Connecting Laptop to tv help. - AVS Forum
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post #1 of 20 Old 02-04-2014, 04:45 PM - Thread Starter
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So I am trying to connect my laptop, Lenovo y510p, gt755mx2, 16gb ram, intel core i7 2.4ghz, to a CPX 1080p hdtv via hdmi. I am using a high speed hdmi cable and have both my laptop and the tv at 1080p at 60hz.When ever I connect my laptop to my tv one, the screen is enlarged on the tv cutting off the edges and two I get green dots flashing all over the screen. I have attached a video detailing my problem. I hope you guys can see it.

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post #2 of 20 Old 02-04-2014, 05:32 PM - Thread Starter
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Well I forgot the video but I can't seem to get it to work. I really have no luck when it come to technology. But like I said green pixels and lines appear on the screen and the tv screen flashes in and out. I have tried almost every setting on my computer and pc settings are frayed out in the tv. I have the most updates drivers for my gpu and have tried everything I could think of.
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post #3 of 20 Old 02-04-2014, 05:40 PM - Thread Starter
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Correction again, my tv is a GPX 1080p LCD HDTV.
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post #4 of 20 Old 02-04-2014, 06:18 PM
 
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Let's start with the easy one - The overscan you are seeing on the TV (where the screen is enlarged) is likely the result of a screen setting on the TV. Look for a zoom setting or crop setting. It should be something like 1:1 or Dot-by-Dot. Basically the screen is being zoomed.

To me it almost sounds like you have a bad cable and are getting bit errors. How long is the HDMI cable?

Since I can't see the video, are the two green dots over an image or do they appear or a blank screen?
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post #5 of 20 Old 02-04-2014, 06:47 PM
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Interesting. I always leave my tv set at 1:1 pixel matching. When I connect my MacBook Air to the LG with an HDMI cable, I get a control panel on the Mac that asks if I want to use the LG display. I click on it and the LG mirrors by desktop and nicely fits it to the LG panel size. Text is clear as are any movies that I choose to play. In fact, my son used to do his chemistry homework the same way using his MacBook Pro.
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post #6 of 20 Old 02-04-2014, 06:56 PM
 
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Otto, yes that is the way the system should work. One of the many differences between a CRT and an LCD (or plasma) is that the number of physical pixels match exact the highest resolution. On TVs you had scan lines and it was an analog system of a beam moving left to right and then down a line, left to right, etc. So if the number of pixels didn't match the resolution, the beam still had to traverse the line and then move down.

With a digital screen, if you don't have 1920x1080 pixels, then the screen has to decide which pixels to duplicate and which to only show a single time. It usually ends up with a screen that doesn't look sharp.
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post #7 of 20 Old 02-04-2014, 07:34 PM
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^^^^ you're up late tonight smile.gif Could it be a video card problem?
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post #8 of 20 Old 02-04-2014, 07:39 PM
 
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Quote:
Originally Posted by Otto Pylot View Post

^^^^ you're up late tonight smile.gif Could it be a video card problem?

Absolutely (up late and could be a video card problem). So let's change the advice to try a different input connection on the TV. Also try a different source device and then try a different TV, if possible.

It still sounds like bit errors but those can be generated by bad cards as well as cables.
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post #9 of 20 Old 02-04-2014, 09:34 PM - Thread Starter
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Hey guys thanks for all your help so far. I will try to take another video or some more pictures tomorrow but I am 95% sure it is not the cable. I use it for my ps3 and that works fine. My ps3 has no problems at all on this tv. And I don't think I have a bad video card. I have two graphics cards in my computer in sli. I have used my laptop on another tv with a different cable and it worked flawlessly. Cable is about 3 feet, maybe a little less idk. Like I said the pc option on the tv are grayed out and the o ly other picture setting I have access to are brightness, contrast that sort of stuff. I have tried every port on the tv flipped the cable around did a little dance and crossed my fingers but nothing. The pixels are green dots and lines that constantly run across the screen and the screen flashes in and out as if I was unconnecting and reconnecting the cable over and over. I really don't know what to do. I would just get another tv but this is the only one I have access too for the next couple of months so I want to make this work. Thanks again for your guys help.
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post #10 of 20 Old 02-05-2014, 05:29 AM
 
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I saw one thing in what you wrote that caused me to stop. When you said the "PC option on the TV are grayed out", what did you mean? Normally when you see PC on a TV, that is for the 15-pin VGA connector and not the HDMI connector. What you want to do is to hook the PS3 up and get a picture. Once you have that, disconnect the HDMI cable from the PS3 and connect it to the laptop. Normally you should not do this with the devices powered-on, but for this experiment it is required. Do not change any inputs on the TV once you have the PS3 working.

