Image Map Image Map
Page 3 of 3 FirstFirst 123
Results 21 to 28 of 28

Thread: MAME Cabinet Build

  1. #21

    Default

    The sub-brightness is too high. No current=no light.

  2. #22
    Join Date
    Jan 2005
    Location
    Principality of Xeon (NJ)
    Posts
    1,417

    Default

    As soon as power is supplied to the unit, the guns are continually scanning. This much I know. To say there's that there's absolutely positively no leakage or whatever seems unlikely. Some faulty monitors do nothing but glow when you turn them on.

  3. #23

    Default

    Grid is sufficiently negative, zero electrons pass.

  4. #24
    Join Date
    Apr 2015
    Location
    Austin, Texas
    Posts
    1,717

    Default

    Quote Originally Posted by tipc View Post
    It's kind of apples and oranges, but lcd's do scan similar to crt's. Hence the refresh rate which presumably is as critical or more so with lcd's.
    Refresh rates are not at all important to LCDs, which is why the introduction of desktop LCD panels in the early to mid 2000s set back video technology for over a decade. CRTs had always been able to run at very high refresh rates, and by the time of their demise, 75-200 Hz was common, with higher refresh rates being available on higher end monitors. Manufacturers used the fact that LCD pixels are persistent until changed, so they determined with a backlight, there was no need to attain such high refresh rates. This dropped refresh rates back down to 60 and sometimes 75 Hz until the early to mid 2010s when LCD displays finally started ramping up refresh rates again due to HD content becoming a norm.

    Quote Originally Posted by tipc View Post
    This KDS isn't particularly hot. This asus 21.5" lcd has some use on it, but has that same "splendid" sticker I still see at Best Buy. Overall the kds looks noticeably dim by comparison. But it's blues and magentas are richer. Put a trinitron up against a more or less revent lcd and you have a basis for comparison. The kds is kind of drab. But at least it has "depth"
    KDS is a cheap garbage brand, their CRTs had high failure rates due to crappy flyback transformers that would often short out due to bad corona dope insulating the high voltage windings.

  5. #25
    Join Date
    Jan 2005
    Location
    Principality of Xeon (NJ)
    Posts
    1,417

    Default

    All I know is lcd's are rated for their response time, in the milisseconds. Modern lcd's must hav different levels of persistence, and perhaps call for a higher refresh rate. These high end monitors which have response times in the single digits, and are much sought after by gamers, can't possibly have the same persistence you're talking about. If the image persists for too long, refresh to a large degree and response times, or whatever the exact terminology is, are of no consequence. Some professional gamers make millions of dollars, and you can be pretty sure they're no gaming on run of the mill lcd's.

    Crt's and lcd's are 2 different animals clearly. Many people just aren't aware that a type of vertical and horizontal scanning goes on just like a crt. But as to the visible absence of scan lines on lcd's, it's something I haven't noticed or paid much attention to.

    I have seen KDS monitors work for years in a 24/7 situation. Not at all stating they're top of the line. My point was even on such a brand, the benefits of using a crt seem obvious. Pluses and minuses with both though.

  6. #26
    Join Date
    Apr 2015
    Location
    Austin, Texas
    Posts
    1,717

    Default

    Quote Originally Posted by tipc View Post
    All I know is lcd's are rated for their response time, in the milisseconds.
    LCDs have two ratings, the response time (which is how long it takes for an LCD pixel to change color) and refresh rate (in hertz) of how many times the entire screen can refresh per second. Different LCD technologies are better and worse in different areas. TN panels are better in response time but have awful color reproduction, IPS panels are better at color and worse at response times and VA panels try to get a happy medium.

    Quote Originally Posted by tipc View Post
    Modern lcd's must hav different levels of persistence, and perhaps call for a higher refresh rate. These high end monitors which have response times in the single digits, and are much sought after by gamers, can't possibly have the same persistence you're talking about. If the image persists for too long, refresh to a large degree and response times, or whatever the exact terminology is, are of no consequence. Some professional gamers make millions of dollars, and you can be pretty sure they're no gaming on run of the mill lcd's.
    ALL LCD panels have persistence, it's how the technology works. Once a pixel is changed, it will retain that state so long as power is applied, or the display controller changes it. This is unlike a CRT where the phosphor immediately starts losing intensity once the electron beam moves past it, which makes refresh rate very important on a CRT to avoid flickering/strobing. People getting headaches on low refresh rate CRTs was a problem that LCD monitors never had because there was always something on 100% of the screen at all times.

    Quote Originally Posted by tipc View Post
    But as to the visible absence of scan lines on lcd's, it's something I haven't noticed or paid much attention to.
    You can't see scan lines on LCD panels because they don't exist. The only thing you'd see if you had a high frame rate camera looking at an LCD screen is pixels changing color for the above explanation.

    Here's a video showing the difference: https://www.youtube.com/watch?v=3BJU2drrtCM

  7. #27
    Join Date
    Jan 2005
    Location
    Principality of Xeon (NJ)
    Posts
    1,417

    Default

    Ok well staring at the KDS real close, 800 x 600, can't go any higher, video drivers aren't functional, I guess I see what you're talking about. Which may be why I guess there's a distinct difference between lcd's and crt's in my eyes. The density if you will of an lcd's image makes it look like solid color on a print or what have you (as in an artist print). Which makes it look "flat" to me. Or some horsecrap, I don't really know or care at this hour!

  8. #28
    Join Date
    Apr 2015
    Location
    Austin, Texas
    Posts
    1,717

    Default

    The image in a CRT is farther back than an LCD panel. LCD panels are as thin as a piece of plate glass and the pixels are generally on the back of the plate.

    In a CRT, the image is on the phosphor layer, which is probably 4-10 times the distance back inside the vacuum tube. The glass on the front of the tube is super thick because it has to withstand the tons of pressure exerted on the face from the vacuum inside the tube. The implosion ring around the face is there to keep tension on the face and give it more strength.

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •