CRT TV will accept real NTSC signal via RGB/scart but not composite only

Discussion in 'General Gaming' started by keropi, Sep 28, 2012.

  1. keropi

    keropi Familiar Face

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    Hello!

    I have a 14" trinitron tv set that I started using for retro gaming. I had to go to service menu and open the NTSC signal acceptance ability and it works fine with real ntsc machines in rgb-scart mode.
    I wanted to test my CDX via composite and found out that it does not work... I get a white blank screen, switch cables to an rgb one and all is great again. I tested the console on my 37" lcd set and it works fine in ntsc composite (as expected...)
    I wouldn't really bother much , but I am waiting for a famicom to arrive and it will work through composite so this won't display on my 14" set :dejection:
    Is there a solution?

    I have seen on eBay some 30$ ntsc<->pal converters, assuming I get one do they add any kind of lag? Is there a way to make my own converter? 30$ seems overpriced...

    Thanks in advance for any info/help! :smile-new:
     
  2. Bad_Ad84

    Bad_Ad84 The Tick

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    RGB isnt NTSC. RGB is RGB.

    A NTSC console via RGB will be RGB/60


    Basically, your TV is not accepting NTSC, its just accepting 60hz and RGB
     
    Last edited: Sep 28, 2012
  3. keropi

    keropi Familiar Face

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    ^ something like that it seems.... in more detail:

    Before enabling NTSC:
    -> I could run for example my PAL SNES, PAL SATURN and MD1 with both 50 and 60hz rgb modes. (not a 1CHIP snes with a ntsc crystal , haven't tested it)
    -> I could not run CDX from scart-rgb, it would show the blank white screen

    After enabling NTSC:
    -> PAL consoles worked as before in 50/60hz rgb modes
    -> CDX was showing an image in rgb mode

    If I disable NTSC then CDX stops showing an image. Maybe it's a 50% NTSC support in rgb or something...
     
    Last edited: Sep 28, 2012
  4. Bad_Ad84

    Bad_Ad84 The Tick

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    NTSC and PAL are colour encoding. RGB doesnt encode the colour (its raw - which is why its so good)
     
  5. 7Force

    7Force Guardian of the Forum

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    Just think of RGB as a "region free" video signal.
     
  6. keropi

    keropi Familiar Face

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    Guys you are missing the point here.... I know the color encoding is different, I am just stating that my tv set needed the NTSC option for NTSC RGB from a real NTSC machine to work so you have the whole story. Without NTSC option my set would not display an rgb signal from an ntsc machine. That will never change for this tv set.

    Is using an eBay NTSC->PAL compostite converted my real option here? Does it degrade the signal or add lag? anyone knows this?
     
  7. Lum

    Lum Officer at Arms

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    It probably means your TV uses composite video to sync RGB. That line would have a slightly different signal between NTSC and PAL machines.

    I happen to own an HDMI converter who won't take RGB without color subcarrier. Annoying because that mod can reduce Master System and Mega Drive vertical bars. :(
     
    Last edited: Sep 28, 2012
  8. andoba

    andoba Site Supporter 2014

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    I might be saying stupid but you could maybe put a composite sync stripper between your composite video line.
     
  9. keropi

    keropi Familiar Face

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    I just thought of this: wouldn't those ntsc->pal converters also make the signal go from 60hz to 50hz? that can't be good for gaming use, right?
     
  10. reprep

    reprep Gutsy Member

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    No, they are not. They just change the colour encoding.

    NTSC to PAL converter, change NTSC60 to PAL60 (fortunately most PAL sets support that, except my Samsung HDTV)

    PAL to NTSC converter, change PAL50 to NTSC50 (mostly this is not supported on NTSC sets)
     
  11. MangledLeg

    MangledLeg Peppy Member

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    Just a thought - maybe the TV is saying "NTSC", but it actually means its readying itself for a 60hz signal, hence the combo. As others have said, PAL/NTSC contains two portions to the standards if you simplify things - refresh rate and colour encoding. PAL standard is PAL colour encoding (or using a 4.43mhz clock) at a 50hz refresh rate; NTSC is NTSC colour encoding (using a 3.56mhz clock) at a refresh rate of 60hz.

