How black is black?

bazzae123 · 12-05-2003, 12:08 AM

I have an engineer coming to look at the geometry on the new tube fitted to my Toshiba 32ZD08B but I'm also concerned about the level of greenish tinge I can see either side of the picture when in 4:3 mode. The blackish vertical bars appear to be greenish and change in intensity depending on the picture being displayed. Is this normal? The problem is the last tube I had a reddish tinge so the tube was replaced. Now is greenish. How black should they be?

I need to be armed with as much info as possible before the guy turns up so that I'm not blinded with science or given the brush off.

Bazza

12-05-2003, 1:02 AM

My TV (RP) has three pots that adjust the intensity of each gun, I've never tried adjusting a direct view this way - usually the RP's have them in a easy access area.

I guess yours will be the same. The pots will probably be near the neck of the tube, one the little PCB.

I've adjusted the R slightly, if I increase too much the black widescreen border becomes red- everything else goes red. So I put to the correct level.

12-05-2003, 5:41 AM

It should not have any colour bias at all in my experience. My toshiba is neutral in this respect. The intensity of these bars will change a bit if the scene is very dark or bright, but it shouldn't be that noticeable, so I wonder if you are running the screen controls too high, though this won't give you green blanking bars on 4x3, that is another issue. What brightness/contrast levels are you using?

There is no electronic (user) adjustment for colour levels on any modern direct view tv that I'm aware of. They are usually factory set by computers. These will be accessible in the service menu though I would not go in there unless you know what you are doing because altering the wrong parameter could cause mayhem. If the engineer is serious he will have a meter that will check the white balance and a pattern generator to see if the tv is working correctly.

One other thing: if the crt was changed but the tv wasn't set up again with the new crt this MAY account for the colour balance changing, but this is only a long shot. All crt's have different gains on the red/blue/green level so this should have been done as a matter of course. I would be amazed if the tv wasn't fully tested and adjusted after that sort of surgery.

bazzae123 · 12-05-2003, 6:57 PM

Thanks guys,

I reason for the engineer being called in the first place is to adjust the geometry. It's so far out you wouldn't believe it ever left the workshop. Looking at the football result tables on Sunday on Sky, there wasn't a straight line in slight and this was in 4:3 mode.
I took delivery of the set of Friday but it wasn't until Friday night when the light level was lower that I noticed the green tinge to the picture and especially the black bars either side of a 4:3 screen mode. I can't seam to get a colour setting that I'm happy with either. I did find a colour bar test on Satellite and the whites are not clean but a slight greyish. Anyway, I've just spoken to the repair shop (Toshiba authorized in East Anglia) and told them about it and advised the engineer to bring any equipment needed to do the adjustments. I'll put money on it he just turns up with a screw driver!!

Bazza

12-05-2003, 1:02 AM	#2
nathan_silly Guest Posts: n/a	My TV (RP) has three pots that adjust the intensity of each gun, I've never tried adjusting a direct view this way - usually the RP's have them in a easy access area. I guess yours will be the same. The pots will probably be near the neck of the tube, one the little PCB. I've adjusted the R slightly, if I increase too much the black widescreen border becomes red- everything else goes red. So I put to the correct level.
	Quote

12-05-2003, 5:41 AM	#3
Knickerzohnonov Guest Posts: n/a	It should not have any colour bias at all in my experience. My toshiba is neutral in this respect. The intensity of these bars will change a bit if the scene is very dark or bright, but it shouldn't be that noticeable, so I wonder if you are running the screen controls too high, though this won't give you green blanking bars on 4x3, that is another issue. What brightness/contrast levels are you using? There is no electronic (user) adjustment for colour levels on any modern direct view tv that I'm aware of. They are usually factory set by computers. These will be accessible in the service menu though I would not go in there unless you know what you are doing because altering the wrong parameter could cause mayhem. If the engineer is serious he will have a meter that will check the white balance and a pattern generator to see if the tv is working correctly. One other thing: if the crt was changed but the tv wasn't set up again with the new crt this MAY account for the colour balance changing, but this is only a long shot. All crt's have different gains on the red/blue/green level so this should have been done as a matter of course. I would be amazed if the tv wasn't fully tested and adjusted after that sort of surgery.
	Quote