View Full Version : 42h83 color temperature problem
gospastic
10-10-2004, 12:25 AM
hello,
we recently purchased a toshiba 42h83. everything looks great, except for one problem that once i noticed i for the life of me cannot ignore anymore. i first noticed it while watching a black and white movie. it seems that the color temperature is not even across the entire screen. it looks a lot "bluer" on the left and more "reddish" on the right side. it's pretty gradual though, so it's only really noticeable on black and white pictures, or when i'm watching tv in 4:3 mode, in which case you can tell the the gray bars are definitely different shades of grey.
my question is, is there a way to fix this? would isf calibration fix this? what should i do? any help would be appreciated. thanks.
gospastic
10-10-2004, 12:47 AM
i've attached a picture of the problem to help explain what i'm talking about. the two circled areas show what i'm talking about.
i've tried moving around adjacent equipment, but it didn't help.
Lobstah
10-10-2004, 12:56 AM
Nothing is a sure bet, but I'd put money on a calibration if it was me.
Lob
Ratman
10-10-2004, 08:23 AM
I'd suggest that if possible:
1) exchange the set.
2) call for warranty service.
There may be more of a problem than just a 'calibration' can remedy.
kevinw
10-10-2004, 08:25 AM
All projection TV's do this. Most are not as distracting. Lens striping would cure this.
http://www.keohi.com/keohihdtv/experttips/michaeltlv/lenstriping.html
Because of the positioning of the guns, this can sometimes be noticeable, however, with a poper setup it should go away. See the FAQ "What you need to do to your new HDTV".
gospastic
10-10-2004, 11:58 AM
awesome, thanks for the links and tips. i'm gonna look into them and i'll get back to you guys. i'm just glad there's somewhat of a way to correct this. it was starting to get annoying, no matter how much i tried to ignore it.
ovalnut
10-13-2004, 11:46 AM
Lens striping can resolve this by limiting the amount of light from the edges of the red and blue CRT's, by masking the edges of those CRT's. There is, however, a price to be paid for doing so. Doing this reduces the total light output of the red and blue CRT's. In theory, you'd want to then go into the service menu and adjust at least the RCUT and BCUT parameters to account for the loss of light output. You'll also need to rerun Avia/DVE to get the brightness, contrast, color and tint levels corrected.
Once all that is done, what some people do notice is that while the red/blue edges are mostly reduced, the TV tends to show more of a bright hotspot near the center of the picture. Kinda makes sense since the edges of 2 of the CRT's have been masked off.
Due to the variety of factors affecting this tweak, and it's definite affect on the grayscale of your set, you might consider having it done as part of a full ISF calibration. Even then, a good ISF calibrator may still recommend against doing it.
Tread lightly.
Tim
:patriot:
gospastic
10-14-2004, 12:34 AM
thanks for your input on the issue. i am still considering it, the reduced light output definitely makes me think twice about it. i'm somewhat concerned about grayscale, but i know it's off anyway right now so maybe that's not a big deal. i'm pretty sure a full isf calibration is the best way to go, because at least then i can get the calibrators opinion on the matter, like you said. ah, well we will see. thanks again.
gospastic
10-22-2004, 06:18 PM
well for anyone interested, i took the plunge and opened up the tv. boy is there a lot going on in there. i tried the lens striping, which required a lot of trial and error removing and putting back and removing the screen. i got it to a point where gray on both sides was basically the same, at least to the naked eye. this will have to do for now. hot spotting in the middle ended up not being much of an issue.
thanks for everyone for their words of advice, it helped immensely.
btw while i was in there i disabled svm. being scared of getting shocked it was quite nerve racking, but worth it. picture seems a lot more natural now.
Jotmon
11-16-2004, 01:28 PM
hello,
we recently purchased a toshiba 42h83. everything looks great, except for one problem that once i noticed i for the life of me cannot ignore anymore. i first noticed it while watching a black and white movie. it seems that the color temperature is not even across the entire screen. it looks a lot "bluer" on the left and more "reddish" on the right side. it's pretty gradual though, so it's only really noticeable on black and white pictures, or when i'm watching tv in 4:3 mode, in which case you can tell the the gray bars are definitely different shades of grey.
my question is, is there a way to fix this? would isf calibration fix this? what should i do? any help would be appreciated. thanks.
the red gun resides on left and blue on the right if you see the colors predominent that means Screen bias has been increased to compensate for low LUMA drive by the CRTs the setting is so high the center of beam reflection is dominating that side of the picture . Are you sure you recieved
a brand new TV? this is usually a sign of CRT age on phosphor.
