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LCD VS Spectrum +2A/B+/+ RGB

odiousodious
edited May 2010 in Hardware
What is the problem with LCDs and spectruns?

I've had no problem connecting RGB leads getting an excellent picture on crt's but, why the heck LCDs work fine with megadrives, snes, xbox's and whatmore but simply refuse to work properly with a +2B or +2A?

I'm not the only one noticing this, if you look around, a lot of users are having the same problem....

I'ts not the cable, it's not the spectrum. It's the fucking lcds, but why?
Post edited by odious on

Comments

  • WinstonWinston
    edited May 2010
    My +3 works excellently with an LCD TV. The picture quality is amazingly good. You need an LCD with a native resolution well above that of the Spectrum and a good ability to smooth images at non-native resolutions to avoid highly visible aliasing problems. A 1280x1024 native resolution is the best, but 1024x768 seems to do well.

    It might be certain brands of LCD that are problematical.
  • batsilosbatsilos
    edited May 2010
    Look at the back of the LCD and check if they have a second scart euroconnector. Try connecting it there. Some euroconnectors do not follow the standard Scart pinouts.
  • orangeorange
    edited May 2010
    for starters, you didnt say what exactly the problem is, are you getting no picture at all?

    if so, you need to take care of BLANKING pin on SCART (supply it with 1 to 3 Volts), to force the LCD to switch to RGB and not composite mode. I think that should fix it, that was the case with my plasmaTV.


    also, check out this wonderful manual: http://mts.speccy.cz/doc/128_rgb.pdf
  • odiousodious
    edited May 2010
    Winston wrote: »
    My +3 works excellently with an LCD TV. The picture quality is amazingly good. You need an LCD with a native resolution well above that of the Spectrum and a good ability to smooth images at non-native resolutions to avoid highly visible aliasing problems. A 1280x1024 native resolution is the best, but 1024x768 seems to do well.

    It might be certain brands of LCD that are problematical.

    I get mixed results but i'd be happy if it was only antialising. It's a variety of behaviours such as black lines appearing randomly across the image, or gohsting, or rolling on various sets were, for example, a mega drive behaves flawlessly.


    batsilos wrote: »
    Look at the back of the LCD and check if they have a second scart euroconnector. Try connecting it there. Some euroconnectors do not follow the standard Scart pinouts.

    I am aware of that, normally only one of the connectors is able to take RGB in.
    orange wrote: »
    for starters, you didnt say what exactly the problem is, are you getting no picture at all?

    if so, you need to take care of BLANKING pin on SCART (supply it with 1 to 3 Volts), to force the LCD to switch to RGB and not composite mode. I think that should fix it, that was the case with my plasmaTV.
    also, check out this wonderful manual: http://mts.speccy.cz/doc/128_rgb.pdf


    As above, i am getting a lot of unsatisfactory results, even after getting the blanking down to 1V (ok 1,05V).

    What bugs me is that crt's output an amazingly good picture where the same cable and +2B gets either lines, or rolling images, or ghosting on several lcd tvs. On the other side, these LCD tv work flawlessly through RGB with other machines (dreamcast, playstation, mega drive... even a modified sms2).


    Bah, rgb should be straight standard, plug and go.
  • csmithcsmith
    edited May 2010
    The speccy has a fake vertical sync signal. Great for resetting the vertical sweep oscillator of analogue tvs but perhaps not great for digital tvs that expect a specification vsync. I know of some tvs with problems, but not the effects you are reporting... Doesn't mean it's not related though.
  • BiNMaNBiNMaN
    edited May 2010
    My +3's (and +2a/b's) suffer the same on my big LG the image is just obliterated, no problem on a 19" Goodmans, my 19" Bush (no jokes boozy!) gives a vector effect bit like realspectrum can do on one of it's video modes.

    (someone will correct this I'm sure) toastracks and grey +2's seem to put out the rgb slightly differently, now I have no problem (as yet) with them on any of my lcd tellies
  • odiousodious
    edited May 2010
    So, it's a combination of weak or off-the-chart signals from the spectrum and precision demand from the lcd tvs.

    Composhit can always be an option but, rgb outputs the best image.

    I'll keep my big rear ended crts well treated then.
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