I’ve been struggling with getting my black level detail correct. The black bars pattern from AVIA is showing me a completely black screen – even on the tube face I couldn’t see the moving black bars.
I was certain that I had in the past had done the brightness and contrast setup, but since then I’ve changed cables, DVD player, and other factors. So I’ve spent some time going back to verify that cables didn’t make a difference, and checked the setup on my DVD player. Nothing seemed to make a difference.
I looked for help on Curt Palme’s CRT forums with this posting. The users there are very helpful, and TSE (scott – an Ampro expert) pitched in with exactly the advice I needed.
The sub-brite controls can put the darker video levels out of range of the video amplifiers. If too low the dark information is gone. Turn contrast to a low level like 20 or 30. Set brite to 70. Turn up G-2 so tube screen is totally lit up. Adjust sub-brite so lowest video levels are visible. Look in lens to see. Then set G-2 properly. The SB50 pics have sub-brite set so darkest video information is just visible. SB11 pics have sub-brite set toward low end of range. With sub-brite too low the lower levels of the stairstep pattern are not there. The tube is lit up but there is no information. Don’t turn the sub brites too high as it makes the amplifiers run hotter than they need to. Just enough for the dark information to show.
Scott
He even provided screen shots and scope shots! I’m sure I can fix this black level problem now. More when I get a chance to poke at the projector.