Also, too much length produces DDC communication issues. DDC is a protocol used to transfer EDID information between the display and the graphics card/driver/OS. The EDID contains the resolution/timing information of your display. If that can't be communicated then standard VESA resolutions are used such as 640x480, 800x600, 1024x768 etc... I see that everyday in my work, it sounds very much like a cable length issue.

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Ok without me being able to mess with it myself I would say it seems the vga cable is faulty. Ive never seen this problem before and ive used VGA extensions, So unless someone knows better I would suggest getting another one.

 

Did your pc install automatic updates at the same the tried this extension cable?

 

No, no updates were installed.

 

Fair enough the P is progressive frames per second, but if you want to be pedantic

 

If I want to be pedantic? :rolleyes:

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How long is the extension? Resolution support decreases with length. Also, too much length produces DDC communication issues. DDC is a protocol used to transfer EDID information between the display and the graphics card/driver/OS. The EDID contains the resolution/timing information of your display. If that can't be communicated then standard VESA resolutions are used such as 640x480, 800x600, 1024x768 etc... I see that everyday in my work, it sounds very much like a cable length issue.

 

Ah, that would make sense. What would you suggest the maximum length would be? Is it a cable quality issue that determines that?

 

Is there anyway of getting around it? I.e some sort of booster perhaps?

 

 

Edit to add:

 

Would this cable length issue cause my TV to not scale the screen then?

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There is no absolute length for VGA cables. It depends on signal bandwidth (resolution and refresh rate), cable type, strength of signal (some video cards seem to put out stronger, cleaner signals), and acceptable quality loss. At 1920x1080@60hz you'll be lucky to go as far as 5m with a very good quality cable.

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There is no absolute length for VGA cables. It depends on signal bandwidth (resolution and refresh rate), cable type, strength of signal (some video cards seem to put out stronger, cleaner signals), and acceptable quality loss. At 1920x1080@60hz you'll be lucky to go as far as 5m with a very good quality cable.

 

Here's a pic of the cabinet just after I finished mounting the TV a few months ago. The PC sits to the right next to an sofa chair. I think the total cable length is ~2.5m plus the 1m cable? As you can see it's no more than 4m as the cable is pretty much extended.

 

(if anyone's wondering I've since re-located the rad)

 

When you notice the scaling, you can open display properties and check if you're outputting 1920x1080 or lower.

 

You mean when I'm just using the original VGA cable on its own? I can can confirm that the properties say 1980x1080. This is also true when I'm using the extension cable. it's just the desktop seems to be streched beyond the borders of the TV screen.

 

image

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Some extensions are not fully wired either, especially cheapo ones. Doubt you want to spend this much but one of the best VGA cables i have ever used (used to do installs in recording studios etc) was a VanDamme (not Jean Claude) Google VDC cables and you'll find them.

 

There's no way I'm paying £70 for lead! That ain't sparta, that's madness!

 

Perhaps I need to try a different lead. Could you recommend a fully wired one for as cheap as the birdy? That VDC cable would probably fetch more than my PC! :D

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I did use some bought from the dreadded CPC, these were 3m if i recall, and did work ok, but a few of them did have massive signal quality issues.

 

Not too sure if they make them any more, but Monster did some ok ones, again a bit pricey. failing that, maybe upgrade the video card to HDMI and buy a cable to go with.

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I did use some bought from the dreadded CPC, these were 3m if i recall, and did work ok, but a few of them did have massive signal quality issues.

 

Not too sure if they make them any more, but Monster did some ok ones, again a bit pricey. failing that, maybe upgrade the video card to HDMI and buy a cable to go with.

 

Upgrading is a no go. The computer's quite old and I'm looking at getting a Laptop in Feb so this is a temp fix for me.

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Fair enough, might be a possibility, CPC do a range of "install cables" and associated kits/blanking plates. Mainly aimed at the school/unit lecture theatre application but it would allow you to discreetly run a good quality long cable and have a firm plate to attach the origianl one to. Just a thought.

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Fair enough, might be a possibility, CPC do a range of "install cables" and associated kits/blanking plates. Mainly aimed at the school/unit lecture theatre application but it would allow you to discreetly run a good quality long cable and have a firm plate to attach the origianl one to. Just a thought.

 

What about this one?

 

http://cpc.farnell.com/pro-signal/psg03037/vga-audio-lead-3m/dp/AV18419

 

Or

 

http://cpc.farnell.com/_/41934/lead-vga-black-3m/dp/AV07372

 

Or

 

http://cpc.farnell.com/clever-little-box/lowprofile3-0m/vga-lead-m-m-low-profile-3m/dp/AV16355

 

?

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