Watch the screen carefully and see if you see anything on the screen. If not, there are two more steps - first make sure the resolution on the laptop matches that of the TV. So, likely you need to make the laptop 1920x1080 - use the laptop's graphics card software to change the resolution. Then (and this is an easy step to mess up), make sure you have enabled the HDMI port on the laptop and also you have selected dual monitor mode.

That you have this working with a different TV suggests to me that that the HDMI port is enabled but maybe when you hook up the other TV the selected resolution may be different. It is important that the laptop output a resolution that the TV can recognize.

I reread what you wrote and I didn't see anywhere that you had updated the firmware on the TV and the laptop as well as the graphic's card driver. So that's a few more items to check on.

Your basically going to have to play detective and go through each item one-by-one to solve this problem. Also remember the more you tell us about what you tried, the more clues we have to help you. Please include specific model numbers when discussing components (like you already have with the TV and the laptop).
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post #11 of 20 Old 02-05-2014, 01:18 PM
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"PC option grayed out"....... I missed that. On my tv, I can change any of the HDMI inputs to a set of pre-named options. I think that enables/disables specific internal settings on the tv for the particular device's output. However, I can't change an input that doesn't have an active HDMI connection to a device. It stays grayed out until a connection is made.
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post #12 of 20 Old 02-06-2014, 06:03 AM - Thread Starter
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image.jpg 5919k .jpg file well I cannot seem to be able to upload any video u take to this god forsaken site but I do have a picture. Sorry for the crap quality it was the best one I could take with the lighting I had.
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File Type: jpg image.jpg (5.78 MB, 8 views)
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post #13 of 20 Old 02-06-2014, 09:37 AM
 
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That photo was great! Do the "anomalous" pixels ever move with a still image on the screen or do they stay at the same location over time? If they move, it is probably bit errors. If they do not move, then it is definitely not bit errors and may be a color space problem.
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post #14 of 20 Old 02-06-2014, 12:30 PM - Thread Starter
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Sorry that was all I could get with the pictures. The dots move across the screen and so does the lines.
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post #15 of 20 Old 02-06-2014, 12:34 PM
 
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Quote:
Originally Posted by ComputerNoob View Post

Sorry that was all I could get with the pictures. The dots move across the screen and so does the lines.

Like I said, no reason to apologize - picture really helped. Sorry to ask more questions but do the dots and lines move across the screen in a pattern or always in the same direction? Or, is their appearance at random locations and then they disappear and reappear elsewhere? Or something else?

Can you take two pictures maybe 10 seconds apart?
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post #16 of 20 Old 02-06-2014, 12:57 PM - Thread Starter
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Well I finally got the video to work so I uploaded it to youtube. There is one more video on my channel in addition to this one that show this issue. Sorry if the video is crap. http://www.youtube.com/watch?v=9jTfU0XexDg
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post #17 of 20 Old 02-06-2014, 01:20 PM
 
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OK. Those look like bit errors to me. So, I'm still suspecting that the cable is bad (maybe even too short). Can you take the cable that you used with the other TV and try it with this one? Basically you want to change one variable at a time. In other words, don't change the TV and the cable. First change the cable only with this TV, then try the laptop and the current cable with a different TV.

Did you try unplugging the PS3 and plugging the Lenovo in immediately afterwards?
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post #18 of 20 Old 02-07-2014, 07:32 AM - Thread Starter
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I tried taking the cable out of the ps3 and directly putting it into my laptop but nothing changes. If you could not tell from my video I am a college student so I would have to wait a little while before I can get another cable but if that is the problem then I will get a new one. I just don't understand why it would work with the ps3 but not my laptop. My computer is running two graphics cards in sli, would that cause any errors?
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post #19 of 20 Old 02-07-2014, 08:14 AM
 
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Quote:
Originally Posted by ComputerNoob View Post

I tried taking the cable out of the ps3 and directly putting it into my laptop but nothing changes. If you could not tell from my video I am a college student so I would have to wait a little while before I can get another cable but if that is the problem then I will get a new one. I just don't understand why it would work with the ps3 but not my laptop. My computer is running two graphics cards in sli, would that cause any errors?

The dual graphics cards should not cause any problems. Since you said it worked with a different TV, that should eliminate a graphics card problem anyway.

Can you borrow another cable for a test? Really a 1 minute test is all you need the cable for right now.

The reason the same cable would work with one device and not the other is that some devices have active equalization on the cable and send a more optimal signal for that cable. Some devices don't have that ability.

But, remember I'm only going down the most likely path at this point. It could still turn out to be something other than the cable.
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post #20 of 20 Old 02-15-2014, 06:21 PM - Thread Starter
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So I finally got another cable and your right it was the cable. It works perfectly fine now. Thanks for your help.
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