CRT contrast

[andykara2003]

Hi all, I have two Sony KV-14LT1U 14”
Consumer CRTs. One has just over 100 hours and the other has about 4300 hours. The low-hours unit doesn’t have the deep blacks that the other unit has. I’ve played with the sub-brightness level in the service menu, but the black level bottoms out at a darkish grey no matter what you do.

Could this simply be a matter of the TV being new and needing to ‘settle in’, where the blacks will deepen with use? Or alternatively is there a hardware fix that can help? It seems a bit odd as they’re the exact same model..

[Syntax]

Try SBR, SCL, SCON or SPIX.

Just need to drop it 1 or 2 levels.

[Taiyaki]

Different Sony tubes come with different default settings for brightness and contrast and usually has more to do with the model itself than the specific unit (meaning all units of that model made at that time with likely come with similar levels). Some new tv's come out of box with either grey blacks or more frequently the reverse, black crush, and usually need some adjustment. You're correct in adjusting the brightness as that's the setting you need to work with. You can adjust the sub brightness if needed as well.

[andykara2003]

Thanks both and sorry for the delay - I hadn’t had a chance to check out the service menu until now.

Syntax - isn’t SCL and SCON just sub-colour and sub-contrast? If so, i can’t understand why they’d affect base black levels, although I accept I’m probably not seeing something as you’re much more experienced than I am. Also, what’s SPIX?

[Taiyaki]

I don't know of SCL but sub color is more frequently "SCOL". As far as I know SPIX is sub contrast, I think some models had SPIX, but most use SCON. Usually contrast on Sony crt's adjust the picture setting aka the luminosity, in your case reducing it might help change the grays to black, but it goes without saying doing so will also dim the overall image, you might benefit by doing a combination, but it's really the brightness setting you want to adjust for this.

[andykara2003]

, but it's really the brightness setting you want to adjust for this.

That’s what I thought - but even if you go really low with brightness, a floor is reached and the greys stop deepening.

[Taiyaki]

, but it's really the brightness setting you want to adjust for this.

That’s what I thought - but even if you go really low with brightness, a floor is reached and the greys stop deepening.

If it requires a ton of adjustment, as in going to the extremes of sub brightness + regular brightness adjustment, and on top of that you're not even seeing blacker blacks, then that's definitely not right, there might be something else going on. Sorry I can't be of more help, maybe someone else with the same or similar model as yours might be able to give some insight.

[Syntax]

Could have had the flyback turned up too high from stock. Try turning SCREEN on the flyback down a hair if none of the settings i mentioned previously had any effect.

[andykara2003]

I was wondering about that - thanks Syntax.

[Taiyaki]

Oh gosh, yeah SCREEN, might be G2 on some model Sony's. I hate touching that knob as the only time I adjusted it I created retrace lines all across the screen so I had little flexibility with how much I could touch it. On your set this could be worth trying though.

[andykara2003]

Thanks, I think you’re right. I vaguely remember someone saying to be careful with it - basically I think the adjustment pot tends to be pretty sensitive, so I’ll need to turn it in very small increments..