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View Full Version : How do you fix shadowing problems on a CRT?


Porcupine2
02-22-06, 04:39 PM
I don't know what is the exact terminology to describe this particular image problem, but I think it could be called a shadowing effect. Some people might call it ghosting but I'm not sure that refers to the same phenomena. I see this to a very very minor extent on almost all CRT TVs but rarely is it a problem. I don't know if this problem is specific to CRTs, but maybe it is not, because I've also seen this same problem come from analog ESPN Classic, only that one channel, and it was very severe. So the problem originated, in that case, from the broadcast station. Although the TV itself generally adds to this exact same problem (but usually by an unoticeable amount).

Usually what it looks like is that when there are sharp color transitions, the colors sort of bleed or create shadows to the right. But it's not the same phenomena as bleeding (which only occurs when the TV is turned too bright). I don't think this phenomena is ringing either, although that's another phenomena that can sometimes look similar.

The reason I'm wondering is that I have a Dell 20" Trinitron computer monitor, which shadows a bit. It's not severe but it is noticeable. It used to be perfect, until I had it shipped (I moved) over and when it arrived, I could tell it had been dropped. The base was cracked, and this shadowing problem appeared. (I got some money from insurance, so that was good). I'm wondering if there is any way to fix this problem. Anyone have any ideas what this problem is and how it might be fixed? BTW there are no sharpness controls on this monitor so I don't think ringing is the phenomena I'm seeing.

Another problem that occured with my monitor after it had been shipped/dropped, was that the lower right corner became fairly noticeably discolored. It's not awful, though. It looks a lot like magnetic discoloration and is permanent. I've tried some weak attempts at manual degaussing (with hand magnets) but they seem to have no effect. I don't know if this problem is also because my monitor was dropped, or whether something else is the cause. I do have (shielded) speakers and stuff around but I've tested them and they aren't the cause.

kny3twalker
02-22-06, 08:56 PM
over compressed channels on DirecTV cause even the best deinterlacer to have problems

I had for a long time problems with speed, which DirecTV seems to have now corrected

ESPN Classic seems to be another over compressed channel

squonk
02-23-06, 02:47 AM
Its a very prickly problem Mr Porcupine.

Porcupine2
02-23-06, 04:29 PM
The problem I'm referring to occurs only with analog ESPN Classic I think, through regular analog cable (if you still get analog cable, like I do). I don't see any signs of digital compression on this channel.

dallas27
02-23-06, 04:37 PM
I think everyone has this problem. For instance white letters on a black backround, white "sparkles" will be to the right of every letter, like there on fire or something.

I notice it's only usually there when at full white too, that is the the letter start to "fade to black" it immediately dissappears.

I don't think this is your TV (or mine) I think it's just a problem somewhere in the sorce. You'll notice commecials do it the most, becuase they would be using the cheapest hardware to keep down costs.

Porcupine2
02-23-06, 04:46 PM
I agree that everyone has this problem to a certain (minor) extent. I'm just wondering what causes it and if there is a way to make it better. It's not an issue for most TVs I've seen, but I have that one computer monitor that was dropped and got slightly out-of-wack, and I'm wondering if it can be fixed.

I think this problem can originate from both the source (analog ESPN classic example) or the CRT (my dropped monitor, plus it is displaying a clean computer signal so if it is still the "source" that can only mean the computer's video card or perhaps the cables).

I also only notice this problem on certain kinds of lightish backgrounds and sharp color transitions.

BTW I just checked analog ESPN Classic just now and they fixed this problem. It was probably only affecting them for the last month or so (it affected all their programs if I remember correctly).