CurtPalme.com Home Theater Forum

[joatmon]

I need help from you experts.

In very dark scenes I can see a band on the upper part of my screen that I can't get rid of. Here is a photo of what it looks like on the green tube (it's visible on all 3):



I'm not sure what you call this. Banding?

Projector is a Runco DTV-940 with a build date of Jan/2001.

This is what I know so far:
- the dark band is only visible on dark images
- happens with RGB and component inputs (I've tried different sources too)
- observed on 480p/720p/1080i modes
- the dark band stays in the same spot of the image (I can move the raster around and it moves with the image)
- the dark band moves with the top blanking control (I cannot blank it out)


Something that I wonder about is a short instability of the vertical deflection after a retrace. I don't know if this is normal as I don't know what normal is supposed to look like (this is my 1st PJ and only one I've seen working). This image is from the green raster centering option in initial setup menu (same image seen on all 3 tubes).

The reason I bring this up is that I'm wondering if it might be related to the above issue.


Thanks in advance for any help ya'll can provide.

[JustGreg]

Congrats on your first CRT pj!

I know nothing about Runco's but I thought I'd bump this to the top for you because frankly I'm curious if the banding problem of a Runco is caused by the same settings as a Marquee 8500. I've done it to mine more times than I can count because I 'just had to tweek it a litttttttle bit more'.

You 'may' end up doing a full reset of the pj and starting over. If this is your first CRT pj then starting over isn't a bad thing because each and every time you do it you learn a little more. Each setup after that gets a bit easier each time. It's possible that you fully understand what all the adjustments do but because you're new to CRT setup you 'might' have gotten a little greedy while adjusting things. For the most part all CRT pj's have iterative adjustments; eg, one setting affects another and there's alot of back and forth to get it just right.

For me personally, once I get past the magnetics alignment (Marquee 8500) it's actually enjoyable... but I wear glasses so I spend alot of time second guessing what I'm seeing as I do astig and focus. (Lots of eye blinking too ) I have a pretty ugly lower back problem so stooping under the thing is the pits! (I'm 6'4" and the ceiling mounted pj...isn't).

Good luck!

[dvh99]

now we at least know why your back aches.
but looking at his picture i think its something more than the banding with a marquee (not all models btw).

[JustGreg]

[joatmon]

UPDATE:

I've discovered that adjustment of the G2 controls moves the location of where the dark band stops and 'normal' starts, but naturally this causes the corresponding ABL led to turn on. So I'm now at the point where the location of the dark band can now be moved around on each tube.

To summarize, the upper blanking control moves the band on all three tubes and the G2 adjustment changes the height of the band on each individual tube.

Anyone know if it's possible to disable ABL on the 708/Cine7?

[jarseneau]

Just taking a guess but have you tried changing the SHIFT adjustment for this problem. In my case, I can get odd retrace lines (like the ones showing on the bottom edge of your picture) only mine show at the bottom of the projected image. I can get those if I try to shift the image down such that the shift value goes negative. If I go much below 0, I'll start to see the retrace lines.

I wonder if you might have your SHIFT set to a high value and that is leading to the banding. If that worked you could re-center your image by using the raster centering controls or maybe tilting the pj slightly.

[CIR Engineering]