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Discussion Starter · #1 ·
Hi Home Theater Shack! Man am I glad to find this forum.

Have a bit of an odd problem and have no idea how to solve it. I just recently bought my first HDTV, a used Mitsubishi WS-55819. The only thing we'd like to hook up to it is a laptop as all the video in the house streams and yadda yadda. Big time computer nerd, HDTV noob. Got the TV from a buddy for $100, excited that it had a VGA port on the back. Turns out it only supports 640x480. For a while, I thought we were pretty much screwed until flipping through the manual, I found that it supports RGBHV. So I murdered a few old audio cables and a VGA extension cable and hacked together a VGA to RGBHV adapter.

I get no picture and an error that reads something like "The input may be invalid". I thought I had just wasted loads of time when I restarted the computer and to my surprise, video! Briefly. While the machine boots (Toshiba Satellite A135-S4727) I get video of the POST, the TV says 480p, then as soon as Windows 7 begins loading, the video on the TV drops out. I'm assuming it's a resolution problem. I've tried everything available, from 800x600 up to 2048xsomething with different refresh rates. Part of the problem is that because I'm using the VGA port, Windows assumes it's an unidentified plug and play monitor.

As this is my first experience with HDTV, I'm pretty damned lost. I've been googling for hours but I'm not even sure what I'm looking for. I really thought all was lost until I got that POST screen. I'm guessing that's at 640x480.

Any help would be greatly appreciated! Running this huge friggen screen from SVideo seems like it should be illegal.

What resolution is required for 1080p?
Do I try to find drivers for the TV or is there some setting buried in it's menus that I'm missing?

Thanks for reading!
 

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Hopefully someone more informed will come along soon because I haven't messed with connecting my tv (CRT) to my computer in years.
Older style CRT's and computers are very difficult to get to work together. From what I remember it is the refresh rate that is the biggest culprit for not getting a picture. The CRT is very sensitive to using a certain refresh rate and the wrong refresh rate can burn something out in the tv, so the tv will shut down the picture to protect itself.
I used to use a 3rd party computer program to get all my scanning and refresh rates compatible but I can't remember what it was called.
Hopefully more useful info will come your way.

**EDIT** I looked in my CRT manual and saw that the important numbers are called Horizontal Frequency and Vertical Frequency.
 

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Discussion Starter · #3 ·
Have since tried installing different monitor drivers, including one called "Generic TV" to no avail. Pretty much at a loss here. I wonder what makes it work for a moment, then stop working? Perhaps the Horizontal Frequency and Vertical Frequency change at different resolutions? My other guess is that the frequencies are X at 480p and Y at 1080i. When Windows starts, the minimum resolution is 80x600, too much for 480p, the the frequency is not suitable for 1080i so the higher resolutions don't work either.

These are completely off the cuff, shot in the dark guesses. I haven't the faintest idea why this isn't working or even what steps to take to begin solving it.

On the bright side, over the last 16 hours, I've crammed my brain full of TV information. Yesterday, I didn't know the difference between YPrPb and RGBHV.
 

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As I said in the other thread, your computer is likely not outputing interlaced 1080i. The RGB inputs on these sets only works with 1080i and video levels. Most video cards that have the ability to output 1080i will have component adapters and not do it on the VGA outputs.
 

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I'm really shooting in the dark here, but you mention your display supports 640x480. I believe that's what your computer outputs for its splash screen during the boot-up (as you guessed), and it then switches to whatever resolution has been specified as normal by your computer video card (which you set in Settings).
If your display only supports 640x480, it's not HDTV at all. It's a computer monitor and that's (640x480) one of the standard computer resolutions used (VGA???). The trick to getting a picture (which won't be HDTV) is to send a format from your computer that is 640x480 and that would be controllable from your computer settings and determined by the capabilities of your computer video card. In any case, to get real HDTV, you need a 1080x1920 capable monitor and a respective computer video card setting which may or may not exist in your specific computer. Hope this helps.
 

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Discussion Starter · #6 ·
Quick update, have downloaded a program called PowerStrip and while messing with the Display Profiles, have gotten 480p to work using 640x480 resolution.

Here's where it gets even more confusing. Under another custom 640x480 profile, the TV switched over and said "1080i Standard". I'm not real sure how that's happening, but seems like good news? The drawback is that the picture seems 4:3 with black bars on either side.

Is it possible for the TV to be in 1080i while only sending 640x480? I've tried a few of the 1920x1080 settings and the TV doesn't much like those.
 

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This set IS HD. It only supports 640x480 on the VGA input. It would accept 1080i on the discrete RGBHV inputs, but only as interlaced HD, not as progressive higher resolutions for computer output.

This set was a little unusual by today's standards. It was designed in the very early days of consumer HD, when it was uncertain what kind of outputs would become the norm. For instance, the first RCA HD sat receivers used a discrete RGB output, rather than component. The set had an external DTV tuner available that used the discrete inputs as well.
 

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Discussion Starter · #8 ·
Yes sir, I'm using the RGBHV input. Played around some more and it's still reporting 1080i, resolution I've got PowerStrip at is 1800x480.

I'm using the laptop mentioned above (Intel GMA950 video chipset), Sherry 1.3 945 drivers, and PowerStrip. It allows me to send RGBHV interlaced, apparently even being able to control h and v sync polarity.

The last problem I'm dealing with here is trying to get the video to not look all scrunched up. Everything is sort of smashed in to 4:3, making everything look tall and thin.

Also, I don't completely understand how I can send anything other than 1920x1080 and have the TV set to 1080 and it work. Is something scaling pixels?
 

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Your video card is probably set for 4:3 timing. Does it allow you to adjust sync intervals?
 

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Discussion Starter · #10 ·
I believe so. These are the screens I'm working with (from a completely unrelated topic, same program though)
edit: lets try one in english



and:
 

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You appear to have an aspect ratio setting for 16:9, which is what you need for HD.
 

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Discussion Starter · #12 ·
Those aren't my settings or computer, just the program I'm using. I've tried messing with just about every setting in there, seems the best I can do is really zoomed in vertically and squished horizontally. I'm missing ~half the image vertically (top and bottom), and the picture is about 4:3.
 

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Discussion Starter · #14 ·
I think the problem I'm having right now may be with the video card itself. I've read that PowerStrip works fine with the Intel GMA950, some other posts say that it doesn't work so great.

So far, the best I've got:
480p working at 640x480 over VGA to RGBHV
1080i with black vertical bars stuck in 4:3 at a few different resolutions.

Currently trying to write my own DTD using info found in forums and the DTD calculator to include in an INF. All the fooling around with drivers and resolutions has left my registry absolutely full of invalid DTDs. Will be rolling back to factory and starting from there, will report back.

Anyone that has a DTD for Mitsu 55819, by all means, post them here. Looking for 1920x1080i at 1080 timings or 1280x720
 

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PowerStrip is that program I used with my Pioneer CRT years ago. I can't remember what computer video card was being used.
I got settings information for my tv from a PowerStrip forum that worked great. Hope it works for you.
 
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