Custom Resolutions & Refresh Rates on CRT TV (CRU)

[RVZ]

I'm trying to connect my pc to an LG 29FS4RLE CRT television.  I've tried both Nvidia (GTS450) and ATI (6000 series) cards, both HDMI to HDMI-to-Component transcoder, to component input on TV. 

I'm struggling to get a clear image though, just getting a 'rolling / scrambled' image.  On the ATI card there is a resolution of 720x576 @ 25hz, which gives an clear image, but it's flickering quite a lot with an overscan.  On the Nvidia card I once managed to get very good images, without flickering, but every time I rebooted it would be gone again.  I used CRU for setting up the custom resolutions and refresh rates, but after all this messing around and swopping cards, I can't get it working again.

How can I find out what the settings should be for setting up different refresh rates? 

[Arroyo]

I'm trying to connect my pc to an LG 29FS4RLE CRT television.  I've tried both Nvidia (GTS450) and ATI (6000 series) cards, both HDMI to HDMI-to-Component transcoder, to component input on TV. 

I'm struggling to get a clear image though, just getting a 'rolling / scrambled' image.  On the ATI card there is a resolution of 720x576 @ 25hz, which gives an clear image, but it's flickering quite a lot with an overscan.

Assuming your TV isn’t very unique that resolution is too high for a standard definition TV.  Avoid continuing that resolution as it can damage the circuitry.

I see from one of your earlier posts that you had planned on using CRT_emulation driver.  This is a driver written for Windows that will allow you to access the lower resolutions you need for the TV.  This driver is specifically for ATI cards, so the NVIDIA is no good.

If you follow the tutorial online exactly this will help you get the resolutions you want. AND setup proper refresh rates.

You also should read up on connection types to the TV.  Your ATI card should have a D-Sub (VGA) output.  This will give you analog out.  The HDMI transcoder could work but I’d be careful to make sure it doesn’t force a resolution output.  Normally you’d get an analog transcoder and use the D-Sub connection to get the signal to the analog transcoder and then to your TV.

[RVZ]

I'm trying to connect my pc to an LG 29FS4RLE CRT television.  I've tried both Nvidia (GTS450) and ATI (6000 series) cards, both HDMI to HDMI-to-Component transcoder, to component input on TV. 

I'm struggling to get a clear image though, just getting a 'rolling / scrambled' image.  On the ATI card there is a resolution of 720x576 @ 25hz, which gives an clear image, but it's flickering quite a lot with an overscan.

Assuming your TV isn’t very unique that resolution is too high for a standard definition TV.  Avoid continuing that resolution as it can damage the circuitry.

I see from one of your earlier posts that you had planned on using CRT_emulation driver.  This is a driver written for Windows that will allow you to access the lower resolutions you need for the TV.  This driver is specifically for ATI cards, so the NVIDIA is no good.

If you follow the tutorial online exactly this will help you get the resolutions you want. AND setup proper refresh rates.

You also should read up on connection types to the TV.  Your ATI card should have a D-Sub (VGA) output.  This will give you analog out.  The HDMI transcoder could work but I’d be careful to make sure it doesn’t force a resolution output.  Normally you’d get an analog transcoder and use the D-Sub connection to get the signal to the analog transcoder and then to your TV.

Thanks for the reply.  Yes, I was looking at using the CRT emudriver, but I'm struggling to find a transcoder for it. It's difficult getting international shipping through our local postal service, everything seems to go missing along the way.  I've ordered 2 VGA to component transcoders from ebay, which should work, but none of them arrived yet.

So until then, I'm trying with the hdmi solution, even if it's not the same resolutions as what I can get with emudriver.

How can I prevent the CRT from getting damaged from playing around with the resolutions and refresh rates?  And how easily can it happen? 

[Arroyo]

Thanks for the reply.  Yes, I was looking at using the CRT emudriver, but I'm struggling to find a transcoder for it. It's difficult getting international shipping through our local postal service, everything seems to go missing along the way.  I've ordered 2 VGA to component transcoders from ebay, which should work, but none of them arrived yet.

Where are you located?  Does your TV have a Scart input?

How can I prevent the CRT from getting damaged from playing around with the resolutions and refresh rates?  And how easily can it happen?