    PAL60 retains the positive points around the PAL colour encoding and marries it with a 60hz refresh, therefore best of both worlds.

    RGB (whether delivered via SCART or any other socket/plug) is purely a discussion on colour encoding, as there is no set refresh rate (so, you could have horizontal refresh rates of 50hz, 60hz, 85hz, etc, and combinations of vertical refresh rates such as 15khz, ~24khz or 31khz [often used when talking about arcade monitors[).

    Your discussion so far suggests that your monitor is happy to accept PAL video over composite at 50hz, RGB at 50hz and, when enabling NTSC mode, RGB at 60hz.

    So, if I'm on the right path, I'd suggest trying to play a PAL console outputting a PAL video signal over composite at 60hz and see what happens. If the PAL machine displays correctly, it means the TV is happy to work with a PAL60 signal. This means that if you transcode the Famicom's composite video from NTSC colour encoding to PAL colour encoding, it should work.

    If PAL60 won't behave with your monitor, you'll need to find a way to transcode the signal from NTSC@60hz to PAL (at 50hz). Not sure what's out there in the market, but Panasonic had a range of VCRs around 2000/2001 that would actually convert NTSC and PAL60 on the fly to PAL50 - we used to use it back in the day to play NTSC consoles on a PAL TV that only had RF input :)
     
  12. keropi

    keropi Familiar Face

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    @reprep: thanks for the info, it is very helpfull

    @MangledLeg : my tv works fine with PAL and PAL60 as I have stated before and it has no problems with it in all connections (rgb, composite, svhs)
    When I enabled NTSC it also worked with ntsc-rgb but not with ntsc-composite. That's my problem, not pal60, not ntsc-rgb but ntsc-composite and only this. :)
     
  13. reprep

    reprep Gutsy Member

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    according to the info you gave, a 30$ NTSC to PAL converter will do your job. You will have NTSC60 input to the device and you will have PAL60 output which your TV accepts.

    But i would always try to find ways to use RGB when available. Composite is really bad.
     
  14. keropi

    keropi Familiar Face

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    yes, I prefer rgb too but when it comes to a 1st generation famicom then composite is actually the only way if you don't want to spent hundreds of $$$ :)
     
  15. MangledLeg

    MangledLeg Peppy Member

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    Cool, just wanted to clarify exactly what situation you were in, since there's no such thing as NTSC RGB (NTSC is a colour encoder, not a refresh rate) and your monitor suggests that "NTSC" is actually telling the CRT to accept a 60hz video signal.

    So reprep is on the case - grab a transcoder/converter to re-encode the colour from NTSC to PAL and you should be fine. Just make sure the converter doesn't touch the refresh rate :)
     
  16. reprep

    reprep Gutsy Member

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    I recently had a look at ebay for these converters and all ones at about 30$ just change the color carrier and keep the refresh rate as i said above. Refresh rate change is not recommended as it will ruin your gaming experience plus you will have to pay much more for a converter which has this ability. Because a buffer is needed for this function.
     
  17. keropi

    keropi Familiar Face

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  18. MangledLeg

    MangledLeg Peppy Member

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    Nice idea on internalising the converter :) Might be handy to fit a switch as well in case you want to take the conversion path off down the road. As long as your power supply has enough amps to cater for the Famicom and the converter, sounds like it would work. The only issue I could think of is noise being emitted by the device if it's mounted internally, but I don't have the much knowledge on the side of things so perhaps other more experienced modders could offer feedback on that.
     
  19. keropi

    keropi Familiar Face

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    Today I received the converter... the picture quality is STUNNING and looks like RGB on the 14" tv , BUT... look at the vid I made:



    the converter only displays 1 frame/sec, possibly worse! It's totally useless.
     
    Last edited by a moderator: May 25, 2015
  20. la-li-lu-le-lo

    la-li-lu-le-lo ラリルレロ

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    Maybe I'm misunderstanding the discussion here, but something occurred to me. If you're using composite video as sync for RGB, then that signal has to be either PAL or NTSC, right? And I would assume that European TVs do not normally accept NTSC composite video as sync. If that's the case, you probably don't even need a transcoder, just a sync-stripper (assuming the TV supports C-sync). Is that the issue here, or am I missing something?
     
    Last edited: Oct 17, 2012
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