Until you can output a 640x480i (or 640x240p) signal as confirmed by your graphics card in Windows video output then I wouldn’t connect your TV.  That won’t happen until you’ve gone through the steps of installing the CRT_emulation drivers and use your ATI card.  You would need to select the HDMI output if that is available, but I haven’t done that before, only the VGA.  I know that on some cards this is an option, but usually the HDMI cable is connected to a Digital to Analog converter and then to the TV from there.

First thing I would do is get confirmation that the drivers have installed properly and that you get the correct setting for resolution output.  Then worry about the transcoder.  Which one did you order?

[RVZ]

I'm in South Africa.  No scart.  So far I've ordered this one last year already,

https://www.ebay.com/itm/174085772114

And this one last month,

https://www.ebay.com/itm/193049027689

Is it possible that the TV might already be damaged, or will it not display anything if it is?

[RVZ]

This is why I tried with the hdmi converter.

https://www.reddit.com/r/crtgaming/comments/awqolc/get_high_quality_240p_from_your_pc_to_your_tv/?utm_source=amp&utm_medium=&utm_content=post_body

According to him you can get 240p on any card, not just ATI.

[Arroyo]

I'm in South Africa.  No scart.  So far I've ordered this one last year already,

https://www.ebay.com/itm/174085772114

And this one last month,

https://www.ebay.com/itm/193049027689

Is it possible that the TV might already be damaged, or will it not display anything if it is?

The first one looks good, not so confident in the second one.  The first one specially says it does not convert the image, just the color space which is what you want.

The second one doesn’t state that so I’m guessing it coverts to a static forced 640x480i which if so is not what you want as you can’t then get resolution switching going.

You can test the TV with a DVD player if you have one handy to make sure it works well.  Unless you’ve done it a lot for extended periods I’m guessing you will be fine.

[Arroyo]

This is why I tried with the hdmi converter.

https://www.reddit.com/r/crtgaming/comments/awqolc/get_high_quality_240p_from_your_pc_to_your_tv/?utm_source=amp&utm_medium=&utm_content=post_body

According to him you can get 240p on any card, not just ATI.

That will probably work for a static 640x240p (read consoles), but to get the resolution switching you match GroovyMame with CRT_Emulation driver to get resolution switching going as well as Variable Refresh rates which make sure the game is running at the correct speed.

[buttersoft]

According to him you can get 240p on any card, not just ATI.

It's a fine theory. He's talking about pixel clocks over 25Mhz tho, which means using larger horizontal "super" resolutions, like 2560x240@60p (anything over 1600 pixels wide should work). I presume this is the lower limit of the dot clock some GPU's would output. Or some GPU he owns or something. Not to be harsh, but it's hardly a universal solution, these kind of posts never are.

[RVZ]

According to him you can get 240p on any card, not just ATI.

It's a fine theory. He's talking about pixel clocks over 25Mhz tho, which means using larger horizontal "super" resolutions, like 2560x240@60p (anything over 1600 pixels wide should work). I presume this is the lower limit of the dot clock some GPU's would output. Or some GPU he owns or something. Not to be harsh, but it's hardly a universal solution, these kind of posts never are.

I get that it's not the ideal solution.  My plan is definitely to use the CRT Emudriver with GroovyMame, IF I ever get an VGA to Component transcoder.  Until then I'm just looking for the next best looking solution, which I'm guessing is converting HDMI to Component?  Or am I missing something else?

For setting up custom resolutions and refresh rates, how are you suppose to know the settings for things like Front Porch, Sync Width, Back Porch etc???

[Arroyo]

Until then I'm just looking for the next best looking solution, which I'm guessing is converting HDMI to Component?  Or am I missing something else?

There is also RGB modding the TV which involves looking up the schematics for the Jungle Chip on the TV’s chassis and then wiring in the RGB outputs from the VGA cable.  Might not be something you want to do if you don’t have any knowledge/experience with CRT’s, but it is an option.

Here’s someone on here going through it right now: http://forum.arcadecontrols.com/index.php?topic=161834.0

For setting up custom resolutions and refresh rates, how are you suppose to know the settings for things like Front Porch, Sync Width, Back Porch etc???

It takes some playing with but once you get the hang of it the On Screen Display for it gives you all the visuals you need to make it work.  All you are doing is shifting the right and left sides of the image until they fit your display properly.  If you use Super Resolutions you don’t have to set up custom resolutions GroovyMame picks the appropriate one and you are done.

[buttersoft]

Yes, that's true. Using crt_emudriver is a good way to learn about modeline timings. I did it with analog video/VGA, but i don't see the process being too different with HDMI.